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    低共熔溶剂-分散液液微萃取-连续光源石墨炉原子吸收光谱法测定水体和大气颗粒物中的痕量镉

    Determination of Trace Cadmium in Water Body and Atmospheric Particles by Continuous Light Source Graphite Furnace Atomic Absorption Spectrometry with Deep Eutectic Solvent and Dispersive Liquid-Liquid Microextraction

    • 摘要: 取10 mL处理后的样品(pH 6.0)置于15 mL离心管中,加入0.2 mL 2 g·L−1吡咯烷基二硫代氨基甲酸铵溶液和0.3 mL低共熔溶剂(由物质的量比1∶1∶1的壬酸-癸酸-十二酸混合溶液制备而成),涡旋3 min,超声3 min,离心4 min,收集0.1 mL上层有机相置于1 mL石墨炉自动取样杯中,采用连续光源石墨炉原子吸收光谱法测定其中镉(以Cd2+计)的含量。结果表明,镉的质量浓度在0.05~3.00 μg·L−1内与对应的吸光度呈线性关系,检出限(3s/k)为0.01 μg·L−1。对不同样品溶液测定,测定值的相对标准偏差(n=10)均小于7.0%。按照标准加入法对实际样品进行回收试验,回收率为96.6%~103%。将此方法用于检测水体和大气颗粒物中的痕量镉,得到水体中镉的检出量为0.105~0.622 μg·L−1,大气颗粒物中镉的检出量为0.090~0.168 μg·L−1

       

      Abstract: The processed sample (pH 6.0, 10 mL) was taken and placed in a 15 mL-centrifuge tube. 0.2 mL of 2 g·L−1 ammonium pyrrolidine dithiocarbamate solution and 0.3 mL of deep eutectic solvent (prepared by the mixed solution of nonanoic acid, decanoic acid and dodecanoic acid at a molar ratio of 1∶1∶1) were added. The mixture was vortexed for 3 min, ultrasound for 3 min, and centrifuged for 4 min. 0.1 mL of upper organic phase was taken and placed in a 1 mL-graphite furnace automatic sampling cup, and cadmium (calculated as Cd2+) was determined by continuous light source graphite furnace atomic absorption spectrometry. As shown by the results, linear relationship between the corresponding absorbance and mass concentration of cadmium was found in the range of 0.05-3.00 μg·L−1, with detection limit (3s/k) of 0.01 μg·L−1. RSDs (n=10) of the determined values for different sample solutions were less than 7.0%. Test for recovery was made by standard addition method on actual samples, giving results in the range of 96.6%-103%. This method was applied to the determination of trace cadmium in water body and atmospheric particles, with detection amounts of cadmium in water body in the range of 0.105-0.622 μg·L−1, and detection amounts of cadmium in atmospheric particles in the range of 0.090-0.168 μg·L−1.

       

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