A new Na2SO4sahing-out extraction method has been developed for preconcentration trace amounts of copper as a prior step to its determination by UV-visible spectrophotometry, in which diethyldithiocarbamate(DDTC) was used as complexing agent,with chloroform as extraction solvent.Variables affecting salting-out extraction efficiency were investigated and optimized.Under the optimal conditions, the calibration curve was linear in the range of 0.002 μg/mL ～ 0.08 μg/mLof copper, detection limit was 0.11 ng/mL in original solution (3Sbc/m) and the relative standard deviation for seven replicate determination of 0.002 μg/mL copper was ± 1.9％.The proposed method has been applied for determination of copper in Honeysuckle, Radix Glycyrrhiza,Lycium samples with satisfactory results, the recovery were 103％, 102％ ,96％, RSD were 1.5％, 1.9％, 2.0％, respectively.%建立了以二乙基二硫代氨基甲酸钠(DDTC)为络合剂,硫酸钠-氯仿-水盐析萃取,紫外可见分光光度法测定痕量铜(Ⅱ)的新方法.研究了萃取的条件,共存离子的干扰.结果表明本法灵敏度高,选择性好,在最佳实验条件下,铜的线性范围为0.002～0.08μg/mL,0.002μg/mL铜标准液测定的RSD=1.9%(n=7),检出限为0.11ng/mL.应用于金银花、甘草、枸杞中铜的测定,回收率分别为103%、102%、96%,RSD分别为1.5%、1.9%、2.0%.
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