Food Safety Applications using Atomic Absorption Spectrometry

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Thermo Scientific iCE 3000 SeriesAtomic Absorption SpectrometersRefreshingly Different

Food Safety Applicationsusing Atomic AbsorptionSpectrometry

Over the past few years, food safety has become an increasinglyimportant topic in the world of consumer safety. As scientificunderstanding and consumer awareness increases, more and morestringent legislation is placed on foodstuffs, particularly relating totrace elemental analysis of toxic metals. Food manufacturers must testraw materials, intermediates, and final saleable products. While someelements offer nutritional benefit, others, such as arsenic, cadmium,lead and mercury are toxic and must be strictly monitored. Flame,furnace and vapor atomic absorption techniques offer a flexible solutionto the analysis of trace elements in foodstuffs.

This information pack has been compiled to present a range of foodsafety applications, demonstrating how flame, furnace and vaportechniques can be used for the analysis of major, minor and toxicelements in food. The pack also includes information on a range ofproducts and accessories to facilitate fast, accurate and reliableanalysis.

Welcome to the food safety pack forAtomic Absorption analysis

Product Information • Product Specification for the iCE 3500 Atomic Absorption Spectrometer• Product Specification for Thermo Scientific Graphite Furnace Television• Product Specification for VP100 Continuous Flow Vapor Generation System

Food Safety Applications• The Analysis of Trace Elements in Honey by Flame and Graphite Furnace

Atomic Absorption Spectrometry• Accurate Analysis of Low Levels of Mercury in Fish by Vapor Generation AA• Determination of Trace Elements in Rice Product by Flame and Graphite Furnace

Atomic Absorption Spectrometry• The Analysis of Cadmium in Chocolate by Graphite Furnace

Atomic Absorption Spectrometry

Article• Atomic Absorption: Feeding the Food Safety Market

Table of Contents

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The Analysis of Trace Elements in Honey byFlame and Graphite Furnace Atomic AbsorptionSpectrometryDr Hazel R. Dickson, Applications Chemist, Thermo Fisher Scientific, Cambridge, UK.

Key Benefits• The robust flame sample introduction system allowsdissolved honey samples to be run without blockage orcontamination.

• The advanced furnace autosampler speeds up analysisby automatically preparing the working standards froma single master standard.

• The permanently aligned true dual atomizer enablesrapid switching between flame and furnace methods.

• Deuterium and Zeeman background correction offer aflexible solution for the analysis of challenging matricessuch as honey.

Summary The Thermo Scientific iCE 3500 Atomic AbsorptionSpectrometer is the ideal solution for the analysis ofmajor, minor and toxic elements in honey. Thepermanently aligned true dual atomizer allows robust andreliable analysis of major elements by flame, followed byaccurate and precise determination of minor and toxicelements by graphite furnace.

IntroductionHoney is a sweet and viscous substance produced from thenectar and secretions of plants and flowers. The nectar istransported to a beehive by honey bees, where worker beesthen add enzymes to create honey. Most honey is createdfrom a variety of plants and flowers, though in some areas,where a particular plant or flower is in abundance,monofloral honey can be produced, and this is particularlyvaluable. Honey is typically advertised to the consumer byfloral source or geographical location, however many honeyproducts are blended from a variety of sources. This hasresulted in a global market with hundreds of types of honey,each with unique taste, color and crystallization properties.In the EU, honey must adhere to strict composition criteria,including sugar, moisture and hydroxymethylfurfural (HMF)content.1

Sugar is often substituted with honey in the making ofcake products. Not only is honey sweeter than sugar, andtherefore used as a sugar alternative, it is also hygroscopic.This causes it to attract and hold water, resulting indeliciously moist baking products. Honey is predominantlyfructose and glucose, combined with a mixture of othernatural ingredients such as organic acids and enzymes. Italso contains a small percentage of metals, includingpotassium, sodium, magnesium and calcium. The metalcomposition is geographically significant, as the majority ofmetals in honey are transferred from the soil to the plant orflower from which the nectar is collected. Metals can also betransferred from other sources such as water aerosol sprayand atmospheric pollution. The metal profile of honey istherefore significantly important on three levels – forevidence of provenance, nutritional benefit and toxicologicalimplications.

The viscous and sugary nature of honey makes it adifficult substance for quantitative trace elemental analysis.Honey can be dissolved in water; however this can result incontamination of sample introduction systems, such asgraphite furnace cuvettes. In addition, standards mayrequire matrix matching to take into account the change inviscosity and the increased organic content. As a simpleralternative, acid digestion can be used to remove the organicmaterial from the sample prior to dilution with water.

This application note presents two methods for theanalysis of trace elements in honey. A simple dissolutiontechnique is used for the analysis of two typical majorelements by flame atomic absorption spectrometry, while amicrowave-assisted digestion protocol is implemented forthe analysis of two toxic contaminants by graphite furnaceatomic absorption spectrometry.

Key Words

• Atomic Absorption

• Flame

• Deuterium

• Graphite Furnace

• Honey

• Zeeman

ApplicationNote: 43060

Sample Preparation

Reagents• Nitric acid, 69 %, trace metal grade

• Hydrogen peroxide, > 30 % w/v, trace metal grade

• 1000 ppm cadmium, lead, magnesium and sodium masterstandards

• Magnesium nitrate

All standards and reagents purchased from Fisher Scientific.

Preparation by dissolution for flame analysisThree honey samples (Spanish Orange Blossom, AustralianEucalyptus and Brazilian Pure Set Honey) were purchasedfrom a local supplier. The honey samples were warmed withrotation in a water bath (in their original containers) atapproximately 60 °C in order to homogenize each sample.Aliquots of approximately 10 g of honey were transferred toclean glass beakers and weighed. Approximately 1 g ofhoney was transferred from the beaker to a volumetric flaskand the mass determined by difference. The sample wasdiluted to approximately 100 g with 1 % nitric acid and the% m/m concentration and dilution factor determined. It wasnecessary to sonicate the honey/water sample to ensurecomplete dissolution.

Preparation by microwave-assisted digestion forfurnace analysisHoney samples were warmed with rotation in a water bath(in their original containers) at approximately 60 °C inorder to homogenize each sample. Aliquots ofapproximately 10 g of honey were transferred to clean glassbeakers. Approximately 0.25 g portions of honey wereweighed into clean, dry Teflon microwave digestion vessels.(NB: the hygroscopic nature of honey and the insulatingproperties of Teflon make it a difficult substance to weigh,as the honey is attracted to the Teflon surface. A pipette wasused to deposit honey directly onto the base of the digestionvessel. It was also necessary to use an anti-static gun todischarge the digestion vessels prior to weighing). 4 ml nitricacid and 2 ml hydrogen peroxide were added to the honeysamples which were left uncovered for 15 mins. The sampleswere sealed and digested via temperature ramping (rampedto 120 °C for 10 minutes, held for 5 minutes, then rampedto 200 °C over 10 minutes, then held for 15 minutes). Asample blank containing only nitric acid and hydrogenperoxide was prepared in the same way. The digestedsamples were quantitatively transferred to 100 mlvolumetric flasks.

Standard and Reagent PreparationFlame calibration standards were prepared on a v/v basis in1 % nitric acid. 1000 ppm standard stock solutions ofmagnesium and sodium were used to prepare 1.0, 2.0 and10 ppm multi-element standards by pipetting 0.1, 0.2 and1.0 ml of stock solutions into 100 ml volumetric flasks andmaking to the mark with 1 % nitric acid. The 10 ppmmulti-element standard was used to prepare 0.3 and 0.5ppm multi-element standards by pipetting 3.0 and 5.0 ml ofthe 10 ppm sub-standard into 100 ml volumetric flasks andmaking to the mark with deionsed water. A blank of 1 %nitric acid was also prepared. Standards of 0, 0.3, 0.5, 1.0and 2.0 ppm were used to generate calibration curves formagnesium and sodium. (NB: corresponding calculateddilution factors were used to quantify the prepared samplesusing the v/v flame calibration standards).

Furnace calibration standards were prepared on a v/vbasis in 4 % nitric acid, to ensure acid matrix matching tothe samples. 1000 ppm standard stock solutions ofcadmium and lead were used to prepare a 1 ppm multi-element sub-standard by pipetting 0.1 ml aliquots into a100 ml volumetric flask and diluting to the mark with 4%nitric acid. The sub-standard was subsequently used toprepare a method master standard of 20 ppb by pipetting2 ml into a 100 ml volumetric flask and making to the markwith 4 % nitric acid. The furnace autosampler was used toautomatically prepare calibration standards at 2, 5, 10,15 and 20 ppb. A calibration blank of 4 % nitric acid wasalso prepared.

Magnesium nitrate was prepared as a matrix modifierfor use with lead analysis by dissolving 1 g in 100 mldeionised water, such that a 5 μl aliquot added 50 μgmagnesium nitrate to the sample.

Method Development and Analysis

Flame MethodMagnesium and sodium were analyzed by flame atomicabsorption spectrometry. The lateral and rotational burnerpositions and the impact bead were optimised manuallyusing the 1 ppm multi-element standard. Burner height andgas fuel flow were optimized individually and automaticallyfor each element as part of the analytical method.Spectrometer parameters are shown in Table 1.

Spectrometer Parameter Magnesium Sodium

Flame type Air/Acetylene

Fuel flow, l/min 1.0

Burner height / mm 8.6 6.2

Wavelength / nm 285.2 589.0

Bandpass / nm 0.2

Background correction Deuterium None

Measurement time / s 4

Number of resamples 3

Calibration type Segmented curve fit

Table 1: Spectrometer parameters for the analysis of magnesium and sodium inhoney by flame atomic absorption spectrometry.

