The word "chromatography" derives from the Greek "khròmatos" (color) and"graphia" (from gràpho "to write"), so it literally means "written in color". Itsorigins date back to the early 20th Century (1901-1903), when Russian botanist

Michail Semenovich Tswett filtered a solution of vegetable substances on a col-umn filled with calcium carbonate, as an adsorbent, and obtained a separation of

the colored pigments. Since then chromatography, in its different applications, hasundoubtedly proven itself as one of the most effective and widely adopted techniques for

qualitatively as well as quantitatively decomposing a mixture of components. All chromatographic techniques are based on the fact that every compound present in a mixture

interacts differently with the surrounding environment under the same conditions. Each separation system is determined by the competitive distribution of a component over a mobile

phase (vector fluid or eluent) and a stationary phase. Based on certain parameters, the various sub-stances migrate differently through the support and thus become separated.

Types of chromatography

Chromatographic techniques vary depending on the physical characteristics of the solute, eluent and stationaryphase which are used to achieve the separation. Overall, five types of chromatography can be identified:

1 Adsorption chromatography (L.S.C.)This technique is based on the adsorption of a solute on a polar adsorbent such as silica gel, alumina,diatomaceous earth, magnesium oxide and activated carbon or other compounds that have the same physicalproperties. The mechanism governing this kind of separation is the competition of the solute among the polargroups present on the surface of the stationary phase and the non-polar mobile phase.

2 Partition chromatography (L.L.C.)The principle behind this technique is based on the separation of a solute between two immiscible solvents,one of which is the "stationary phase" while the other is the "mobile phase".

Partition chromatography can be divided into:DIRECT OR NORMAL PHASE CHROMATOGRAPHY - if the stationary phase is more polar than the mobile phase;REVERSED PHASE CHROMATOGRAPHY - if the mobile phase is more polar than the stationary phase.

3 Ion exchange chromatographyIn ion exchange chromatography the surface area of the stationary phase is covered with SO3- / COO- /NH3+ ionic groups which can be exchanged with the ionic components of the solute. This exchange can becationic or anionic.In this case, the elution depends on the pH of the mobile phase.

4 Exclusion chromatography (GPC)Exclusion chromatography does not depend on the type of interaction between solute, stationary phase andmobile phase, but only on the size of the solute molecules in relation to the size of the stationary phase poreswhich act as a screen.Two components can be separated if their molecular weights differ by about 10%.

5 Affinity chromatographyAffinity chromatography is a newly applied method based on specific biochemical interactions between appro-priately modified stationary phases and molecules of the solute with special spherical or charge characteris-tics.

CHROMATOGRAPHY

34

Chromatographic techniques vary depending on:

a. Physical state of the mobile phase

- chromatography with liquid eluent or liquid chro-matography (LC);

- chromatography with gas eluent or gas chro-matography (GC).

In liquid chromatography the elution of a mixture maybe performed in two ways:

- Isocratic elution, using a single eluent andkeeping the flow constant;

- Gradient elution, using two or more eluentsmixed in percentages over time, stepwise, keep-ing the flow constant.

In gas chromatography, on the other hand, the parti-tion of a solute in gaseous or vapor phase is transport-ed by an inert gas through a packed or capillary col-umn. The gaseous phase, with an appropriately adjust-ed speed, transports the substance to be analyzed (ingaseous form) through the stationary phase. Since thestrength with which the stationary phase tends toretain different components varies, the distinct compo-nents of the sample will pass though the column at dif-ferent speeds and exit separately.

b. Presentation of the stationary phaseThe solid phase, which may be an active stationaryphase or simply a support, is contained in a column,and the column is defined as a:

- Packed columnif the column is filled with a finely subdivided solidsuch as chromatographic silica sand, brick dust orglass spheres, homogeneously covered with a liq-uid;

- Capillary column (or open-tubular column)if its interior walls are coated with the liquid. Thesecolumns are generally made of fused silica, with adiameter between 0.2 and 0.6mm and a lengthvarying from 15 to 50 meters. Compared to packedcolumns, capillary columns offer higher resolutionbut require longer analysis times.

