Abstract

Ali Moghimi^1* and Mohamad Javad Poursharifi²

A novel and selective method for the fast determination of trace amounts of copper(II) and lead(II)ions in water samples has been developed. Sorbent particles consisting of nano and micro silica, and micron size octadecylsilica (ODS) were immobilized using sol–gel chemistry onto poly(dimethylsiloxane) (PDMS) microfluidic channels to serve as µ-chip solid phase extraction (SPE) devices. Extraction, preconcentration and purification of biological and chemical analytes were carried out using these. Micro and nano scale silica-immobilized µ-SPE were used for the extraction/purification of of trace copper and lead ions as their 4,4’-Dimethoxybenzil bisthiosemicarbazone (DBTS) chelates in environmental samples and lead determinations by atomic absorption spectrometry. The influences of pH of the model solutions, amounts of DBTS, eluent type and volume etc. were investigated. Also the effects of the matrix constituents of the samples were also examined. Separation of Copper and lead from real samples was achieved quantitatively. The procedure presented was checked with the analysis of standard reference materials (IAEA-336 Lichen and SRM 1515 Apple leaves). The preconcentration procedure was applied for the lead and copper contents of the natural water samples, some salts with satisfactory results (recoveries >96%, RSD <5%). LOD of the proposed method is 5ng per 1000mL.The method was applied to the extraction and recovery of copper in different water samples.

Preconcentration; Solid phase extraction; 4,4’-Dimethoxybenzil bisthiosemicarbazone (DBTS) ; Sol–gel; Poly(dimethylsiloxane) (PDMS)

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