Furnace MethodCadmium and lead were analyzed by graphite furnaceatomic absorption spectrometry. Default spectrometerparameters were found to be suitable for each element andlead required the addition of 50 μg magnesium nitratematrix modifier for optimum peak shape and recovery asrecommended in the Solaar software cookbook.Spectrometer parameters are shown in Table 2.

Spectrometer Parameter Cadmium Lead

Wavelength / nm 228.8 217.0

Cuvette Electrographite ELC(Extended Life

Cuvette)

Dry temperature / °C 100

Ash temperature / °C 800

Atomize temperature / °C 1000 1200

Bandpass / nm 0.5

Background correction Zeeman

Signal measurement Transient Height

Number of resamples 3

Calibration type Quadratic least squares fit

Table 2: Spectrometer parameters for the analysis of cadmium and lead inhoney by graphite furnace atomic absorption spectrometry.

Results and Discussion

Analysis by FlameHoney samples were diluted in 1 % nitric acid asdescribed above and analyzed by flame atomic absorptionspectrometry following automated optimization of theburner height and gas fuel flow. Analysis was found to bestraightforward. Calibration curves for magnesium andsodium are shown in Figure 1.

Figure 1: Calibration curves for the analysis of magnesium and sodium inhoney samples by flame atomic absorption spectrometry.

To verify the method, an additional honey samplewas prepared with a spike equal to 0.2 ppm in the dilutedsample and the percentage recovery calculated. Results areshown in Table 3.

Sample Concentration in originalhoney sample / ppm

magnesium sodium

Spanish Orange Blossom 9.26 16.9

Australian Eucalyptus 25.33 94.08

Brazilian Pure Set 25.14 42.83

Spiked Honey

Measured concentration 0.196 0.187in solution / ppm

% Recovery 96 92

Table 3: Results following the analysis of honey samples by flame atomicabsorption spectrometry for magnesium and sodium.

This testing revealed the presence of magnesium andsodium in each of the analyzed honey samples. Accordingto the literature, these elements are expected in honey,however the levels vary greatly, depending upon thecountry of origin, local environment and flower type.2

Excellent recoveries on the spiked samples were obtained,demonstrating the suitability of this method for theanalysis of majors in honey by flame atomic absorptionspectrometry. Analysis took only 12 seconds for atriplicate reading on a single sample.

Analysis by FurnaceHoney samples were digested in a high pressuremicrowave digestion system and analyzed by graphitefurnace atomic absorption spectrometry. The furnaceautosampler was used to automatically prepare standardsfrom a single master standard and the matrix modifierwas automatically injected into the cuvette for the analysisof lead. Cadmium and lead were not detected in analyzedhoney samples. To verify the method, an additional honeysample was prepared with a spike equal to 5 ppb in thediluted sample. The spike was added prior to microwavedigestion and the spiked sample was subsequently digestedin the same way as described above. The percentagerecovery was calculated and results are shown in Table 4.

Cadmium Lead

Measured Concentration 4.66 5.49in solution / ppb

% Recovery 93 110

Table 4: Spiked recoveries following the analysis of honey samples bygraphite furnace atomic absorption spectrometry for cadmium and lead.

ConclusionThis application note has demonstrated how trace elementsin honey can be quantitatively determined using atomicabsorption spectrometry. A simple dissolution method wasused to prepare samples for the analysis of magnesium andsodium by flame, while a microwave-assisted digestionprocedure was used for the accurate and precise analysis ofcadmium and lead by furnace. Spiked samples were usedto verify each method and recoveries were found to be verygood. The iCE 3500 Atomic Absorption Spectrometerproved to be a robust and reliable solution for the analysisof trace elements in honey.

References

1. Official Journal of the European Communities,Council Directive 2001/110/EC of December 2001relating to honey.

2. P. Pohl, Trends in Analytical Chemistry, Vol. 28, No. 1, 2009


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Accurate Analysis of Low Levels of Mercury inFish by Vapor Generation AADr Hazel R. Dickson, Applications Specialist and Rebecca Price, AA Product Manager, Thermo Fisher Scientific, Cambridge, UK

Key Benefits• The dedicated vapor generation accessory (VP100)

offers fast, repeatable and robust analysis

• The sensitivity and precision of the method easily meetsthe detection limits required by all current internationalguidelines

• The SOLAAR software is easy to use and gives step-by-step instructions to allow quick set-up and optimizationof the method

SummaryThe Thermo Scientific iCE 3000 Series Atomic AbsorptionSpectrometers are the perfect tool for the measurement oflow levels of mercury in fish. With the addition of aVP100 vapor generation accessory the iCE 3000 SeriesAtomic Absorption Spectrometers are capable of reachingdetection limits of 0.07 ppb (μg/L) in solution. This isequivalent to 0.014 mg/kg in the initial fish sample (basedon a 0.5 g in 100 mL preparation), which easily meets thestandards demanded by food safety legislation throughoutthe world. This method is also very fast and allowsanalysis in around 90 seconds per sample.

IntroductionMercury is a significant and toxic environmental pollutantthat can be deadly to humans. It is found in three differentforms: the metallic element, inorganic salts and organiccompounds (e.g., methyl mercury, ethyl mercury and phenylmercury). Elemental mercury can be released into theatmosphere by natural occurrences such as volcanic eruptions,but the majority is produced by human activities. Coal-fired power plants, waste incineration, metal processingand cement production produce approximately 75 % ofthe 5,500 tons of mercury that are released into theatmosphere each year1.

Due to mercury’s low boiling point it becomes airbornevery easily. Once in the atmosphere it can travel hugedistances before eventually being deposited in rivers oroceans. In aquatic environments mercury is transformedinto methyl mercury by both microorganisms and abioticreactions. The methyl mercury becomes increasinglyconcentrated in the marine food chain, in a processreferred to as biomagnification, and can reach extremelyhigh levels in predatory fish such as swordfish, tuna, kingmackerel and shark. The consumption of these fish andother marine organisms is the main route of humanexposure to methyl mercury.

The toxicity of methyl mercury was first recognized inJapan after a chemical company released large amounts ofmethyl mercury into Minamata Bay. This caused severemercury poisoning in local people, with symptoms includingdamage to hearing and speech, muscle weakness and visualimpairment. In severe cases paralysis, coma and deathfollowed within weeks of the onset of symptoms. Thereason for the acute toxicity of methyl mercury to humansis because of its ability to pass through the meninges intothe brain. Similarly, in pregnant women, methyl mercurycan cross the placenta and damage the developing nervoussystem of the fetus.

The recognition of the toxicity of methyl mercury andthe realization that fish is the major source for humanshas led to the development of legislation by governmentsand health organizations throughout the world. The majorityof countries and global organizations now enforce maximumconcentrations of mercury in fish of approximately 0.5 mg/kgwet weight. There are differences in maximum mercurylevels between countries and some variations dependingon the type of fish. Most countries also legislate specificallyfor methyl mercury, although there are some that provideguidelines for total mercury levels too. For more detailedinformation see Table 1.

Key Words

• AtomicAbsorption

• Fish

• HydrideGeneration

• Mercury

• Methyl Mercury

• MicrowaveDigestion

• Vapor Generation


Table 1: The maximum or guideline levels for mercury in seafood adopted byvarious countries or international regulatory bodies

The iCE 3000 Series Atomic AbsorptionSpectrometers and accessories are perfect tools for theanalysis of low levels of mercury in fish. For laboratoriesinterested in total mercury measurements they providefast and accurate analysis of samples with detection limitsbelow 0.07 ppb (μg/L) in solution. This equates to0.014 mg/kg in the original fish sample, based on a0.5g in 100 mL preparative method. For laboratoriesanalyzing methyl mercury, the iCE 3000 Series AtomicAbsorption Spectrometers provide an excellent screeningtool. Their cost-effectiveness and ease-of-use makes thema perfect partner to more complex and expensivetechniques, such as HPLC-ICP-MS or GC-ICP-MS.

This application note gives details of the reagents,sample preparation and instrument conditions needed toanalyze low levels of mercury in fish. The method hasbeen evaluated using both spiked fish samples andcertified standard materials containing mercury levelsrelevant to current global legislation.

InstrumentationThe Thermo Scientific iCE 3500 Atomic AbsorptionSpectrometer was used during this analysis, althoughsimilar results could also be obtained on both the iCE3300 and the 3400 models. The iCE 3000 Series AtomicAbsorption Spectrometers combine high-precision optics,state-of-the-art design and user-friendly software toprovide unrivalled analytical performance.

A VP100 vapor generation accessory is also necessaryto perform this analysis. The unique VP100 uses a continuousflow system to produce a steady-state signal and providesexcellent analytical precision. The continuous flow ofreagents ensures that the system is self-cleaning, reducingmemory effects and increasing sample throughput. TheVP100 is entirely controlled by the SOLAAR software,meaning that setting up a method and running an analysisis extremely simple.

A mercury cell (provided as standard with the VP100)was also used. This accessory provides an increased path-length compared to a normal vapor cell and givesexceptionally low detection limits.

Sample and reagent summaryThe sample preparation procedure is shown in Figure 1.There are four main sections: sample drying, samplepreparation, sample digestion and mercury reduction. Thedrying section may not be applicable for all situations, asit is only necessary if the final mercury concentration isneeded as a dry weight value, e.g., mg/kg dry weight.Most countries and official regulatory bodies (e.g., CodexAlimentarius, US FDA, EU Commission) specifyconcentrations of mercury in a wet weight of sample.