- Support-coated open-tubular (SCOT) column is treated so as to form or deposit a porous orirregular layer on the surface before it is coveredwith the liquid phase.

Other chromatographic techniques to mention are:

Headspace gas chromatography (HSGC)This is an indirect chromatographic technique for quickdetermination of volatile compounds in liquids andsolids, in which the instrument parameters must be setto keep the sample container temperature constant.The operating principle of this technique is based onthe chromatographic analysis of the vapor phase inthermodynamic equilibrium above the sample enclosedin a sealed container.Under these conditions, the quantity of volatile compo-nents present in the gaseous phase above the sample(in the headspace) is higher but proportional to theirconcentration in the sample.Thus, through appropriate calibration, the concentra-tion of volatile components in solution can be deter-mined by analyzing a part of the gaseous phase.

Thin-layer chromatography (TLC)This technique uses a liquid mobile phase and a solidstationary phase spread in a thin layer on a support,usually a glass plate.Used as an alternative to paper chromatography, itoffers:

- higher separation power;- improved sensitivity;- shorter analysis times: some separations which

take several hours on paper can be carried out injust a few minutes, given the appropriate layer.

At the current state of the art, it can reasonably beassumed that thin-layer chromatography will largelyreplace paper chromatography for the separation oflipophilic substances, but such a replacement seemspremature for the separation of hydrophilic substances.

High-pressure liquid chromatography (HPLC)In this technique a high-pressure mobile phase ispumped through a stationary phase made of pressure-packed microparticle material covered, in some cases,with a partition liquid.The advantages offered by this technique, when it canbe applied as an alternative to those previouslydescribed, are as considerable as they are obvious:- much faster separation and very brief analysis time

(10 - 30 minutes);- high versatility and the possibility to separate heat-

sensitive and explosive substances, since theanalysis can be conducted at room temperature;

- requires very small sample volumes given the highsensitivity achieved in UV (nanograms) and fluores-cence or with electrochemical detectors(picograms);

- possibility to quickly separate even complex mix-tures with precision, accuracy and repeatability andwith minimum dexterity skills given the ease of theprocess;

- low cost per analysis;- satisfactory qualitative and quantitative results;- chromatograms comparable with those obtained

through conventional gravity-induced mobile phaseflow chromatography or through gas chromatogra-phy, to which this technique is rather similar.

Chromatography

35

Adsorbents

Besides the widely used silica gel, other products with particular characteristics are also available and offer aseries of valid alternatives for resolving numerous separation problems.

36

Chromatography

Product Applications Characteristics Size Code

Activated carbon General Powder 250 g 434455 1000 g 434454Aluminum oxide, acidic Dicarboxylic amino acids, Brockmann 250 g 417185 peptides, etc. 1000 g 417182Aluminum oxide, basic Polar compounds Brockmann 100 g 417214 1000 g 417217Aluminum oxide, neutral Ketosteroids, glucoside ketals, Brockmann 250 g 417245 lactones, esters 1000 g 417241 2500 g 417248Calcium hydroxide General Powder 250 g 433905Cellulose General Powder 250 g 436061Clarcel FLO M Solid-liquid separation Cake density: 170-215 g/l 1000 g P8770017 Permeability: 1.4 - 3.8 darcies 5000 g P8770027Diatomaceous earth compound General Powder 250 g 449895 1000 g 449897Florisil Column separation of organic 60-100 mesh 100 g 452331 substances 500 g 452333 Pesticide analysis 60-100 mesh 100 g 452271 500 g 452273Florisil Column separation of organic 100-200 mesh 100 g 452351 substances 500 g 452353Magnesium oxide General Powder 1000 g 459617Polyamide TLC Powder 250 g 470021Purified sand Flash chromatography 40-100 mesh 1000 g 477153Silica gel TLC Stahl 250 g 453345 1000 g 453347 Flash chromatography 40-63 m 100 g 453351 500 g 453352 1000 g 453353 5000 g 453355 General with wide versatility 60-200 m 500 g 453336 1000 g 453337 5000 g 453332Silica gel 100 Å General with wide versatility 5 m 1000 g P205RS17 10 m 1000 g P206RS17 16 m 1000 g P207RS17 30 m 1000 g P208RS17 50 m 1000 g P209RS17Silica gel 300 Å General with wide versatility 5 m 1000 g P210RS17 10 m 1000 g P211RS17 15 m 1000 g P212RS17 20 m 1000 g P213RS17 40 m 1000 g P214RS17Silica gel 60 Å General with wide versatility 6-35 m 1000 g P2010017 5000 g P2010027 25 kg P2010044 40-63 m 1000 g P2050017 5000 g P2050044 25 kg P2050027 20-45 m 1000 g P2200017 5000 g P2200027 25 kg P2200044 35-70 m 1000 g P2000017 2000 g P2000026 5000 g P2000027 25 kg P2000044 70-200 m 1000 g P2100017 2000 g P2100026 5000 g P2100027 25 kg P2100044Silica gel 70 Å General with wide versatility 5 m 1000 g P200RS17 10 m 1000 g P201RS17 15 m 1000 g P202RS17 20 m 1000 g P203RS17 40 m 1000 g P204RS17Silica gel 1000 Å General with wide versatility 5 m 1000 g P215RS17 10 m 1000 g P216RS17 15 m 1000 g P217RS17 20 m 1000 g P218RS17 40 m 1000 g P219RS17

