分散液相微萃取-连续光源-石墨炉原子吸收光谱法测定水样中痕量铬(Ⅵ)

Determination of trace chromium (Ⅵ) by dispersive liquid-liquid microextraction combined with continuum source-graphite furnace atomic absorption spectrometry

采用分散液相微萃取-连续光源石墨炉原子吸收光谱法,以吡咯烷基二硫代氨基甲酸铵（APDC）为螯合剂,CCl4为萃取溶剂,乙醇为分散剂测定环境水样中痕量Cr（VI）,并考察了pH、萃取时间、温度和盐度等影响因素。结果表明,DLLME萃取5 mL水样的最佳条件为：pH 2.0,温度为35℃,螯合剂0.012 g/L,萃取溶剂30μL,分散剂0.5 mL。在此条件下,水样中铬（VI）的检出限为0.005μg/L,线性范围为0.05-2.00μg/L,对0.20μg/L,1.00μg/L Cr（VI）标准液分别测定10次的相对标准偏差为0.3%和2.4%。

A method of dispersive liquid - liquid microextraction prior continuum source-graphite furnace atomic absorption spectrometry was used to determine trace chromium （Ⅵ） in environmental samples with ammonium pyrrolidine dithiocarbamate （APDC） as chelating agents, CCl4 as an extraction solvent and ethanol as a dispersant, and the factors （ pH, extraction time, results showed that the optimum conditions for the temperature was 35 ℃ and the volumes of chelating temperature and salinity, etc. ） have been discussed. The extraction of 5 mL of samples was as follows ： pH were 2.0, ,extraction agent and dispersants was 0. 012 g/L, 30 μL and 0.5 mL respectively. Under the optimum conditions, The detection limit of chromium（Ⅵ） in water samples was 0. 005 Ixg/L and the linear range was 0. 05 - 2.00 μg/L. The relative standard deviation were 0. 3% and 2. 4% when the concentrations of 0. 20 μg/L and 1.00 μg/L Cr （Ⅵ） standard solutions were measured 10 times.