Mercury Level

Organisation Limit Type Fish Type Total Organic(mg/kg) (mg/kg)

EU Commission Maximum Level1 Non-carnivorous fish & crustaceans8 0.5

Carnivorous fish8 1

Codex Guideline Level2 Non-carnivorous fish & crustaceans8 0.5

Alimentarius Carnivorous fish8 1

US FDA Maximum Level3 Fish, shellfish, crustaceans & 1other aquatic animals

China Maximum Level4 Fish (excluding carnivorous fish) 0.5& other aquatic products

Carnivorous fish (e.g., shark, tuna, etc.) 1

Japan Maximum Level5 All fish, shellfish & aquatic products 0.4 0.3

Australia Maximum Level6 Crustaceans, molluscs & 0.5non-carnivorous fish

Carnivorous fish & fish samples with 1low sample numbers

Canada Maxiumum Level7 Edible portion of all retail fish 0.5with six exceptions8

Edible portion of six carnivorous fish8 1

1 Commission Regulation (EC) No 1881/2006 of 19December 2006: Setting maximum levels for certaincontaminants in foodstuffs

2 Codex General Standard for Contaminants and Toxinsin Foods CODEX STAN 193-1995,Rev.3-2007

3 Action Levels for Poisonous or DeleteriousSubstances in Human Food and AnimalFeed (2000)

4 USDA Foreign Agricultural Service, GAIN Report(CH6064), "China, Peoples Republic of; FAIRS ProductSpecific; Maximum Levels of Contaminants in Foods;2006)

5 National Oceanic and Atmospheric AdministrationTechnical Memorandum, "A survey on Japan's importregulations on fish and shellfish products" (1980)

6 Standard 1.4.1 – Contaminants and Natural Toxicants

7 Canadian Standards ("Maximum Limits") for VariousChemical Contaminants in Foods

8 See the specific standard for details of the exact fishspecies that fall under each limit

Homogenize fish sample ina food processor

Homogenize fish sample ina food processor

Place in an ovenat 80˚C

Place in an ovenat 80˚C

Leave until sample is ata constant weight

Leave until sample is ata constant weight

Weigh out approximately0.5 g of homogenized fish

Weigh out approximately0.5 g of homogenized fish

Add 1ml of 1000 ppb Hgstandard (final spike of 10ppb)

Place into digestion vessel Place into digestion vessel

Add 10 ml HNO3 Add 10 ml HNO3

Leave vessels open in a fumehood for at least 30 min

Leave vessels open in a fumehood for at least 30 min

Seal vessels and digest2 Seal vessels and digest2

Allow vessels to cool Allow vessels to cool

Transfer digested sample intoa 100 ml volumetric flask

Transfer digested sample intoa 100 ml volumetric flask

Add 60 ml potassiumpermanganate solution (6%)


Leave sample vessel looselycapped for at least 2hrs


Slowly add 15 mlhydroxylamine chloridesolution (20%m/v)3


Add deionised H2O to bringsample volume to 100 ml






Add volumes of 1000 ppb Hgsolution (see table 4)

Add 10 ml HNO3 to a100 ml volumetric flask

MERCURY REDUCTION

SAMPLE DIGESTION

SAMPLE PREPARATION

SAMPLE DRYING1

Produce sample Produce sample spike Calibration standard in matrix

1 Sample drying phase is not necessary if the final concentration of mercury is neededfor a wet-weight sample

2 Refer to the manufacturers guidelines when designing a digestion program.An example of a program is given in Table 3

3 CARE: The reaction is exothermic and the flask may become hot. Also, make sureto add the hydroxylamine chloride slowly, otherwise the solution may foam andeject some sample from the flask.

Figure 1: The procedure for preparing samples, sample spikes and matrix-matched standards for the analysis of mercury in fish

Three different types of fish sample were used duringthe evaluation of this method: fresh fish (salmon) obtainedfrom a local supermarket; canned fish (sardine), also obtainedfrom a local supermarket; and DORM-2 certified referencematerial (National Research Council of Canada, Institutefor National Measurement Standards, Ottawa, Canada).

Table 2 summarizes all the reagents necessary for theanalysis.

Consumables

Nitric Acid

Potassium Permanganate

Hydroxylamine Chloride

Mercury Standard Solution (1000 ppm in 10 % HNO3)

Stannous (Tin (II)) Chloride

Hydrochloric Acid

Table 2: Summary of all the reagents used during this analysis

If dry weight measurements are needed then the fishsamples should be homogenized and dried in an oven at80°C until they reach a constant weight. Alternatively, thefish tissue can be freeze-dried and homogenized using amortar and pestle. After drying, portions of approximately0.5 g should be accurately weighed out for digestion. Forwet weight measurements the fresh fish should behomogenized in a food processor and a portion ofapproximately 0.5 g should be accurately weighed andplaced in a microwave digestion vessel. This provides arepresentative fish sample.

Following preparation in this manner, 1 mL of 1000ppb Hg standard solution was added to half of the salmonand sardine samples. This spike gave a concentration of10 ppb Hg in the final 100 mL sample. The other half ofthe samples did not have mercury added to them to allowthe calculation of spike recoveries.

The microwave digestion vessels containing the sampleswere placed in a fume extraction hood before adding 10 mLconcentrated HNO3. The vessels were left for at least 30 minuteswithout their lids on to allow gases to escape. After thistime the vessels were placed into a microwave digestionsystem and digested using the program shown in Table 3.It is also possible to use a hot-block digestion to obtainsuitable results.

Power Ramp Max. Pressure Max Temperature HoldMax (W) % (min) (psi) (˚C) (min)

800 100 30 180 190 15

Table 3: Microwave digestion program used

After digestion the samples were transferred to a 100 mLgraduated flask and 60 mL of 6% potassium permanganatesolution was added. The sample vessels were left for atleast 2 hours to ensure that all the mercury in the samplewas reduced to Hg2+.

It is very important to check that the vessels are notsealed during this stage, as gases are produced that couldcause pressure to build up.

After the mercury was reduced, 15 mL of 20%hydroxylamine chloride solution was added to remove the

excess potassium permanganate. Care was taken duringthe addition of the hydroxylamine chloride, as thisproduces an exothermic reaction and the vessel maybecome hot.

It is essential to add the hydroxylamine chlorideslowly during this stage and to gently mix the solutionduring the addition. Without these precautions a violentreaction may occur that could eject some sample from theflask, leading to inaccurate results.

After allowing the solution to cool, deionised waterwas added to make the volume up to 100 mL.

Standard preparationStandards were prepared from a 1000 ppm (mg/L) mercurystandard solution. This standard was first diluted to producea 1000 ppb (μg/L) stock solution to allow simple preparationof a range of standards. To demonstrate the linear rangeof the iCE 3000 Series Atomic Absorption Spectrometers awide range of standards were used (1 – 100 ppb). Thestandards were matrix matched and prepared in the sameorder as the samples. The procedure is summarized inFigure 1 and the exact volumes needed to prepare thestandards are shown in Table 4.

VP100 reagent preparationThe VP100 requires both a reductant and an acid solutionto perform the reactions that form the gaseous mercury.For this application the reductant was a solution of 7.5 %stannous chloride (SnCl2) stabilized in 10 % HCl. Theacid solution was 50 % HCl. Refer to Table 5 for someguideline figures of how much reductant and acid mightbe needed.

1 Reagent use based on a total sample analysis time of 90 seconds. This isequivalent to the signal stabilization time and five resamples, each taking fourseconds

2 This approximation is based on the time taken for the system to stabilize duringthe analysis of a 10 ppb standard solution

Table 5: Estimate of reagent use during the analysis described in thisapplication note

Standard

Blank 1 2 3 4 5 6 7

Final Concentration Hg ppb 0 1 2 5 10 20 50 100

Volume 1000 ppb Hg mL 0 0.1 0.2 0.5 1 2 5 10Stock Solution

Volume Conc. HNO3 mL 10 10 10 10 10 10 10 10

Volume Potassium mL 60 60 60 60 60 60 60 60Permanganate Solution (6%)

Volume Hydroxylamine mL 15 15 15 15 15 15 15 15Chloride (20%)

Volume Deionized H2O mL 15 14.9 14.8 14.5 14 13 10 5

Total Volume mL 100 100 100 100 100 100 100 100

Table 4: Volumes of stock standard and other reagents needed to prepare arange of standard solutions

Pump GasSpeed Flow

(rpm) (mL/min)

40 200

SignalReagents used per sample1 Stabilization2

Acid Reductant Sample(mL) (mL) (mL) (s)

1.40 3.20 15.00 70

Instrument ConditionsThe analysis was performed using the most sensitiveabsorption wavelength for mercury at 253.7 nm. Fiveresamples were used, with each resample taking four seconds.This was used to thoroughly assess the short-term stabilityof the instrument during the development of this method.For normal use, three resamples would be adequate.Deuterium background correction was used throughoutthe analysis. The parameters used for both the VP100 andspectrometer are shown in Table 6. For further details onhow to optimize the VP100 parameters for your analysis,please refer to the iCE 3000 Series Operator Manual.

Table 6: Summary of the parameters used for the analysis of mercury in fishfor this application note.

ResultsThe calibration curve showed excellent linearity up to 100 ppb(Figure 2), which is equivalent to 20 mg/kg in a fish sample(assuming a sample weight of 0.5 g) with an R2 value of0.9989. This shows the superb performance of the iCE3000 Series Atomic Absorption Spectrometers over a wideconcentration range. This calibration is equivalent toconcentrations of 0 – 20 mg/kg mercury in the originalfish samples, assuming a sample mass of exactly 0.5 g.The % relative standard deviations (%RSDs) for each ofthe standards were less than 2.5 %. This demonstratesthe excellent stability of both the spectrometer and theVP100 accessory.

