双水相萃取-连续光源石墨炉原子吸收光谱法测定水样中的痕量锑

Determination of Trace Antimony in Water Samples by Aqueous Two-Phase Extraction-Continuous Light Source Graphite Furnace Atomic Absorption Spectrometry

提出了以吡咯烷基二硫代氨基甲酸铵(APDC)为螯合剂,乙腈为萃取剂,氯化钠为无机盐的双水相萃取-连续光源石墨炉原子吸收光谱法测定水样中痕量锑的方法。优化的双水相萃取Sb^(3+)的条件如下:螯合反应体系酸度为pH 4,0.5 mL的2 g·L^(-1)APDC储备溶液,1.6 mL的乙腈,1.2 g的氯化钠,反应时间为20 min。在此试验条件下,Sb^(3+)的质量浓度在1.00~20.00μg·L^(-1)内与对应的吸光度呈线性关系,检出限(3 s/k)为0.048μg·L^(-1)。分别对5.00,10.00μg·L^(-1)的Sb^(3+)标准溶液测定10次,测定值的相对标准偏差为4.6%和3.3%。按照标准加入法对实际样品进行回收试验,回收率为95.8%~102%。将此方法用于检测自来水、河水、湖水中的痕量锑,显示这些环境样品中含有部分痕量锑。

A method for the determination of trace antimony in water samples by aqueous two-liquid extraction-continuous light source graphite furnace atomic absorption spectrometry with ammonium pyrrolidine dithiocarbamate(APDC)as chelating agent,acetonitrile as extraction agent and sodium chloride as inorganic salt was proposed.The optimized aqueous two-phase extraction conditions of Sb^(3+)were as follows:the acidity of the chelation reaction system was pH 4,with 0.5 mL of 2 g·L^(-1)APDC reserve solution,1.6 mL of acetonitrile,and 1.2 g of sodium chloride,and the reaction time was 20 min.Under the experimental conditions,linear relationship between the corresponding absorbance and mass concentration of Sb^(3+)was found in the range of 1.00-20.00μg·L^(-1),with detection limit(3 s/k)of 0.048μg·L^(-1).5.00,10.00μg·L^(-1)Sb^(3+)standard solutions were determined 10 times,and RSDs of the determined values were 4.6%and 3.3%,respectively.Test for recovery was made by standard addition method on actual samples,giving results in the range of 95.8%-102%.This method was applied to the determination of trace antimony in tap water,river water and lake water,and some trace antimony was found in these environmental samples.