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In the name of God

Solid phase extraction & cold vapor atomic absorption spectrometry

December 2014

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Introduction & background

Methods

Application

Outline

Conclusion

IntroductionSolid phase extraction is the very popular technique currently available for rapid and selective sample preparation. The versatility of SPE allows use of this technique for many purposes, such as purification, trace enrichment, desalting, and class fractionation and etc.

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SPE procedure

The formats in SPE

•Free disks

•Cartridge

•96-well plates

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Cartridges

The SPE cartridge is a small plastic or glass open-ended container filled with adsorptive particles of various types and adsorption characteristics.

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DiscsDiscs consist of a 0.5 mm thick membrane where the adsorbent is immobilized in a web of microfibrils.The sorbent (on polymer or silica) is embedded in a web of PTFE or glass fibre.

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96-well plates

The new format of SPE is 96-Well SPE Plates.Parallel sample processing allows 96 samples to be extracted in approximately one hour or less.

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Advantage for SPE

Solid phase extraction has been widely used in the separation and preconcentration of various species. There are many advantages to this technique, such as simplicity, reliability, reduction in analysis time, reduction or elimination of the use of organic solvents and a high potential for automation.

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Atomic absorption spectrometry

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CV-AAS

Paper1: A new method for preconcentration and determination of mercury in fish, shellfish and saliva by CV-AAS

1. separation and preconcentration of mercury

2. measurement of mercury was performed in CV-AAS

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Sample preparations for the determination of mercury in human saliva

1. Samples were collected from healthy volunteers aged 20-25 years. 2. 2 ml of sample was transferred to teflon cup of acid digestion bomb

3. HN(65% w/v, 4 ml) and (30% v/v, 1ml) were added.

4. The digestion bomb flask was placed in an oven at c for 6 h.5. Cooling and adjusting the pH with a NaOH solution

6. The digest was transferred to a 100 ml volumetric flask containing 20 ml of buffer solution

7. Finally, the flask was filled to volume with ultrapure water.

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Sample preparations for the determination of mercury in fish, shellfish:

1. 0.1 g of sample was weighed

2. Transferred to teflon cups in order to microwave the acid digestion bombs.

3. 2.0 ml of 65% (w/v) HN and 1.0 ml of ultrapure water were added.

4. The system subjected to microwave radiation for 60 s at a power of 100 w.

5. Cooling and adjusting the pH with a NaOH solution

6. The digest was transferred to a 100 ml flask containing 20 ml of buffer solution.

7. Finally, the flask was filled to volume with ultrapure water.

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Optimization of conditions for the preconcentration

A 1.0 µg Hg (II) solution was used in the optimization of variables. The extraction of the element by XAD-BTAC was calculated using the following equation: E = (CV/) x 100, where C is the concentration of mercury in the eluent, V is the volume of the eluent, is the initial concentration of mercury in the solution passed through the minicolumn, and is the volume of the mercury solution that was passed through the minicolumn.

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Effect of pHpH plays an important role in the ligand–metal interaction

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Effect of concentration of eluent

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1.75 mol concentration of HCl was chosen

Effect of flow rate of eluent

• The effect of the flow of eluent was examined in the range from 1.0 to 8.1 mL

• Employing flow values between 5.5 and 8.1 mL , no significant variation on response was observed.

the value of 6.6 ml for the flow of the

eluent was chosen.

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Sample flow rate

●The sorption of Hg (II) on functionalized resin was studied at flow rates varying from 1.0 to 10.1 ml

● The best results were obtained when the flow rates were from 1.0 to 6.6 mL.

● A flow of 5.5 ml was established to provide a high sampling rate without compromising retention of hg (II).

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Results for determination of mercury in certified reference material and saliva samples.

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Results for determination of mercury in seafood samples using the proposed procedure.