Figure 2: Calibration curve produced for the analysis of mercury in fishsamples. Matrix matched standards were used.

The method detection limit (MDL) and characteristicconcentration were calculated using the automated‘Instrument Performance’ Wizard in the SOLAAR software.This user-friendly feature guides you through the stepsnecessary to quantify the performance of your method. Italso automates all of the data processing, making theentire procedure quick and easy.

The method was found to have a detection limit of0.068 ppb (μg/L) in solution. This equates to a MDL of0.014 mg/kg in the original fish sample (assuming a samplemass of 0.5 g). The MDL provides a measure of the noiseand stability of the system. A lower detection limit allowsyou to confidently determine lower concentrations of mercuryin your samples.

The characteristic concentration is related to thesensitivity of the method. The characteristic concentrationof this method was found to be 0.724 ppb in solution. Thiswould be the equivalent of 0.145 mg/kg in the initial fishsample (assuming a sample weight of 0.5 g).

1 The detection limit and characteristic concentration of the sample is based on asample mass of 0.5 g

Table 7: Detection limit and characteristic concentration data

Salmon and sardine samples were spiked with 10 ppbmercury prior to digestion and compared with unspikedsamples to calculate recoveries. These 10 ppb spikeswould correspond to a concentration of 2 mg/kg innormal fish samples (assuming a sample weight of 0.5 g)and demonstrate the accuracy of the analysis at levelsappropriate to current legislation. The spike recoveries areshown in Tables 8 and 9. The agreement with expectedresults is excellent, with the recovered values all fallingwithin 6 % of the expected values. This demonstratesthe repeatability and accuracy of both the sampledigestion procedure and the vapor analysis using theThermo Scientific iCE 3000 Series Atomic AbsorptionSpectrometers.

Sample Expected Meaasured PercentageConcentration Concentration Recovery

(mg/kg) (mg/kg) (%)

Sardine 1 2 1.93 97

Sardine 2 2 2.08 104

Sardine 3 2 1.91 95

Table 8: Table of results showing the expected concentration, measuredconcentration and percentage spike recovery for three separate sardinesamples


(mg/kg) (mg/kg) (%)

Salmon 1 2 1.89 94

Salmon 2 2 1.94 97

Salmon 3 2 1.99 99

Table 9: Table of results showing the expected concentration, measuredconcentration and percentage spike recovery for three separate salmonsamples

Spectrometer Parameters

Wavelength 253.7 nm

Lamp Current 75 %

Bandpass 0.5 nm

Background D2 QuadlineCorrection

Resamples 5

Measurement 4.0sTime

VP100 Parameters

Pump Speed 40 rpm

Gas Flow 200 ml/min

Acid Reagent 50 % HCI

Reductant 7.5 % stannous chloridein 10 % HCI

Measurement Delay 70

Pump GasSpeed Flow

(rpm) (ml/min)

40 200

Detection CharacteristicLimit Concentration

Solution Sample Solution Sample(ppb) (mg/kg)1 (ppb) (mg/kg)1

0.07 0.01 0.7 0.1

To ensure the accuracy of the sample preparation,digestion and analysis, three separate samples of theDORM-2 standard reference material were also analyzed(Table 10). The recoveries from these samples were alsoexcellent, with an accuracy of ±2% or better.


(mg/kg) (mg/kg) (%)

DORM-2 1 4.64 ± 0.26 4.59 99

DORM-2 2 4.64 ± 0.26 4.53 98

DORM-2 3 4.64 ± 0.26 4.57 98

Table 10: Table of results showing the expected concentration, measuredconcentration and percentage spike recovery for three samples of theDORM-2 reference material

ConclusionsThe results shown in this application note show that theiCE 3000 Series Atomic Absorption Spectrometers andVP100 vapor generation accessory offer excellent linearrange, stability and accuracy during the analysis of tracelevels of mercury in fish. Their superb sensitivity andexcellent detection limits easily meet the levels required forall current worldwide legislation (Table 1). The speed andefficiency of the VP100 allows the analysis of a sampleapproximately every 90 seconds. The SOLAAR softwarecontrols every aspect of the spectrometer and VP100 andmakes setting up the method quick and simple. Thesecharacteristics mean that the iCE 3000 Series AtomicAbsorption Spectrometers provide an ideal solution forthe screening and analysis of fish samples for potentialmercury contamination.

References1 United Nations Environmental Programme (2002) Global MercuryAssessment, http://www.chem.unep.ch/MERCURY/Report/GMA-report-TOC.htm

AN40992_E 11/10C


Thermo Fisher Scientific (Ecublens)SARL, Switzerland is ISO certified.







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www.thermoscientific.com©2010 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries.Specifications, terms and pricing are subject to change.Not all products are available in all countries. Please consult your local sales representative for details.

Key Benefits• The Thermo Scientific iCE 3000 Series Atomic AbsorptionSpectrometers offers both flame and furnace capabilitiesfor precise and accurate analyses at parts per million andparts per billion levels

• Analysis of nutritional and toxic elements in rice productsis accurately determined with optimized methods

• The wizard-driven Thermo Scientific SOLAAR softwareallows quick and easy optimization for both flame andfurnace analyses.

SummaryThe Thermo Scientific iCE 3000 Series Atomic AbsorptionSpectrometers are the ideal tool for the accurate and rapiddetermination of multiple trace elements in rice products.Flame atomic absorption can be used as a fast screening toolfor the analysis of nutritional elements such as copper,manganese and zinc, while graphite furnace atomicabsorption can be used for the accurate determination oftoxic elements such as cadmium and lead. Simple samplepreparation and easy method optimization provide a rapidand effective solution for accurate and reliable analysis atminor and trace levels.

IntroductionRice is the second most prevalent cereal crop in the worldwith an annual global production of approximately 600million tons. It is the staple food of most Asian countries,with a daily consumption per person of between 200 and400 g. Trace elemental analysis of this crop and its productsis therefore important on an essential, nutritional andtoxicological level. The analysis of heavy metals is ofparticular relevance to human health following numerousincidents such as the mass cadmium poisoning of hundredsof people in the Toyama Prefecture, Japan. During the early20th Century, cadmium was released into the Jinzu River bymining companies in the mountains. The river water wasused to irrigate rice fields and cadmium was subsequentlyabsorbed by the growing rice. The effect on local peoplewas softening of bones, anemia, and kidney failure. Itbecame known as “Itai-Itai Byo”, a phrase adopted by thelocals to represent the pain caused by the poisoning. Globallegislation now exists to regulate the permissible levels ofcadmium in foodstuffs, with both China and the EU settingan upper limit of 0.2 mg/kg of cadmium in rice1,2. Suchlegislation has produced a requirement to monitor rice andother foodstuffs for trace metal content and this applicationnote discusses the analysis of copper, zinc, manganese,cadmium and lead in rice products by flame and furnaceatomic absorption for this purpose.

Method

Reagents

For Flame Analysis:

• Nitric acid, Trace analysis grade.

• Copper, manganese and zinc master standards, 1000mg/l.

• Multi-element standards prepared at 0, 0.5, 1, 2 and 5ppm copper, manganese and zinc using master standards.Diluted to volume with 1 % nitric acid.

For Graphite Furnace Analysis:

• Nitric acid, Trace analysis grade.

• Cadmium and lead master standards, 1000 mg/l.

• Cadmium standard prepared at 5 ppb using masterstandard. Diluted to volume with 1 % nitric acid.

• Lead standard prepared at 10 ppb using masterstandard. Diluted to volume with 1 % nitric acid.

• Furnace matrix modifier: ammonium nitrate, 20 μg in 10μl injection for cadmium, 50 μg in 10 μl injection forlead.

All standards and reagents from Fisher Scientific,Loughborough, UK.

Key Words

• Atomic Absorption

• Essential Elements

• Flame


• Rice

• Toxic Elements

ApplicationNote: 43019 Determination of Trace Elements in Rice

Products by Flame and Graphite FurnaceAtomic Absorption SpectrometryDr Hazel R. Dickson, Applications Specialist, Thermo Fisher Scientific, Cambridge, UK

Sample Preparation Three samples were analyzed: rice flour CRM (IRMM-804, LGC, Teddington, UK) and two samples of retailproducts from a local supermarket, rice flour and wholewhite rice. Samples were dried for 12 hours at 85 oC. Thesamples were cooled and portions of approximately 0.25 gwere accurately weighed and transferred to microwavedigestion vessels. 4 ml nitric acid was added to each vesseland left uncovered for 1 hour. A further 4 ml nitric acidwas added to each vessel, the vessels sealed and samplesdigested in a high pressure closed microwave digestionsystem, by ramping over 20 minutes to 170 oC. Sampleswere left to cool before being made up to 250 ml withdeionized water for cadmium analysis. Duplicate sampleswere prepared for the analysis of copper, lead, manganeseand zinc (from the same sample) with the digests made upto 50 ml with deionized water.

A spiked sample of the supermarket rice flour wasprepared to assess the sample preparation and subsequentanalysis of cadmium and lead by graphite furnace. Spikeswere added to obtain a final concentration approximately75 % of the CRM rice flour standard.