Clarcel FLO M is an effective filtration product obtained from expanded raw perlite. It represents an importantalternative to Celite 545, the composition of which causes the user to be exposed to crystalline silica, classified asa carcinogen by the International Agency for Research on Cancer (IARC).Its particularly high porosity and low compressibility make this product suitable for solid-liquid separations, withretention properties up to microscopic dimensions. It also has the following advantages:

- Improved safety for the users (respirable fraction of the crystalline silica concentration < 1%);

- Insoluble in organic acids and minerals at all temperatures (except hydrofluoric acid);

- Effective even with highly viscous liquids;

- Suitable for a wide variety of filtration conditions, even under vacuum or with high flow rates;

- It gives no odor or color to the separates.

TLC plates

Carlo Erba Reagenti offers a wide range of TLC plates with supports in glass, polyester and aluminum, available invarious formats to meet all the users's needs.

Chromatography

37

Type Thickness Dimensions Quantity Code (mm) (cm) per box

Analysis plates Polyester support

Alumina 60A F254 0.2 5 x 20 50 PCCM331325 0.2 20 x 20 25 PCCM331254 Alumina 60A 0.2 20 x 20 50 PCCM330254 Silica gel 60 F254 0.25 20 x 20 25 PCCM321354 0.25 5 x 20 50 PCCM321321 Silica gel 60 0.25 20 x 20 25 PCCM320354 0.25 5 x 20 50 PCCM320325 Aluminum support

Silica RP18 F254 0.2 20 x 20 25 PCCM251554 0.2 5 x 20 50 PCCM251525 Silica gel 60 F254 0.2 20 x 20 25 PCCM221254 0.2 5 x 20 50 PCCM221225 Silica gel 60 0.2 20 x 20 25 PCCM220254 Silica gel 60 with indicator 0.2 4 x 8 50 PCCM221205 Alumina 60A F254 20 x 20 25 PCCM231254 Glass support

Silica RP18 F254 1 20 x 20 15 PCCM151653 0.25 20 x 20 25 PCCM151351 0.25 10 x 10 25 PCCM151334 Alumina 60A F254 0.25 20 x 20 25 PCCM131354 Alumina 60A 0.25 20 x 20 25 PCCM130354 0.25 5 x 20 100 PCCM130327 Silica gel 60 F254 0.25 20 x 20 25 PCCM121354 0.25 10 x 20 50 PCCM121345 0.25 10 x 10 25 PCCM121335 0.25 5 x 20 100 PCCM121327 0.25 5 x10 50 PCCM121315 Silica gel 60 0.25 20 x 20 25 PCCM120354 Silica gel 60 0.25 10 x 20 50 PCCM120345 Silica gel 60 0.25 5 x 20 100 PCCM120327 Silica gel 60 0.25 5 x10 50 PCCM120315Preparative plates Glass support

