浮动液滴固化分散液相微萃取-火焰原子吸收光谱法测定环境样品中的镉

摘要

A new method was established to determine trace cadmium in environmental samples by combining dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) with flame atomic absorption spectrometry (FAAS). The main parameters affecting the performance of DLLME-SFO, such as type and volume of extraction solvent,pH, concentration of chelating agent, extraction temperature and time, were investigated. It was found that, under the optimized experimental conditions, the method had a detection limit (3σ) of 0.14 μg/L, linear range of 2.0-50.0 μg/L, relative standard deviation (RSD) of 2. 5 /％ (c = 10.0 μg/L, n = 7), and enrichment factor of 18. The method was successfully applied to determine trace cadmium in the certified reference water sample (GBW(E) 080531) and various to-be-tested water samples. The analytical result for the certified reference water sample was in good agreement with the certified value, and the recoveries for the spiked water samples were in a range of 94 ％-103 ％.%建立了以十一醇为萃取剂,吡咯烷二硫代甲酸铵(APDC)为螯合剂的浮动液滴固化分散液相微萃取-火焰原子吸收光谱法(DLLME-SFO-FAAS)测定环境样品中痕量镉的分析方法;优化了分散剂、萃取剂的类型和体积,考察了溶液pH值、APDC浓度以及萃取温度和时间对萃取效率的影响.结果表明,该法检出限(3σ)为0.14μg/L,相对标准偏差RSD为2.5%(c=10.0 μg/L,n=7),线性范围为2.0～50.0 μg/L,富集倍数18.将其用于水中镉标准物质(GBW(E)080531)和实际环境水样中痕量镉的测定,测定值与标准值吻合良好,实际样品的加标回收率为94%～103%.