Results and Discussion

Flame: Copper, Manganese and Zinc Copper, manganese and zinc were analyzed by flameatomic absorption as these elements can be found asnatural constituents in soils and water, therefore detectionwithin the low mg/kg (ppm) range was required. Thetransverse and lateral burner position and the impact beadwere manually optimized using a 5 ppm copper standardprior to analysis. Burner height and fuel gas flow wereoptimized for each element using the Optimize Gas Flowand Burner Height Wizard in the SOLAAR software, asshown in Figure 1. This allowed quick and easy methoddevelopment with optimized parameters enteredautomatically into the analytical method.

Figure 1: Gas Flow and Burner Height Optimization Wizard.

The samples prepared to total volume of 50 ml wereanalyzed for copper, manganese and zinc. Each standardand sample was analyzed in triplicate using the fast re-sampling option. A continuous signal was measured for 4seconds for each resample. The total analysis duration,including optimization, calibration and analysis of sampleswas 25 minutes. This included a 5 point calibration andanalysis of the three samples for each element (Cu, Mnand Zn). Calibration curves for copper, manganese andzinc are shown in Figure 2.

Expected Measured Percentage Method Detection CharacteristicConcentration Concentration Recovery (%) Limit (mg/kg) Concentration

(mg/kg) (mg/kg) (mg/kg)

Copper

CRM 0.013 0.012 108.3

Rice Flour 0.007 0.0042 0.0646

Whole Rice 0.014Manganese

CRM 0.163 0.162 100.6

Rice Flour 0.038 0.0379 0.0102

Whole Rice 0.026Zinc

CRM 0.110 0.111 99.1

Rice Flour 0.091 0.0019 0.0187

Whole Rice 0.063

Table 1: Table of results and percentage recoveries of copper, manganese and zinc in rice products. Method Detection Limits and CharacteristicConcentrations shown are based on an initial mass of 0.25 g sample.

Figure 2: Calibration curves for the determination of copper, manganese andzinc in rice products.

Comparisons to the CRM expected concentrationwere made to assess the suitability of the method. Resultsfor the CRM, rice flour and whole rice are shown in Table 1, along with the method detection limits (MDLs)and characteristic concentrations (CCs) determined usingthe automated Instrument Performance Wizard in theSOLAAR software.

Furnace: Cadmium and LeadAs toxic elements with no nutritional benefit, detection ofcadmium and lead was required. As this was at trace level,graphite furnace atomic absorption was selected as theappropriate analysis technique. While a longer analysistime is required per sample, the use of the integratedautosampler allowed samples to be run unattended.Ammonium nitrate matrix modifier was used for both theanalysis of cadmium and lead. A working volume of 20 μlwas used for standard and sample injection, with anadditional 10 μl aliquot of matrix modifier added in acombined wet injection. 20 μg of ammonium nitrate wasadded for cadmium and 50 μg for lead. Graphite FurnaceTeleVision (GFTV) was used to observe injectiondeposition and the drying phase. This unique feature ofthe iCE 3000 Series Atomic Absorption Spectrometersallows direct visualization of the inside of the cuvette,displaying a high resolution image on the PC monitor forenhanced method development. The Optimize FurnaceParameters Wizard in the SOLAAR software was used tooptimize the ash and atomize phases. Zeeman backgroundcorrection was selected for all analyses to eliminate theeffect of potential structured background interferences.Furnace parameters for cadmium and lead are shown inTable 2:

Calibrations within the range 0-5 ppb for cadmium and 0-10 ppb for lead were obtained using the master standards.Standards were automatically diluted using the fixedvolume standard preparation option in the SOLAARsoftware as shown in Figure 3:

Figure 3: Sampling conditions for the analysis of cadmium and lead in riceproducts.

The CRM was analyzed to assess the suitability of themethod, followed by the rice flour and whole rice. Spikedrice flour was also analyzed to assess recoveryperformance of the method. Three repeats of eachstandard and sample were analyzed. The calibration linegenerated by the SOLAAR software for lead is shown in Figure 4, with a correlation coefficient of 0.9957. Resultsfor the CRM, rice flour and whole rice are shown belowin Table 3 along with the method detection limits (MDLs)and characteristic concentrations (CCs) determined usingthe automated Instrument Performance Wizard in theSOLAAR software. Cadmium and lead were not detectedin either of the retail products displaying compliance withcurrent international regulations.

Figure 4: Calibration line for the analysis of lead in rice products.Phase Temp oC Time / s Ramp oC/s

1: Drying 100 Cd, 115 Pb 30 10

2: Ashing 700 Cd, 1000 Pb 20 150

3: Atomizing 1300 Cd, 1500 Pb 5 Cd, 3 Pb n/a

4: Cleaning 2500 3 n/a

Table 2: Furnace parameters for the analysis of cadmium and lead in riceproducts.

Conclusion The results demonstrate the ease with which the ThermoScientific iCE 3000 Series Atomic AbsorptionSpectrometers can be used for the multi element analysisof rice products. Flame atomic absorption was used as afast analysis tool for the determination of copper,manganese and zinc. Detection limits were below 5 ug/kgfor copper and zinc and below 40 ug/kg for manganese.Graphite furnace atomic absorption was used as anaccurate analysis tool for the determination of cadmiumand lead, with excellent detection limits of 0.03 and 0.2ug/kg obtained respectively, easily ensuring regulatorycompliance.

A Certified Reference Material was used to verify boththe flame and furnace methods with excellent recoveriesobtained The ease of use of the system is exemplified withthe many automated wizards which enable fast accurateresults regardless of analyst experience. The ThermoScientific iCE 3000 Series Atomic AbsorptionSpectrometers therefore provide an ideal solution for theaccurate and rapid multi element determination of minorand trace elements in rice at parts per million and partsper billion concentrations.

References1. Peoples Republic of China, FAIRS Product Specific Maximum Levels of

Contaminants in Food 2006

2. Commission Regulation (EC) No. 1881/2006 of 19 December 2006 settingMaximum Levels for Certain Contaminants in Foodstuffs


AN43019_E 11/10C

Measured Expected Percentage Method Detection CharacteristicConcentration Concentration Recovery (%) Limit (μg/kg) Concentration

(mg/kg) (mg/kg) (μg/kg)

Cadmium

CRM 1.5 1.43 +/- 0.07 105 %

Rice Flour <DL 0.0303 0.0600

Spiked Rice Flour 1.06 1.00 106 %

Whole Rice <DL

Lead

CRM 2.03 2.00 +/- 0.07 102 %

Rice Flour <DL 0.1960 0.7119

Spiked Rice Flour 1.24 1.20 103 %

Whole Rice <DL

Table 3: Table of results and recoveries of cadmium and lead in rice. MDLs and CCs shown are based on an initial mass of 0.25g sample.









www.thermoscientific.com©2010 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries.Specifications, terms and pricing are subject to change. Not all products are available in all countries. Please consult your local sales representative for details.

Key Words

• AtomicAbsorption


• Zeeman

• Cadmium

• Chocolate


Key Benefits

• The Thermo Scientific iCE 3500 Atomic AbsorptionSpectrometer provides a simple and uncomplicatedsolution for the analysis of trace elements

• The wizard-driven Thermo Scientific SOLAAR Softwareallows quick and easy optimization and method development.

• Analysis by graphite furnace is easy with GraphiteFurnace TeleVision (GFTV), which allows viewing of thesample inside the cuvette.

SummaryThe Thermo Scientific iCE 3500 Atomic AbsorptionSpectrometer is the ideal tool for the simple and easyanalysis of cadmium in chocolate. A straight forwardsample preparation procedure combined with a fullyoptimized analysis method resulted in accurate detectionwell below current recommended limits for theconcentration of cadmium in foodstuffs.

IntroductionCadmium is a heavy metal used in a variety ofapplications, such as steel plating, as a pigment in plasticsand glasses, and in the production of batteries. Theseindustrial activities are the main route through whichcadmium is released into the environment where itaccumulates in water and soil, and subsequently plants,animals and fish through uptake and ingestion. One of themain routes of human exposure to cadmium is thereforethrough the ingestion of foodstuffs.

The provisional tolerable weekly intake (PTWI) ofcadmium is currently 7 μg/kg body weight, however therecommendation is to limit cadmium intake as it offers nonutritional benefit. Typical maximum levels of cadmium infoodstuffs are currently between 0.05 – 0.2 mg/kg wetweight.1-3 Excessive cadmium consumption can causenausea, gastrointestinal pain, softening of bones andkidney damage. Cadmium accumulates within the kidneysand can eventually cause renal failure.

Chocolate and chocolate-based sweets and candies arecommon treats, snacks, or gifts for children and adultsalike. The main ingredients in chocolate consist of cocoa,milk and fats, each of which is a potential source ofcadmium. The determination of cadmium levels inchocolate is therefore an important issue for chocolateconsumers and manufacturers around the globe.

Method

Reagents

• Nitric acid, 69 %, trace metal grade

• Hydrogen peroxide, > 30 % w/v, trace metal grade

• 1000 mg/l Cadmium master standard used to preparesub-standards

• Ammonium nitrate

All standards and reagents purchased from Fisher Scientific.

Sample PreparationApproximately 0.3 g pieces of chocolate (popular globalbrands of milk and dark variety) were accurately weighedand transferred to microwave digestion vessels. 7 ml ofnitric acid and 1 ml of hydrogen peroxide were added andleft to stand for 5 minutes, before the vessels were sealedand samples digested in a high pressure microwavedigestion system by ramping to 200 °C over 10 minutes.Samples were maintained at 200 °C for twenty minutesbefore being allowed to cool. The contents of the vesselswere then quantitatively transferred to 100 ml volumetricflasks with deionised water and made up to a final volumeof 100 ml.

