Determination of Cadmium by Hydride Generation Atomic Fluorescence Spectrometry After Extraction with Ionic Liquid Two-aqueous Phase System
A procedure for the determination of cadmium by hydride generation atomic fluorescence spectrometry was developed after the cadmium-dithizone complex was extracted by using a two-aqueous phase system formed by ionic liquid 1-isopentyl-3-methylimidazolium bromide and K2HPO4.The cadmium-dithizone complex extracted in the ionic liquid-rich upper phase was acidified with hydrochloric acid and mixed with NaBH4 to facilitate the hydride generation process.The hydride was separated from the reaction mixture in a gas-liquid separator by purging with an argon flow,which was afterwards directed into the atomizer of the atomic fluorescence spectrometer for quantification.A thorough scrutiny has been made to optimize the experimental parameters,including the two-aqueous phase system itself.By using a sample volume of 1 mL,a linear calibration graph was obtained in the range of 0.25 -5.0 μg/L,along with a detection limit(3σ) of 0.07 μg/L and a precision of 3.4%(n = 9,2.0 μg/L Cd2 +).The procedure was demonstrated by analyzing cadmium content in a certified reference material(GBW08608) and real water samples.