Alumina 60A F254 1 20 x 20 15 PCCM131653 Silica gel 60 2 20 x 20 12 PCCM120758 1 20 x 20 12 PCCM120653 0.5 20 x 20 25 PCCM120459 Silica gel 60 F254 0.2 20 x 20 25 PCCM121758 variable 20 x 20 25 PCCM121854 1 20 x 20 25 PCCM121653 0.5 20 x 20 25 PCCM121459HPTLC plates Glass support

Silica 60/10 F254 0.2 10 x 10 25 PCCM111234 0.5 10 x 10 25 PCCM111231Chiral plates Chiral F254 20 x 20 25 PCCM171354

TLC plate visualization systemsTLC visualization is greatly simplified when plates with fluorescence indicators can be used. When placed under aUV lamp at 254 and 366nm, the substances become visible as dark spots on a fluorescent background.Alternatively, general reagents can be used, such as iodine, sulfuric acid, acid/nitric acid, sulfuric acid/potassiumdichromate which allow, after appropriate treatment, visualization of the separated products. Some classes ofcompounds may in fact be visualized by means of specific reactions, using appropriate chromogenic solutionssprayed on the TLC plates.

For information on accessories, instruments, columns and HPLC/GC syringes, see our "Labware" catalogue.

ApplicationsSpecific reagents for the preparation of chromogenic solutions.

Solvents

From a qualitative point of view, HPLC solvents have had to adapt to the increasingly specific needs of bothinstruments and methods, especially in terms of active impurities which could compromise the correctness andselectivity of the result by interacting with the analytical complex.Consequently, our HPLC solvents are accurately and specifically produced by means of forced distillation / filtra-tion, and then controlled and packaged to adequately meet the needs of this analytical technique.

Solvents for HPLC - LC/MSLiquid chromatography coupled with mass spectrometry is a recently developed technique which is suitable forthe analysis of fairly polar, non-volatile and thermally stable compounds. It allows the separation and characteri-zation of many more compounds than GC-MS chromatography and also provides information on the molecularweight and structure of the HPLC peaks. The significant advantages of this combined technique has lead to itswidespread use in many analytical fields, particularly in the pharmaceutical, environmental and biotechnologicalsectors.38

Chromatography

Compound classes Chromogenic solutions

Steroids and sterols, phenols, lipids and sulfides(blue spots on a yellow background)

Phosphomolybdic acid

Carbohydrates (various shades of blue) Anisic aldehyde (in sulfuric acid, acetic acid and ethanol)

Reducing sugars (various colors) Aniline phthalate (aniline and italic acid in n-BuOH /H2O)

Vitamins A, D, E and terpenes Antimony trichloride, saturated solution in chloroform

Steroids, steroidic glucosides, aliphatic lipids, vitamin A, etc.(various colors)

Antimony trichloride, saturated solution in chloroform

Halides Silver nitrate / ammonia – acidic fluoresceinA) 1% Ammoniacal AgN03B) 0.1% Fluorescein in ethanol

Primary amines derived from indole Dimethylaminobenzaldehyde (hydroalcoholic solution)

Aldehydes and ketones (varying from yellow to red) 2,4-Dinitrophenylhydrazine (0.5% in HCI2N)

Phenols (various colors) Ferric chloride (1% in water)

Unsaturated compounds (yellow spots on a pink background) Fluorescein-bromine (0.04% in H2O + Br2 vapors)

Inorganic cations (various colors) 8-Oxyquinoline-Ammonia (NH3 vapors + 0.5 %

oxyquinoline in ethanol - water 60/40)

Barbiturics (gray spots on a colorless background), the same reactionalso occurs for many amines

Mercurous nitrate

Amino acids, aminophosphatides, amino sugars (blue) Ninhydrin (0.2 % in 5% aqueous acetic acid solution)

Halides, except fluorides, dicarboxylic acids(yellow spots on a purple background)

Bromocresol purple (0.1% in ethanol and ammonia)

Alkaloids, organic bases in general (orange) Dragendorff reagentA) 1.7% basic bismuth nitrate in 20% acetic acidB) 40g of potassium iodide in 100ml of H2O