(It is recommended to leave the samples in the sealedvessels for several hours to cool before transfer of thecontents to ensure the minimal loss of volatile elements,and to carry out multiple rinses of the vessels to ensure alldigested material is transferred to the volumetric flask).

Standard and Reagent PreparationA 1 mg/l cadmium sub-standard was prepared in deionisedwater for spiking of samples prior to digestion. The 1 mg/lsub-standard was then used to prepare a 10 μg/l sub-standard for calibration. The 10 μg/l sub-standard was madeup in 7 % nitric acid and 1 % hydrogen peroxide to matrixmatch to the digested samples. Blank and diluent were alsoprepared at 7 % nitric acid and 1 % hydrogen peroxide. Amatrix modifier was prepared at 2 g/l to allow deposition of20 μg of ammonium nitrate in a 10 μl aliquot.

The Analysis of Cadmium in Chocolate byGraphite Furnace Atomic AbsorptionSpectrometryDr Hazel R. Dickson, Applications Specialist, Thermo Fisher Scientific, Cambridge, UK.

Furnace MethodFurnace temperature parameters are shown in Table 1:

Phase Temperature / °C Time / s Ramp / °C/s

Dry 110 30 10

Ash 400 20 150

Atomize 1300 3 0

Clean 2500 3 0

Table 1: Furnace parameters for the analysis of cadmium in chocolate.

The optimize furnace parameters wizard in theSOLAAR software was used to determine the mostsuitable temperatures for drying and ashing of the digestedchocolate samples. Graphite Furnace TeleVision (GFTV)was used to optimize the position of the injection capillaryand to observe the deposition of the sample into thecuvette. The 10 μg/l cadmium solution was used as themaster standard for the method. The autosampler wasprogrammed to automatically generate calibration standards at 2, 4, 6, 8 and 10 μg/l. All samples, blanksand standards were injected at a constant fixed volume of10 μl, alongside an additional aliquot of 10 μl of matrixmodifier into an electrographite cuvette. Cadmium wasanalyzed at 228.8 nm and Zeeman background correctionwas used throughout. Peak areas were measured for theproduction of the calibration and subsequentdetermination of the sample concentrations.

Results and DiscussionA segmented fit curve was used for generation of thecalibration for the analysis of cadmium in chocolate. Thecalibration curve for cadmium is shown in Figure 1.

Figure 1: Calibration curve for the analysis of cadmium in chocolate.

Spiked samples were prepared to evaluate the recoveryof cadmium. This was done by adding 0.5 ml aliquots ofthe 1 mg/l cadmium standard to samples of chocolate andthen preparing and analyzing using the proposed method.(0.5 ml of 1 mg/l cadmium results in addition of 5 μg/l tothe final sample).

Results for the analyzed samples are shown in Table 2

SAMPLE MEASURED CONCENTRATION IN CALCULATED SPIKEDCONCENTRATION / ORIGINAL SAMPLE / RECOVERY / %μg/l mg/kg �

USA Origin, 0.030 0.010Milk

USA Origin, 5.095 101Milk, Spiked

UK Origin, 0.038 0.012Milk

UK Origin, 5.182 103Milk, Spiked

USA Origin, 0.124 0.042Dark

USA Origin, 4.761 93Dark, Spiked

Table 2: Results for the analysis of cadmium in chocolate following analysisby graphite furnace atomic absorption spectrometry.

Cadmium was detected in small amounts in all threechocolate samples, with the maximum calculated at 0.04mg/kg. However, all samples fell below typical currentlegislation for the recommended maximum levels ofcadmium in foodstuffs.

Spiked recoveries were performed on the threeanalyzed samples and were all found to be good. Inaddition, the method detection limit and characteristicconcentration were calculated using the check instrumentperformance wizard in the SOLAAR software. Themethod detection limit was found to be 0.029 μg/l and thecharacteristic concentration 0.060 μg/l.

ConclusionCadmium in chocolate was analyzed following a simpledigestion procedure, and matrix matched standards wereused to accurately determine cadmium concentration.Cadmium was found in all three samples but was below therecommended limits for cadmium in foodstuffs. The methodwas verified against spiked recoveries and the methoddetection limit was found to be 0.029 μg/l. Wizards in theSOLAAR software were used for uncomplicated methoddevelopment. The iCE 3500 Atomic AbsorptionSpectrometer provides a simple, easy and accurate tool forthe analysis of cadmium in foodstuffs.

References1. Codex General Standard for Contaminants and Toxins in Foods,

Codex Stan 193-1995, Rev.3-2007

2. Peoples Republic of China, FAIRS Product Specific Maximum Levels of Contaminants in Foods 2006

3. Commission Regulation (EC) No 1881/2006 of 19 December 2006: Setting Maximum Levels for Certain Contaminants in Foodstuffs


AN43034_E 12/10C

(Fact: For an average adult of weight 70 kg,approximately 12 kg per week of the dark chocolateanalyzed in this experiment would need to beconsumed to exceed the PTWI. However – this wouldnot be advisable for a balanced and healthy diet!)









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Product Specifications

• Unique dual atomizer design enablessafe, software-controlled switchingbetween flame and furnace analysis witha single mirror movement

• High precision, double beam optics,combined with an Echelle monochromatorproduce stunningly low detection limitsand incredible analytical stability

• New universal 50 mm titanium burnerwith improved solids capability increasesthe efficiency and accuracy of your flameanalysis

• Unique Quadline deuterium backgroundcorrection with guaranteed performanceas standard

• Superior furnace vision system includedas standard improves efficiency andsimplifies method development byproviding a high definition, real timevideo of the inside of the cuvette

• Improved efficient design minimises thefootprint of the instrument and ensuresthat day-to-day analysis and maintenanceis simple

• Enhanced, user-friendly software andcomprehensive Wizard driven interfaceguides you through every aspect of ananalysis

• Safety comes as standard with integratedsoftware and hardware safety featuresand automatic gas control

• Simple installation and operation of thepre-aligned furnace and autosamplermodule

• Choose a deuterium only furnace, or aZeeman AND deuterium backgroundcorrection furnace, for the ultimate inflexible, interference free analysis

• Unique, state-of-the-art extended lifetimecuvettes (ELCs) provide vastly extendedlifetimes, improving efficiency and savingyou money

• Security software and validation packagesallow complete 21 CFR part 11, GLP andGALP compliance (optional upgrades)

The Thermo Scientific iCE 3500Atomic Absorption SpectrometerHigh performance, dual atomizer, double beam AA Spectrometer

The Thermo Scientific iCE 3500Atomic Absorption Spectrometeris a unique, dual atomizerinstrument that providesunrivalled levels of performancein an innovative, user-friendlypackage.


e l e m e n t a l a n a l y s i s

The refreshingly different iCE 3500 Atomic AbsorptionSpectrometer provides unrivalled performance, flexibility andsimplicity. A new, innovative burner design improvessolids capacity and accuracy during flame analysis.Superior optics, innovative design and guaranteedbackground correction ensures unrivalled analyticalperformance. The unique dual atomizer design allowsautomatic, efficient and safe switching between flameand furnace analysis with no user intervention. The userfriendly, Wizard driven Thermo Scientific SOLAARSoftware guides new users through every aspect of ananalysis and adds extra functionality for experienced users.

Unrivalled flame sensitivity is achievedby high efficiency nebulization into a fullyinert spray chamber with impact bead andspoiler. The new finned 50 mm universaltitanium burner ensures exceptionalatomization even with the most difficultsamples. The fully automatic gas box usesbinary flow control for safe, reliable andrepeatable flame conditions.

All critical parameters can beautomatically optimized if required – burnerheight, gas flows and even opticalinstrument parameters.

The iCE 3500 Atomic AbsorptionSpectrometer accepts the Thermo ScientificGFS35 and the GFS35Z Integrated GraphiteFurnace and Auto-sampler Module. Offer theultimate in detection limits with minimuminterferences. The GFS35Z provides a choiceof Zeeman or Deuterium backgroundcorrection for guaranteed performance.Dynamic optical temperature feedbackensures accurate heating rates of up to3000 ºC per second, regardless of cuvetteage. The unique GFTV furnace vision systemis provided as standard, giving you theultimate in effective and easy furnacemethod development.

The GFS35/GFS35Z offers unrivalledgraphite furnace automation. Huge capacityand multiple solution preparation facilitiescater for all needs. With automatedash/atomize temperature optimization,autosampler loading guides and thebackground correction options, furnaceanalysis has never been easier. Theautosampler remains permanently inalignment with the furnace completelyeliminating the need to re-align the probeand furnace head.

Thermo Fisher Scientific are the onlysupplier offering Extended Lifetime Cuvettes(ELC) with up to 10 x more lifetime thanalternatives. Couple this with features suchas pre-heated cuvette injection, coolingwater temperature compensation and fastfurnace operation, then you know you aremaking a safe choice.

The Thermo Scientific SOLAAR Softwarepackage is both intuitive and easy to use.Extensive wizards are able to guide the userthrough various operational proceduresmaking start-up a simple and quick process.

Additional information on theoperational conditions for any elementalanalysis is available in the help text andcookbook. Application tips for samplepreparation, matrix modifiers and many otherimportant factors are also available withinThe Thermo Scientific SOLAAR software.

In addition, a full range of accessoriesare available to permit flame auto-sampling,intelligent dilution, vapour analysis andvalidation.

