GFAAS Determination of Lead in Popped Food with Cloud Point Extraction

Trace amount of Pb(Ⅱ) was separated and enriched from the sample solution buffered at pH 9 in the form of a coordination complex with 8-HQ by cloud point extraction using Triton X-100 as surfactant. An aliquot of the surfactant phase was diluted and made up to 2 mL with 0.1 mol·L-1 HNO3 solution and the lead content was determined by GFAAS. Factors influential to cloud point extraction, and interferences of co-existing ions were studied. Detection limit (3σ) of the method was found to be 0.85 pg. The proposed method was applied to the determination of lead in popped food samples, and values of recovery obtained by addition of standards to 5 different samples were in the range of 91.7%-101.7%.