Carboxylic acids (yellow spots on a green background) Bromocresol green 0.3% in methanol / H2O ratio 8:2 -

alkalinized

Product Package Code

Anisic aldehyde 100 ml 415312Antimony trichloride 100 ml 422834Basic bismuth nitrate 100 g 428294Bisublimed iodine 250 g 455955Bromocresol purple 5 g 470038Bromocresol purple 0.4% 250 ml 470045p-Dimethylaminobenzaldehyde 100 g 4446042,4-Dinitrofluorobenzene 10 g 445701Fluorescein acid 50 g 452083Fluorescein sodium 50 g 452113Hydrindantin 5 g 455291

Product Package Code

Mercurous nitrate 100 g 461154Ninhydrin 25 g 464922Nitric acid 69.5 % 1000 ml 4080718-Oxyquinoline 50 g 467353Perchloric acid 65% 1000 ml 409111Phosphomolybdic acid 50 g 405913Phthalic acid 250 g 406205Potassium dichromate 500 g 470336Potassium iodide 250 g 472735Silver nitrate 25 g 423952Sulfuric acid 96% 1000 ml 410301

LC-MS grade acetonitrile and methanol are available, characterized by:

• Guaranteed specifications of a high-performanceLC solvent (high titer, low acidity, alkalinity andresidue, ideal fluorescence, absorbance/transmit-tance and gradient test);

• Low metal content, in the order of ppb, in orderto prevent interactions with ionized species inthe mass analyzer;

• Low particulate;

• LC-MS suitability: no signal is greater than the molecular peak of reserpine (609 amu) at the concentrationof 100 ppb, in a range from 50 to 2000 amu.

Solvents for HPLC - Ultragradient gradeThe solvents of this product line guarantee excellent short-wavelength performance and limited drift, whichmakes them ideal for gradient and trace analysis.

Chromatography

39

Product Size Code

Acetonitrile RS for HPLC - LC/MS 1000 ml 412341 2500 ml 412342Methanol RS for HPLC - LC/MS 1000 ml 414831 2500 ml 414832

Acetonitrile Methanol

Application HPLC LC-MS HPLC LC-MS

Code 412342 414832

Titer (GC) >= 99,9 % >= 99,9 %

Water <= 0,01 % <= 0,02 %

Non-volatile residue <= 2 ppm <= 2 ppm

Acidity <= 0,0005 meq/g <= 0,0003 meq/g

Basicity <= 0,0002 meq/g <= 0,00006 meq/g

UV transmittance (1 cm - Ref: water) at 195 nm >= 80 % at 200 nm >= 93 % at 210 nm >= 30 % at 220 nm >= 98 % at 225 nm >= 65 % starting from 230 nm >= 98.5 % at 235 nm >= 85 % at 250 nm >= 95 % starting from 260 nm >= 98 % UV cut off <= 190 nm

Fluorescence (quinine) at 254 nm <= 1 ppb <= 1 ppb at 365 nm <= 0.5 ppb <= 1 ppb

HPLC capabilities Binary gradient test H20/CH3CN from 5 Binary gradient test H20/CH30H from 5 to 90% in acetonitrile in 16 minutes at to 90% in methanol in 16 minutes at 1.8 ml/min 1.8 ml/min

Gradient test conforms conforms at 210 nm <= 1 mA.U. at 235 nm <= 2 mA.U. at 254 nm <= 0.5 mA.U. <= 1 mA.U.

LC/MS capabilities TIC 50-2000 m/z ESI(+) Sensitive impurities (Ref: reserpine) <=100 ppb <= 100 ppb

Metalli Aluminum (Al) <= 50 ppb <= 50 ppb Calcium (Ca) <= 50 ppb <= 50 ppb Iron (Fe) <= 50 ppb <= 50 ppb Potassium (K) <= 50 ppb <= 50 ppb Magnesium (Mg) <= 50 ppb <= 50 ppb Sodium (Na) <= 50 ppb <= 50 ppb

Product Size Code

Acetonitrile Gold ml 1000 412371 ml 2500 412372 ml 4000 412374 ml 5000 412375Methanol Gold ml 1000 412721 ml 2500 412722 ml 4000 412724 ml 5000 412725

Product Size Code

Acetonitrile Ultragradient Grade mL 1000 P00637U16 mL 2500 P00637U21

Solvents for HPLC - Gradient gradeThese solvents are high-purity products for very sophisticated uses, with guaranteed fluorescence and transmit-tance limits.

