微波消解-固相萃取-石墨炉原子吸收法测定复配乳化增稠剂中的铅和镉

Determination of lead and cadmium in complex emulsifying thickeners by microwave digestion-solid phase extraction-graphite furnace atomic absorption spectrometry

中文关键词:  微波消解法  固相萃取法  石墨炉原子吸收光谱法  复配乳化增稠剂  铅  镉

英文关键词:microwave digestion method  solid phase extraction  graphite furnace atomic absorption spectrometry  complex emulsifier-thickener  lead  cadmium

中文摘要:

      目的 建立微波消解-固相萃取-石墨炉原子吸收法检测复配乳化增稠剂中铅和镉的分析方法。方法 样品经过微波消解后, 过亚氨基二乙酸型固相萃取柱净化, 用1.0%硝酸溶液进行洗脱, 定量收集洗脱液。石墨炉原子吸收测量样品时加入磷酸二氢铵-氯化钯作为化学改进剂, 采用氘灯背景校正的方式对铅、镉进行检测。结果 铅和镉元素在一定浓度范围内线性关系良好, 相关系数分别为0.9994和0.9991。铅在5、10和 20.0 μg/L添加水平的回收率为81.2%~102.9%, 精密度的相对标准偏差为2.70% (n=7), 检出限为0.900 μg/L; 镉在0.5、1.0和2.0 μg/L添加水平的回收率为84.0%~107.0%, 精密度的相对标准偏差为4.18%(n=7), 检出限0.037 μg/L。结论 该方法耗时短、稳定性好、灵敏度高, 尤其是固相萃取柱的净化作用以及基体改进剂的使用, 有效降低了背景干扰, 适用于复配乳化增稠剂中铅、镉的测定。

英文摘要:

      Objective To establish a method for the determination of lead and cadmium in complex emulsified-thickener by microwave digestion-solid phase extraction-graphite furnace atomic absorption spectrometry (MD-SPE-GFAAS). Methods After microwave digestion, the sample was purified by a solid phase extraction column with iminodiacetic acid, eluted with 1.0% nitric acid solution, and the eluent was collected quantitatively. When lead and cadmium were measured by graphite furnace with deuterium lamp background correction, NH4H2PO4-PdCl2 was added as chemical modifier. Results Lead and cadmium had a good linear relationship within a certain concentration range, and the correlation coefficients were 0.9994 and 0.9991, respectively. The recovery rates of lead at 5, 10 and 20.0 μg/L addition levels were 81.2%?102.9%, the relative standard deviation of precision was 2.70% (n=7), and the limit of detection was 0.900 μg/L. The recovery rates of cadmium at 0.5, 1.0 and 2.0 μg/L addition levels were 84.0%?107.0%, the relative standard deviation of precision was 4.18% (n=7), and the limit of detection was 0.037 μg/L. Conclusion The method is time-consuming, stable and sensitive, especially the purification of solid phase extraction column and the use of matrix modifier, which effectively reduces the background interference. It is suitable for the determination of lead and cadmium in compound emulsifying-thickener.