Determination of Trace Amounts of Cr(III) in Water Samples by Flame Atomic Absorption Spectrometry

A fast and effective microextraction technique is proposed for the determination of trace amounts of Cr(III) in water samples, using ultrasound-assisted emulsification-microextraction (USAEME) followed by flame atomic absorption spectrometry (FAAS). In the proposed approach, sodium diethyldithiocarbamate trihydrate solution (NaDDTC.3H2O) was used as a chelating agent and chloroform was selected as extraction solvent. After determination of the most suitable solvent and extraction time, some effective parameters such as an extraction solvent volume, temperature, and pH were investigated and optimized. The optimized USAEME procedure used 100 μL of chloroform, 20 min of extraction with no ionic strength adjustment at 50 °C and 5 min of centrifugation at 4000 rpm. The method was applied to the analysis of tap, well, dam on industrial waste water samples and the Trace Metals in Drinking Water standards CRM-TMDV. The detection limit for Cr(III) was 0.079 μg L-1with an enrichment factor of 95, and the relative standard deviation was 2.8-1.1% (n=8, c=500 μg L-1). The proposed USAEME procedure has been demonstrated to be viable, simple, rapid and easy to use for the residue analysis separation of Cr(III).