Mobile phases for HPLCClients may request quotes on and order eluent mixtures for HPLC gradient analysis, which provides the followingadvantages: time savings, improved certainty and guaranteed quality.Just send your request to the e-mail address chemicals@carloerbareagenti.com, specifying the solvents of inter-est, the ratio between their concentrations and the volume requested.

Solvents for HPLC - Isocratic gradeThis is a line of solvents which, due to their high purity and strictly controlled chemical-physical parameters, ade-quately meet the needs of modern analytical HPLC.

40

Chromatography

Product Size Code

Acetonitrile Plus ml 1000 412391 ml 2500 412392Ethanol Plus ml 1000 412701 ml 2500 412702Isopropanol Plus ml 1000 412711 ml 2500 412712Methanol Plus ml 1000 412381 ml 2500 412383Water Plus ml 1000 412141 ml 2500 412142

Product Size Code

Acetonitrile Gradient ml 1000 P00637G16 ml 2500 P00637G21 ml 5000 P00637G31Methanol Gradient ml 1000 P09337G16 ml 2500 P09337G21

Product Size Code

Acetone ml 2500 412502Acetonitrile ml 1000 412411 ml 2500 412412Anhydrous Ethanol ml 2500 412522Isopropanol ml 1000 412421Cyclohexane ml 1000 412431Chloroform stab. in Ethanol ml 1000 412652 ml 2500 412653Dichloromethane stab. in Amylene ml 1000 412621 ml 2500 412622Ethyl Acetate ml 2500 412612n-Heptane ml 2500 412592n-Hexane ml 1000 412601 ml 2500 412602Isooctane ml 1000 412441Methanol ml 1000 412533 ml 2500 412532n-Propanol ml 2500 412542Tetrahydrofuran ml 1000 412451 ml 2500 412452Toluene ml 2500 412642

Product Size Code1,2-Dichloroethane ml 1000 P0283716 ml 2500 P02837211,4-Dioxane ml 1000 P03637161,4-Dioxane stab. in BHT ml 1000 P03637S161-Chlorobutane ml 1000 P02237162-Methyltetrahydrofuran ml 100 P9963716 ml 2500 P9963721Acetone ml 1000 P0053716 ml 2500 P0053721Acetonitrile ml 1000 P0063716 ml 2500 P0063721Chloroform stab. in Amylene ml 1000 P02437A16 ml 2500 P02437A21Chloroform stab. in Ethanol ml 1000 P02437E16 ml 2500 P02437E21Cyclohexane ml 1000 P0253716 ml 2500 P0253721Dichloromethane stab. in Amylene ml 1000 P02937A16 ml 2500 P02937A21Dichloromethane stab. in Ethanol ml 1000 P02937E16 ml 2500 P02937E21Diethyl Ether ml 1000 P0443716 ml 2500 P0443721Diisopropyl Ether ml 2500 P0433721Ethyl Acetate ml 1000 P0023716 ml 2500 P0023721Hexane 99% ml 1000 P052373016 ml 2500 P052373021Isohexane ml 1000 P6263716 ml 2500 P6263721Isooctane ml 1000 P0633716 ml 2500 P0633721Isopropanol ml 1000 P0953716 ml 2500 P0953721Methanol ml 1000 P0933716 ml 2500 P0933721 ml 5000 P0933729Methyl tert-Butyl Ether ml 1000 P0923716 ml 2500 P0923721n-Heptane ml 1000 P0503716 ml 2500 P0503721n-Hexane ml 1000 P0523716 ml 2500 P0523721Tetrahydrofuran ml 1000 P0703716 ml 2500 P0703721Tetrahydrofuran, stabilized ml 1000 P07037S16 ml 2500 P07037S21Toluene ml 1000 P0713716 ml 2500 P0713721Water ml 1000 P0153716 ml 2500 P0153721

Solvents for preparative HPLCThese products are able to guarantee contamination-free separations and purifications.

