Determination of Lead in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction with Dithizone
XIAO Shan-mei1, 2, CHEN Jian-rong2*, SHEN Yu-qin2
1. Jinhua College of Profession and Technology, Jinhua 321017, China 2. College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China
Abstract：Cloud point extraction was used for the preconcentration of lead after the formation of a complex with dithizone in the presence of surfactant Triton X-114, and then the lead was determined by graphite furnace atomic absorption spectrometry. The conditions affecting the separation and detection process were optimized. Separation of the two phases was accomplished by centrifugation for 15 min at 4 000 rpm. Upon cooling in an ice-bath, the surfactant-rich phase became viscous. The aqueous phase could then be separated by inverting the tubes. Later, a solution of methanol containing 0.1 mol·L-1 of HNO3 was added to the surfactant-rich phase up to 0.5 mL. The samples were determined by graphite furnace atomic absorption spectrometry with NH4H2PO4 and Mg(NO3)2 as a chemical modifier. At pH 8.0, the preconcentration of only 10 mL sample in the presence of 0.05% Triton X-114 and 20 μmol·L-1 dithizone permitted the detection of 0.089 μg·L-1 lead. The enhancement factors were 19.1 times for lead. The calibration graph using the preconcentration system for lead was linear with a correlation coefficient of 0.998 from levels near the detection limits up to at least 30 μg·L-1. The regression equation was A=0.026 1c(μg·L-1)+0.010 6. The proposed method has been applied to the determination of lead in water samples.
Key words：Lead;Cloud point extraction;Graphite furnace atomic absorption spectrometry;Dithizone
肖珊美1，2,陈建荣2*,沈玉勤2 . 双硫腙浊点萃取-石墨炉原子吸收光谱法测定环境水样中痕量铅的研究[J]. 光谱学与光谱分析, 2006, 26(05): 955-958.
XIAO Shan-mei1, 2, CHEN Jian-rong2*, SHEN Yu-qin2 . Determination of Lead in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction with Dithizone. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2006, 26(05): 955-958.
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