Characteristics of methods using solid phase extraction for preconcentration of mercury

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LOD: limit of detection; EF: enrichment factor; PDCA: 2,6-pyridine dicarboxylic acid; AATP: 2-aminoacetylthiophenol; 1,2-BAE: 1,2-bis(o-minophenylthio)ethane; PSDVB: polystyrene–divinylbenzene; ACPG: aminopropyl-controlled pore glass; PSTH: 1,5-bis(2 pyridyl)-3-sulphophenyl methylene thiocarbonohydrazyde; DPTH: 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide; TS: methylthiosalicylate; BG: Brilliant Green; MB: 2-mercaptobenzimidazole; TC: thiosemicarbazide

Amberlite XAD-4 (polystyrene–divinylbenzene) resin

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BTAC: 2-(2-benzothiazolylazo)-p-cresol

Molecular formula: OS

Systematic name: 2-[(E)-1,3-Benzothiazol-2-yldiazenyl]-4-methylphenol

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Conclusion• The proposed method for the determination of mercury proved to be

simple, efficient and easy to perform in the matrices analysed.

• The Amberlite XAD-4 functionalized with BTAC reagent, which was efficient for the complexation of Hg (II) allowing extraction/preconcentration with a high enrichment factor.

• The proposed procedure also presented analytical features (e.g., limit of detection, precision and accuracy) suitable for the determination of Hg(II) in both saliva samples and in fish and shellfish.

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SPE of ultra traces mercury (II) using octadecyl silica membrane disks modified by 1,3-bis(2-ethoxyphenyl)triazene (EPT) ligand and determination by CV-AAS

• pH=3.5

• Amount of ligand=7.5 mg

• Eluent= use 1.5 M perchloric acid solution

• Flow rate= 3 mL for the eluent and 50 mL for the sample

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Chemical structure of 1,3-di(2-ethoxyphenyl) triazene (EPT).

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Determination of Hg(ǁ) ions in 500 ml of real samples after applying recommended procedure.

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Comparing the performance of this method with other methods for determination of ions.

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SPE of Cd on 2-mercaptobenzothiazole loaded on sulfur powder in the medium of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and CVG-AAS determination

• pH=8.5 using either 0.1 mol HN & NaOH solutions

• parameters using either 2.5 ml of 2 mol of HCl

• flow rate a flow rate of 8 mL was selected for the

eluent and 12 mL for the sample

• sample volume the maximum sample volume is 200mL 31

Chemical structure of ligands:

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1-butyl-3-methylimidazolium hexafluorophosphate

2-mercaptobenzothiazole

Determination of cadmium in water samples

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Determination of cadmium in fish samples

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Comparison of papers

sample element sample flow rate

adsorbent

pH

paper1 Water & fish

mercury 6 ml Agar modified

2.5

paper2 Water & fish

mercury 4 ml Dowex

OptiporeV-493

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paper3 Water & fish

mercury 16 ml sulfur 8.5

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Comparison of papers

ligand eluent solution DL

Linear rang

paper12-mercaptobenzimidazole

HCl 0.2ng

0.04-2.4ng

paper2S. aureus HCl __ __

paper3 N-(2-chlorobenzoyl)-N-phenylthiourea

HCl __ __

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Structure of ligands

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N-(2-chlorobenzoyl)-N-phenylthiourea 2-mercaptobenzimidazole

Refrences:

• V. A. Lemos, L. O. dos Santos, 2014, Food Chemistry., 149, 203–207.

• M. K. Rofouei, A. Sabouri, A. Ahmadalinezhad, H. Ferdowsi, 2011, Journal of Hazardous Materials., 192, 1358–1363.

• N. Pourreza, K. Ghanemi, 2010, Journal of Hazardous Materials., 178, 566–571.

• N. Pourreza, H. Parham, A. R. Kiasat, K. Ghanemi, N. Abdollahi, 2009, Talanta., 78, 1293–1297.

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• N. Pourreza, K.Ghanemi, 2009, Journal of Hazardous Materials., 161, 982–987.

• M. Tuzen, I. Karaman, D. Citak, M. Soylak, 2009, Food and Chemical Toxicology., 47, 1648–1652.

• A. Żwir-Ferenc, M. Biziuk, 2006, Polish J. of Environ. Stud., 15, 677-690.

• www.mercury-instrumentsusa.com

• www.sigmaaldrich.com

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THANK YOU

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Any question?

No?!!!

Thank YOU!!!