Derivatizers

Derivatizers are substances that allow thechemical modification of a molecule inorder to alter its properties and make itadaptable to a specific analytical proce-dure. Originally GLC benefited most fromthe advantages of derivatization, but sub-sequently the technique's applicationsextended to other types of analysis suchas mass spectrometry, magnetic nuclearresonance, UV and visible spectrophotome-try, fluorimetry, electroanalysis and radio-analysis.A selection of the most frequently usedderivatizers are listed in the table on theright.

Reagents for pre- and post-column modification in HPLC

Both pre- and post-column reactions are used in HPLC: on-lineand off-line. The pre-column reaction allows optimization ofselectivity and sensitivity, improves stability, resolution and peaksymmetry, and allows shortening or lengthening of solute reten-tion times.The post-column reaction combined with the use of a fluores-cent or coloring reagent increase the detector's efficiency. Theavailability of a wide range of products which can react on thefunctional group greatly facilitates spectrophotometric or fluori-metric separation and detection of products that would other-wise be difficult to analyze.

Reagents for ion pair chromatography

This type of chromatography can be used to solve commonanalytical problems related to ionic or polarized products.The following reagents are additives for the mobile phasethat allow the separation in reversed-phase HPLC of ionicor highly polar substances (counter-ion tetraalkylammoni-um for anionic electrolytes, alkyl or aryl sulfonate forcationic electrolytes).

Chromatography

41

Product Size Code

Chloroform stab. in Ethanol ml 2500 438641Dichloromethane stab. in Amylene ml 2500 463281Ethyl Acetate ml 2500 448211Isopropanol ml 2500 415112Methyl tert-Butyl Ether ml 2500 432022Toluene ml 2500 488531

Product Size Code

Acetonitrile ml 2500 P00637P21Ethyl acetate ml 2500 P00237P21N-Hexane ml 2500 P05237P21Hexane Mixture of Isomers ml 2500 P0520037P21Tetrahydrofuran ml 2500 P07037P21

Product Size Code

Benzenesulfonyl chloride ml 10 4262314-Dimethylaminopyridine g 25 444512Dimethyldichlorosilane ml 100 444771N,N,-Dimethylformamide dimethyl acetal ml 10 444901Heptafluorobutyric acid ml 10 405451Hexamethyldisilane ml 1 447023 ml 25 447024Hexamethyldisilazane ml 1 446733 ml 25 446731Hexamethyldisiloxane ml 1 446743Methyl isothiocyanate g 100 462531Methyltrichlorosilane ml 250 462964 ml 2500 462968N-Acetylimidazole g 25 400713N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) g 1 461832N-Trimethylsilylacetamide g 25 489951N-Trimethylsilylimidazole ml 1 489963N,0-Bis(trimethylsilyl) acetamide (BSA) ml 1 489933 ml 25 489934N,0-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) ml 1 489563 ml 25 489561Pentafluoropropionic anhydride ml 1 x 10 422082Tetracyanoethylene g 10 487091Trifluoroacetic anhydride ml 25 422221 ml 100 422222Trimethylchlorosilane ml 1 489923 ml 100 489921 ml 1000 489926Vegetable oil characterization: Silylating reagent n. 1 ml 1 X 10 478043

Product Size Code

P-Bromophenacyl bromide g 10 4303612',7'-Dichlorofluorescein g 10 4425413,5-Dinitrobenzoyl chloride g 25 4453612,4-Dinitrofluorobenzene g 10 445701Fluorescein sodium g 5 452113 g 1000 452117Fluorescein acid g 50 452083 g 500 452087Hydrindantin g 5 4552912-Mercaptoethanol ml 10 460691Methyl isothiocyanate g 100 462531Ninhydrin g 5 464928 g 25 464922o-Phthalaldehyde (OPA) g 10 452751

