Determination Of Trace Copper In Environmental Samples By Flame Atomic Absorption Spectrometry After On-Line Selective Preconcentration With Thioacetamide Modified Silica Gel Mini-Column

A selective and sensitive on-line preconcentration procedure was developed for the determination of trace levels of copped(II) by flame atomic absorption spectrometry(FAAS). A mini-column packed with a silica gel functionalized with thioacetamide was used for the on-line selective enrichment of copped(II) at pH 1.0. The copped(II) was eluted with 0.6 mol/L thiourea solution and determined by FAAS. Some important flow injection variables affecting preconcentration were optimized (sample flow rate was 8.0 mL/min, eluent flow rate was 5.0 mL/min and elution time was 60 s). Under the optimum conditions, linear calibration graphs over the concentration ranges of 2.0-100.0 mu g/L and 0.5-30.0 mu g/L; detection limits of 0.36 and 0.07 mu g/L; preconcentration factor of 80 and 170 were obtained for the preconcentration volumes of 10.0 and 50.0 mL of copped(II) solutions, respectively. The relative standard deviations for 9 replicate determinations of copped(II) were 3.5% and 2.0% at same conditions, respectively. The effect of the presence of various species commonly associated with environmental samples was also investigated. The method has been successfully applied to the selective determination of the trace Copper in standard reference materials (GBW07602, GBW08608 with satisfactory results.