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  

Determination of Lead in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction with Dithizone

作　　者：肖珊美[1] 陈建荣[2] 沈玉勤[2] 

机构地区：[1]金华职业技术学院材料与化工学院,浙江金华321017 [2]浙江师范大学化学与生命科学学院,浙江金华321004

出　　处：《光谱学与光谱分析》2006年第5期955-958,共4页Spectroscopy and Spectral Analysis

基　　金：浙江省自然科学基金(202127);浙江省测试基金(04057)资助项目

摘　　要：基于表面活性剂的浊点现象,建立了以双硫腙为螯合剂、Triton X-114为表面活性剂的浊点萃取-石墨炉原子吸收光谱法测定痕量铅的新方法.研究了溶液pH值、试剂浓度、平衡温度和加热时间等实验条件对浊点萃取及测定灵敏度的影响.以4 000 r·min^-1离心15 min使分相,分相后的溶液在冰水浴中冷却至接近0℃,然后反转离心管弃去水相,用0.1 mol·L^-1HNO3^-甲醇溶液定容至0.5 mL,溶液以磷酸二氢铵及硝酸镁为基体改进剂由石墨炉原子吸收分光光度法进行测定.在pH 8.0和0.05%Triton X-114及20μmol·L^-1双硫腙存在下,富集10 mL样品溶液,铅的检出限为0.089μg·L,富集倍率为19.1,所得工作曲线回归方程为A=0.0261c（μg·L^-1）＋0.010 6,线性范围0.1～30μg·L^-1,相关系数r为0.998.方法用于环境水样中测定痕量铅的测定,获得满意结果.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 rprn. 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. 089μg · 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. 0261c（μg · L^-1）＋0. 0106. The proposed method has been applied to the determination of lead in water samples.

关 键 词：铅 浊点萃取 石墨炉原子吸收光谱法 双硫腙 

分 类 号：O657.3[理学—分析化学]