scholarly journals "ASSESSMENT OF THE TRACE LEVELS OF LEAD (II) USING SOLID PHASE EXTRACTION AND FLAME ATOMIC ABSORPTION SPECTROMETRY"

2006 ◽  
Vol 3 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Mohammad Saber Tehrani ◽  
Majid Mohammadhosseini

An efficient procedure for pre-concentration, separation and determination of the trace amounts of lead (II) ions in water samples has been established. The analyte is adsorbed on the surface of C18 silica membrane disk modified with APDC, quantitatively, while other interfering ions pass through the disk to drain. The sorbed Pb2+ ions are then stripped by appropriate eluting agents followed by monitoring of the eluates by flame atomic absorption spectrometry (FAAS). The effects of sample pH, amount of the modifier, stripping agent types, sample flow-rates, and potential interfering ions were also investigated. The described method involves a pre-concentration factor of about 200. The detection limit of the procedure is 0.93 ng.mL-1. The method was employed for isolation and determination of lead in different water samples.

2008 ◽  
Vol 73 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Renmin Gong ◽  
Demin Zhang ◽  
Keding Zhong ◽  
Min Feng ◽  
Xingyan Liu

This paper reports the preparation of a phosphorylated cotton chelator (PCC) by solid phase esterification of phosphoric acid (PA) onto defatted cotton fibres using urea as the catalyst. The synthesized PCC was employed for the preconcentration of copper from water samples prior to its determination by flame atomic absorption spectrometry (FAAS). The preconcentration of copper was studied under both batch and column techniques. The pH range for the quantitative preconcentration of copper was 4.0-7.0. The sorption time required for each sample was less than 30 min by the batch method. The copper sorption capacity of the PCC was found to be 15.3 mg/g at the optimum pH value. Elution with 1.0 mol dm-3 hydrochloric acid was found to be quantitative. Feasible flow rates of the copper solution for quantitative sorption onto the column packed with PCC were 0.5-4.0 ml min-1, whereas the optimum flow rate of the hydrochloric acid solution for desorption was less than 1.5 ml min-1. An 80-fold preconcentration factor could be achieved under the optimum column conditions. The tolerance limits for common metal ions on the preconcentration of copper and the number of times of column reuse were investigated. The proposed method was successfully applied for the preconcentration and determination of trace copper in natural and drinking water samples by FAAS.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Joyce Nunes Bianchin ◽  
Edmar Martendal ◽  
Eduardo Carasek

A new method for Ag determination in water samples using solid phase extraction (SPE) coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Ag preconcentration and extraction was the termite digestion product. Flow and chemical variables of the system were optimized through a multivariate procedure. The factors selected were adsorbent mass, buffer type and concentration, sample pH, and sample flow rate. The detection limit and precision were 3.4 μg L−1and 3.8% (n=6, 15 μg L−1), respectively. The enrichment factor and the linear working range were, respectively, 21 and 10–50 μg L−1. Results for recovery tests using different water samples were between 96 and 107%. The proposed methodology was applied with success for the determination of Ag in water used to wash clothes impregnated with silver nanoparticles, supplied by a factory located in Santa Catarina, Brazil.


2007 ◽  
Vol 72 (6) ◽  
pp. 585-590 ◽  
Author(s):  
Morteza Talebi ◽  
Homeyra Safigholi

Arapid, simple, and sensitive procedure based on modified solid phase extraction was developed for the pre-concentration and determination of trace amount of lead in water resources. Lead was reacted with ammonium pyrrolidinedithiocarbamate (APDC) to make a complex. The complex was then collected in a column packed with surfactant-coated alumina. The parameters affecting the collection efficiency and desorption rate of the lead complexes from the column were investigated and optimized. The collection efficiency of the lead complex on the adsorbent was excellent under the optimized conditions. The results obtained from the recovery test showed the capability and reliability of the method for the analysis of trace amounts of lead. The proposed pre-concentration procedure made it possible to apply conventional flame atomic absorption spectrometry (FAAS) for the sensitive determination of trace amounts of lead in water resources. .


2008 ◽  
Vol 91 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Tayebeh Shamspur ◽  
Ali Mostafavi ◽  
Iran Sheikhshoaie

Abstract A simple, selective, reliable, and sensitive method for the determination of trace amounts of Cu2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 102 g/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.


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