Technical Specification

The Thermo Scientific iCE 3000 SeriesAtomic Absorption Spectrometerscomprising of:-

iCE 3300 Atomic Absorption Spectrometer:

Single flame atomizer AAS with fullyautomatic gas box


Single furnace atomizer AAS with Zeemanand D2 background correction


Dual flame and furnace system AAS withStandard or Zeeman furnace option

The iCE 3000 Series Atomic AbsorptionSpectrometers provides an unrivalled rangeof solutions from Thermo Fisher Scientific;the award winning innovator in AtomicAbsorption Spectrometry.


PS40889_E 11/10C

Optics Double beam

Monochromator Echelle type

Lamp Carousel 6 Lamp Coded, auto-aligning

Photomultiplier Wide range (180 nm to 900 nm)

Flame Atomiser Universal system (uses 50 mm Finned Ti burner)

Furnace Atomiser options GFS35 or GFS35(Z) combined module

Furnace Vision System As standard

Background Correction Guaranteed Quadline deuterium or AC Zeeman systems

Gas Management Automatic binary control

PC Software Included as standard

Security Package Optional

Validation Package Optional

Thermo Electron Manufacturing Ltd(Cambridge) is ISO Certified.

www.thermoscientific.com©2010 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries. Specifications, termsand pricing are subject to change. Not all products are available in all countries. Please consult your local sales representative for details.

Africa-Other +27 11 570 1840Australia +61 3 9757 4300Austria +43 1 333 50 34 0Belgium +32 53 73 42 41Canada +1 800 530 8447China +86 10 8419 3588Denmark +45 70 23 62 60

Europe-Other +43 1 333 50 34 0Finland /Norway/Sweden

+46 8 556 468 00France +33 1 60 92 48 00Germany +49 6103 408 1014India +91 22 6742 9434Italy +39 02 950 591

Japan +81 45 453 9100Latin America +1 561 688 8700Middle East +43 1 333 50 34 0Netherlands +31 76 579 55 55New Zealand +64 9 980 6700Russia/CIS +43 1 333 50 34 0South Africa +27 11 570 1840

Spain +34 914 845 965Switzerland +41 61 716 77 00UK +44 1442 233555USA +1 800 532 4752

The Thermo Scientific GFTV replaces obsoletesystems with a simple, precise and powerfulalternative. A state-of-the-art camera displayshigh definition, crystal clear video within theThermo Scientific SOLAAR software. Thishighly advanced, user-friendly system greatlysimplifies furnace method development. Itenables the user to fully optimize their analysisto significantly improve productivity.

With the Thermo Scientific GFTV it is nowpossible to easily and accurately align theauto-sampler and adjust the sample injectiondepth. This dramatically decreases the timetaken to optimize the instrument and ensuresuniform and repeatable sample introduction.

During a furnace analysis the sampledrying can be observed. This enables the userto confidently adjust the furnace program,guaranteeing perfect drying conditions and thehighest possible precision. Viewing the sample-ashing phase helps ensure efficient matrixremoval and reveals the presence of anyresidue. The ability to monitor the entirefurnace cycle ensures that the optimumanalytical conditions can be selected to providethe most accurate results.

The high-definition video image displayedwithin the SOLAAR software is fullycustomizable and may be recorded or stored forfuture use. These recorded files are invaluableas training tools for new users, and can beused as evidence for regulatory purposes.




Thermo Scientific Graphite FurnaceTelevision (GFTV)Fully optimize your system with this perfect methoddevelopment tool

The Thermo Scientific GraphiteFurnace Television (GFTV) makesfurnace analysis refreshinglyeasy. GFTV enables precise andrepeatable results every time.

The Thermo Scientific Graphite Furnace Television (GFTV) is therevolutionary development in furnace analysis. This unique furnacevision system provides essential visual feedback on events occurringwithin the cuvette during sample analysis. This information haspreviously been difficult or impossible to obtain using traditionalmirror-based viewing techniques.


The following examples show how GFTV can help improve method development and thequality of results. The ability to watch the sample during the furnace program revealsessential information, which will result in superior analytical methods.

Examples

Using Platform Cuvettes:

• Some applications exhibit chemicalinterference effects, which may be partiallyovercome using a platform cuvette

• Injection depth can be easily checked andinjection process monitored

• The drying and ash phases can be viewedand the temperature programme adjustedto give the best analytical results

Injection Correct:

• Sample is deposited uniformly into aconfined area of the cuvette

• Spreading of sample is minimal• Injection process and therefore results

will be reproducible

Injection depth too low:

• Tendency for the sample to be forced upthe tube walls and to spread along theinside of the tube

• Injection process will not be reproducible,which will have a negative effect on theanalytical precision

• May damage the capillary tip which willnegatively affect future injections

Injection depth too high:

• Sample may splash as it drops onto thetube surface

• Surface tension may cause the sample toremain on the injection capillary

• Sample could be deposited around theinjection port when the capillary isremoved

• If the injection depth is too high this maylead to inaccurate results

The Thermo Scientific GFTV is the perfect method development and training tool. Itsflexibility, user-friendly interface and high quality video make method optimization simple.GFTV is a standard feature on the Thermo Scientific iCE 3400 and iCE 3500 AtomicAbsorption Spectrometers and can also be utilized on the iCE 3300 as an additional option.

PS40141_E 11/10C







www.thermoscientific.com©2010 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries. Specifications, terms and pricing are subject to change. Not all products are available in all countries. Please consult your local sales representative for details..


The Thermo Scientific iCE 3000 SeriesAtomic Absorption Spectrometers combinedwith the VP100 accessory enables you toachieve detection limits comparable to anICP-MS, but at a fraction of the cost.• Fast Analysis

Analysis of a typical sample is possible inless than 60 seconds. The VP100’s uniquecontinuous flow design means that samplewash-out time is reduced and samplethroughput is increased.

• Superb performanceAn iCE 3000 Series Atomic AbsorptionSpectrometer and VP100 accessory cangive you detection limits in the parts pertrillion range for several important hydrideand cold vapor forming elements: As, Se,Ge, Bi, Pb, Te, Sb, Sn, and Hg.

• Fully customizableThe VP100 can be optimized to meet theexact needs of the user. With simple,software-controlled adjustments you willquickly be able to find the perfect balanceof speed and sensitivity for your analysis.

• User-friendlyAll the tubing and connections on theVP100 are color-coded, making set-up ofthe accessory quick and easy. The uniquedesign removes the need for switching-valves and makes the analysis simpler forthe user. The VP100 is entirely controlledby the Thermo Scientific SOLAAR Software,so any adjustments to instrumentparameters can be made using SOLAAR’sintuitive user interface.

• Easy to maintainThe unique continuous flow systemensures self-cleaning of the VP100. Theonly maintenance required is to wash thesystem with de-ionized or distilled waterwhen an analysis is complete.

VP100 Continuous Flow VaporGeneration SystemIncredible performance in a user-friendly package

The unique VP100 continuous flowvapor generation system offersexceptional performance, fastsample analysis and easy methoddevelopment. The system achievessuperb detection limits for hydrideand cold vapor forming elementsincluding mercury and arsenic.



Principle of OperationHydride generation AAS uses a chemicalreaction to create volatile metal-hydridespecies which can be analyzed in the vaporphase. Suitable liquid reagents are mixedwith samples in a reaction zone to formhydride vapor. The vapor is separated fromthe liquid mixture in a gas-liquid separatorand carried to an atomization cell which canbe heated if required. When heated, thehydride decomposes to release atoms, whichare then measured by atomic absorption. Thecell can either be heated using the air-acetylene flame or by an electrically heatedfurnace. For the analysis of mercury, noheating is required as the chemicals usedform elemental mercury, which passes as avapor to the cell.

PerformanceThe VP100 vapor generation accessorycombined with the iCE 3000 Series AtomicAbsorption Spectrometers enables part pertrillion level detection of hydride and vapor-forming elements. Table 1 gives typicaldetection limits for some commonly analyzedelements. These figures are comparable withthose obtained via ICP-MS. In addition, thefigures are likely to be more reliable forarsenic and selenium due to the removal ofcommon ICP-MS interferences for thoseelements.

Characteristic DetectionConcentration Limit

µg/L µg/LAntimony 0.29 0.06Arsenic 0.2 0.05Bismuth 0.36 0.1Mercury 0.26 0.06Selenium 0.7 0.15Tellurium 0.46 0.1Tin 0.38 0.2

Table 1. Typical detection limits achievable withthe VP100 Vapor Generation Accessory and iCE3000 Series Atomic Absorption Spectrometers

Intelligent DesignThe VP100 has been designed to make vaporanalysis as fast, simple and sensitive aspossible. A unique, continuous flow designreduces wash-out times and eliminates carry-over. The gas-liquid separator is made fromadvanced materials that are completely inertto all reagents to reduce interferences andprolong its lifetime. All connections on theVP100 are color-coded to make set-up andmaintenance simple.

PrecisionOur use of state-of-the-art, mass-flowcontrolled gas supplies means that the VP100is not reliant upon older, less accurate gassystems. This means that we can preciselycontrol the carrier gas flow through theVP100. The accurate and precise mass-flowcontrolled system provides exceptional long-term stability, ensuring that gas flow rates donot change even if laboratory temperature orpressure varies.

EC90The electrically heated atomization cell(EC90) can be used in conjunction with theVP100. It provides better sensitivity andlower running costs compared to standardflame heating.

Specialized measurement kitsTo ensure that the best performance isachieved for each of the hydride-formingelements we have included two differentmeasurement cells. The T-cell is used for As,Se, Ge, Bi, Pb, Te, Sb and Sn. This silica cellis incredibly temperature-resistant, whichmeans that it can be heated to the optimaltemperatures to degrade the metal hydridesformed in the VP100. Mercury is analyzedusing a special mercury cell, specificallydesigned with a longer path length to allowyou to achieve the lowest possible detectionlimits.

