研究了以季胺盐即氯化三辛基甲基胺的二甲苯溶液为萃取剂，在HCl介质中痕量汞的萃取和分光光度法测定。对萃取、分离定量的最适条件，选用适宜的反萃取剂以及汞的萃取体系进行了详细研究。结果表明，桑德尔灵敏度为4.8×10-4μg/cm2,相比Vw/Vo=40，汞量在0～0.5μg范围内遵守郎伯—比尔定律，成功的建立了一个新的测定痕量汞的方法。“,”The extraction of trace amounts of Hg in amedium of HCl with trioctylmethylammonium chloride in dimethylbenzene and the subsequent spectrophorometric determination is described. The optimum conditions of extraction and separation, appropriate reextractants and the extraction systems of Hg have been investigated. The Sandall Sensitivity is 4.8×10-4μg/cm2. Under a phase ratio of extraction Vw/V0=40, the linear range for the deternination of Hg is 0～5 μg/ml. The method is simple, practical and reproducible.