Product Size Code

Cetyltrimethylammonium bromide 50 g 489833 500 g 489831Dodecylbenzenesulfonic sodium salt 10 g 4053511-Heptanesulfonic acid sodium salt 25 g 4058511-Hexanesulfonic acid sodium salt 25 g 4056211-Octanesulfonic acid sodium salt 25 g 4058611-Pentanesulfonic acid sodium salt 25 g 405841Tetramethylammonium acid sulfate 250 g 487101Tetramethylammonium hydroxide 10% 100 ml 487491p-toluenesulfonic acid sodium salt 100 g 411504

Standards for ion chromatography

Our standard solutions for ion chromatography are obtained by dissolution of a high-purity salt (+99.9%) inwater. They are characterized by:

• Concentrations equal to 1000 ppm;

• Guaranteed titer with a tolerance of 0.2% at the 95% confidence level;

• Raw materials selected and verified against N.I.S.T. Standard Reference Materials;

• Available in 50,100,250 and 500ml HDPE bottles;

• Certificate of analysis with references on the analytical method, the N.I.S.T. Standard Reference Materialsand the confidence interval;

• Shelf life, for the unopened product package, of 2 years.

For instrument calibration, the following multi-ion standard solutions are available for ion chromatography, com-plete with certificate of analysis with references on the analytical method, the N.I.S.T. Standard ReferenceMaterials and the confidence interval.

Carlo Erba Reagenti offers its clients the possibility of requesting quotes on and ordering custom-made multi-ionsolutions.Just send your request to the e-mail address chemicals@carloerbareagenti.com, specifying the ions of interest,their respective concentrations and the volume requested.

Concentrated mobile phases for ion chromatographyThe following eluents are filtered at 0.2µm and prepared from ultra-pure salts and 18-megaohm deionized water.These are concentrated solutions that should be diluted by a factor of 100.The shelf life for the unopened product package is 2 years.

42

Chromatography

Code

Ion Matrix Concentration 50 ml 100 ml 250 ml 500 ml

Ammonium (NH4+) water 1000 ppm 503310 503311 503312 503313

Bromates (BrO3-) water 1000 ppm 503170 503171 503172 503173

Bromides (Br-) water 1000 ppm 503210 503211 503212 503213Calcium (Ca2+) water 1000 ppm 503220 503221 503222 503223Cyanides (CN-) water and sodium hydroxide 1000 ppm - 503358 - -Chlorates (ClO3

-) water 1000 ppm 503180 503181 503182 503183Chlorites (ClO2

-) water 1000 ppm 503190 503191 503192 503193Chlorides (Cl-) water 1000 ppm 503230 503231 503232 503233Chromates (CrVIO4

2-) water 1000 ppm 503240 503241 503242 503243Fluorides (F-) water 1000 ppm 503250 503251 503252 503253Phosphates (PO4

3-) water 1000 ppm 503340 503341 503342 503343Iodides (I-) water 1000 ppm 503260 503261 503262 503263Lithium (Li+) water 1000 ppm 503280 503281 503282 503283Magnesium (Mg2+) water 1000 ppm 503290 503291 503292 503293Nitrites (NO2

-) water 1000 ppm 503320 503321 503322 503323Nitrates (NO3

-) water 1000 ppm 503330 503331 503332 503333Potassium (K+) water 1000 ppm 503270 503271 503272 503273Sodium (Na+) water 1000 ppm 503300 503301 503302 503303Sulfates (SO4

2-) water 1000 ppm 503350 503351 503352 503353

Code

Ion Matrix Concentration 100 ml

8 anions: Fluorides (F-), Chlorides (Cl-), Bromides (Br-), Nitrites (NO2-),

Nitrates (NO3-), Phosphates (PO4

3-), Sulfates (SO42-), Acetates (CH3COO-) acqua 1000 ppm per ciascun ione 504517

Description Matrix Size Code

0.18 M Sodium carbonate / 0.17 M Sodium bicarbonate water 100 ml 5045300.22 M Sodium carbonate / 0.28 M Sodium bicarbonate water 100 ml 5045310.35 M Sodium carbonate / 0.1 M Sodium bicarbonate water 100 ml 5045320.5 M Sodium carbonate water 100 ml 5045330.17 M Sodium bicarbonate water 100 ml 504534