Salāmat-i kār-i Īrān (Apr 2006)
Purification and concentration of lead samples in biological monitoring of occupational exposures
Abstract
Background and Aims:Lead is an important environmental constituent widely used in industrialprocesses for production of synthetic materials and therefore can be released in the environmentcausing public exposure especially around the industrial residence area. For evaluation of humanexposure to trace toxic metal of Pb (II), environmental and biological monitoring are essentialprocesses, in which, preparation of such samples is one of the most time-consuming and errorproneaspects prior to analysis. The use of solid-phase extraction (SPE) has grown and is a fertiletechnique of sample preparation as it provides better results than those produced by liquid-liquidextraction (LLE). The aim of this study was to investigate factors influencing sample pretreatmentfor trace analysis of lead in biological samples for evaluation of occupational exposure.Method :To evaluate factors influencing quantitative analysis scheme of lead, solid phaseextraction using mini columns filled with XAD-4 resin was optimized with regard to sample pH,ligand concentration, loading flow rate, elution solvent, sample volume (up to 500 ml), elutionvolume, amount of resins, and sample matrix interferences.Results :Lead was retained on solid sorbent and eluted followed by simple determination ofanalytes by using flame atomic absorption spectrometery. Obtained recoveries of the metal ionwere more than 92%. The amount of the analyte detected after simultaneous pre-concentrationwas basically in agreement with the added amounts. The optimized procedure was also validatedwith three different pools of spiked urine samples and showed a good reproducibility over sixconsecutive days as well as six within-day experiments. The developed method promised to beapplicable for evaluation of other metal ions present in different environmental and occupationalsamples as suitable results were obtained for relative standard deviation (less than 10%).Conclusion:This optimized method can be considered to be successful in simplifying samplepreparation for trace residue analysis of Pb in different matrices for evaluation of occupationaland environmental exposures.
