Cloud point extraction for the determination of As(111) in water samples by electrothermal atomic absorption spectrometry

Cloud point extraction was applied as a preconcentration step for electrothermal atomic absorption spectrometry (ETAAS) determination of As(III) in aqueous solutions. After complexation with ammonium pyrrolidinedithiocarbamate, the analyte was quantitatively extracted to the surfactant-rich phase in the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X- 114) after centrifugation. 0.1 moL L-1 HNO3 in methanol was added to the surfactant-rich phase before ETAAS determination. The precision (R.S.D.) for 11 replicate determinations of 5.0 mu g L-1 of As(III) was 3.0%. The concentration factor, which is defined as the concentration ratio of the analyte in the final diluted surfactant-rich extract ready for ETAAS determination and in the initial solution, was 36 for As(III). The linear concentration range was from 0.1 to 20 mu g L-1. The developed method was applied to the determination of As(III) in lake water and river water. (c) 2005 Elsevier B.V. All rights reserved.