建立了分散液液微萃取分离富集-石墨炉原子吸收光谱法测定环境水样中痕量镉的新方法.以二乙基二硫代氨基甲酸钠为螯合剂、四氯化碳为萃取剂、丙酮为分散剂,详细考察了pH值、螯合剂质量分数、萃取剂体积、萃取时间等因素的影响.在优化的实验条件下,方法对水样中镉的检出限为4.2 ng·L-1,线性范围是20～300 ng·L-1,测定结果的相对标准偏差为3.5％,富集倍数达103.将建立的方法应用于三种实际环境水样中镉的检测,加标回收率在92％～ 108％范围内.本方法具有灵敏、准确、快速、环保的特点,是一种分析水样中痕量镉的较好方法.%A novel method for determination of trace amount of cadmium in environmental water samples by graphite furnace atomic absorption spectrometry coupled with dispersive liquid-liquid micro-extraction was developed. Sodium diethyldithiocarbamatre (DDTC), carbon tetrachloride and acetone were used as the chelating agent, extraction solvent and dispersive solvent, respectively. The effects of sample pH, DDTC concentration, extractant volume and extraction time on cadmium extraction were investigated in detail. It was found that under the optimal conditions, the limit of detection for cadmium was 4.2 ng-L"1, the relative standard deviation (RSD) was 3.5%, and the linear range was between 20 and 300 ng-L"1. Three water samples were analyzed by the established method with spiked recoveries of 92-108%. The proposed analytical technique is sensitive, accurate, rapid and environmentally friendly.
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