Flexible analysisThe VP100 parameters can be adjusted usingthe software to allow you to fully optimizeyour analysis. Carrier gas flow and pumpspeed can be varied independently, whichallows you to find the perfect balancebetween speed and sensitivity.

Graph 1: Pump speed vs Absorbance andStabilization Time

Graph 2: Gas Flow vs Absorbance and Time

Conclusion

• The VP100 is a powerful tool for themeasurement of hydride-forming elements,achieving exceptionally low detectionlimits

• Its unique design provides fast, repeatableand accurate analyses

• The VP100 is fully controlled by theThermo Scientific SOLAAR software,eliminating manual optimization andmaking method development quick anduser-friendly


Absorbance Stabilization Time

Absorbance Stabilization Time

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Some metallic elements are essential to the health and well being of the human body as they play an important role in basic functions. Examples of these include phosphorus,

which is needed for muscle and tissue growth, and calcium, which is critical for normal cell operation. Minute amounts of zinc and manganese are required for hormone production and enzyme function. The absence or excess of these elements in the diet would result in the body not functioning in a normal and healthy way. Other elements such as arsenic, mercury, and lead are toxic and offer no physiological benefit. Entry of these elements into the body is usually via ingestion of food that has been contaminated due to pollution of the environment where the food is produced.

Food and beverage suppliers and manufacturers, therefore, have a responsibility to know what is in the food they are supplying to consumers.

Food Safety and the MediaRecent years have seen a change in the availability of research and information relating to food and public health. Such research is no longer only visible to scientific researchers through academic literature but is becoming more and more visible to the general public through news websites, magazine articles, and online blogs and social networking sites — for example, the U.S. Food and Drug Administration now announces product recalls though the

Hazel Dickson

Atomic absorption (AA) has been used worldwide for decades, offering solutions in numerous appli-cation areas, from clinical to pharmaceutical and environmental. The combination of flame, furnace, and vapor techniques allows the analysis of over 60 elements and covers a wide analytical range, from parts per million (ppm) down to sub parts per billion (ppb). While viewed as a mature technol-ogy, the simplicity and affordability of AA, combined with its sensitivity and accuracy, still makes it an attractive choice for laboratories today and the market continues to grow. In particular, the past decade has seen a significant increase in the use of AA in the food and beverage industry. The consumption of foodstuffs is the major route for trace elements to enter the body, and as scientific understanding and consumer awareness grows, so too does the field of trace elemental analysis and food safety.

Atomic Absorption: Feeding the Food Safety Market

Atomic Perspectives

July 2010 Volume 25 Number 7 www.spectroscopyonline.com

http://www.spectroscopyonline.com

real-time information network Twitter. In addition, the past several months have seen a wealth of articles appearing in the general public news relating specifically to trace elements in foodstuffs, including antimony and arsenic in fruit juice, lead in cocoa products, and tin in canned foods. With an ever-increasing public and con-sumer awareness, the demands placed on food analysis and testing laboratories has reached an all-time high.

Regulations and GuidelinesGlobal legislation exists to protect con-sumer health by controlling contami-nants and toxins in foodstuffs. To aid and elaborate food safety legislation, the CODEX Alimentarius was established by the Food and Agriculture Organisation (FAO) of the United Nations and World Health Organisation (WHO) in 1963 and provides internationally recognized stan-dards, guidelines, and codes of practice. The elements to which the greatest number of standards and controls are applied are arsenic, cadmium, lead, mercury, and tin. The maximum levels of toxic elements in foodstuffs is typically set around 0.1 mg/kg, but this can vary depending upon country or region, food type, and typical consumption (1).

Regulations and guidelines on labeling and nutritional content also cover a variety of trace elements. When a nutrient decla-ration is applied, foodstuffs that provide more than 5% of the nutrient reference value (recommended daily allowance) per 100 g are usually stated (2). Nutritional ele-ments include calcium, magnesium, iron, zinc, iodine, copper, and selenium. Forti-fied products such as iron-enriched cereals and calcium-enriched yogurts and dairy drinks must also quantify fortification claims on the label. Labeling of sodium on foodstuffs is usually included as an element listed in the main nutritional informa-tion. Sodium comes from not only sodium chloride but also many other additives and preservatives, particularly in foods requir-ing water reconstitution, including mono-sodium glutamate, sodium saccharin, and sodium bicarbonate — baking soda. In fact, over 75% of sodium consumed in a typical diet comes from manufactured and processed foods, rather than the salt added during cooking or at the dinner table (3).

A Key Player in Food SafetyThe prominence of food safety in the global analytical community has revealed

atomic absorption (AA) as a key player in the analysis of trace elements in foodstuffs. An established technique of several de-cades, AA is proving to be the technique of choice for those laboratories requir-ing dedicated analysis on a regular basis. Analytical laboratories inherently demand robust and reliable methodologies and in-strumentation. AA offers an ideal solution, providing excellent sensitivity, accuracy, and precision. In addition, advances in automation, through online sample dilu-tion and automated standard preparation, simplify routine tasks and offer increased productivity and sample throughput.

One of the fastest growing markets in food safety is China, mirrored by the continued growth of the Chinese Gross Domestic Product (GDP). The Food Safety Law, introduced in China in June 2009, which toughens penalties against manu-facturers of mislabeled or tainted food, and has raised the profile of food safety in this region significantly. This has resulted in a noticeable increase in the trace elemental analysis of foodstuffs. China is the world’s largest exporter of fruits and vegetables, with meat, fish, and cereals (such as rice) contributing significantly to the billion-dollar export market.

Feeding the Food Safety MarketAA is being used around the globe to en-sure laboratories meet the requirements for the analysis of trace elements in foodstuffs. As mentioned, the analysis of sodium in food is of great importance, with some

laboratories analyzing over 100 samples per day. Flame AA offers a simple, dedicated solution and, with the use of an intelligent on-line dilution system and autosampler, provides complete automation over several orders of magnitude. Flame and furnace systems also can be used as complemen-tary techniques for the analysis of multiple elements in the same sample. The global annual production of rice, the staple food of most Asian countries, is approximately 600 million tons. Flame AA can be used to analyze the essential elements in rice, such as manganese and zinc, while furnace AA can be used to ensure toxic elements such as cadmium and lead are below legislative limits (4). A major benefit of furnace AA is the small sample volume required for analysis. Typically, only a few microliters of sample are needed, allowing minimal dilu-tion on the original sample to achieve the very best detection limits.

The unique elemental properties of mer-cury can make it a difficult element to ana-lyze by standard flame and furnace meth-ods. However, by using a continuous flow system with online mercury reduction and cold vapor generation, detection limits in the parts per billion range can be achieved (5). This is comparable to the detection limits achieved with inductively coupled plasma–optical emission spectroscopy (ICP-OES), yet is a simple and economical solution, making it accessible for laborato-ries worldwide. The method has been used for the analysis of mercury in fish, which is yet another prominent global issue relating

Figure 1: Food analysis continues to be an important application of AA spectroscopy.

to trace elements in foodstuffs. Minamata Bay, located in the Kumamoto Prefecture, Japan, saw over 10,000 individual cases of mercury poisoning, following disposal of mercury-contaminated wastewater into the local river, however, it took several years before the effects were observed and the source of the contamination identified. Bioaccumulation of mercury in the marine food chain results in high levels in preda-tory fish (such as tuna), which can result in mercury poisoning in humans if such fish is consumed regularly.

Looking ForwardThe use of atomic absorption in the trace elemental food laboratory is likely to con-tinue into the future, even as legislative requirements tighten and lower detection limits are demanded. Flame, furnace, and vapor techniques, in combination with preparative accessories and automation provide versatile, robust, and reliable con-figurations for even the most challenging of applications. For those laboratories employing more than one trace elemental analysis technique, such as ICP-OES and

ICP-mass spectrometry (MS), AA still maintains a significant presence and is used for dedicated applications like so-dium or mercury, as a screening tool for unknown samples, or as a ready-to-go walk-up system for the analysis of single or urgent samples.

Atomic absorption is expected to main-tain a strong presence within food analysis laboratories, particularly within this tough economic climate. With reliable and robust technology, yet simple and affordable op-eration, atomic absorption will continue to feed the food safety market for years to come.

References(1) www.codexalimentarius.net(2) www.food.gov.uk/foodlabelling/(3) www.food.gov.uk/healthiereating/salt/(4) Application Note, “Determination of trace

elements in rice products by flame and graphite furnace AA,” Thermo Fisher Sci-entific.

(5) Application Note, “Accurate analysis of low levels of mercury in fish by vapor genera-tion AA,” Thermo Fisher Scientific.

Hazel Dicksoncurrently works as the AA Applications Chemist for Thermo Fisher Scientific in Cambridge, UK, with a par-ticular interest in food safety.

Hazel holds a first class degree in Chemistry with Study in Industry, obtained from the University of Sheffield, UK. She spent a place-ment year of her degree working as an analyti-cal chemist at GlaxoSmithKline, using MS for the structural characterization of pharmaceuti-cal compounds. She has also just finalized a PhD, focusing on the use of laser-based MS methods for the analysis of small molecules and elements in biological samples.

For more information on this topic, please visit:

www.spectroscopyonline.com

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#1-27978669 Managed by The YGS Group, 717.505.9701. For more information visit www.theYGSgroup.com/reprints.

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Food Safety Applications using Atomic Absorption Spectrometry

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