提出了石墨炉原子吸收光谱法同时测定环境水样和中药中超痕量铅与镉的方法.以双硫腙为络合剂,在pH 7.0时,用Triton X-114非离子表面活性剂浊点萃取富集样品溶液中痕量铅和镉.用硝酸镁和磷酸二氢铵的混合液作为基体改进剂测定铅和镉,铅和镉的检出限(3s/k)分别为0.138,0.007 μg·L-1,相对标准偏差(n=7)分别为1.90%,2.08%.对于10 mL样品溶液的富集倍数分别为18.3,17.7.应用所提出的方法测定了杨树叶(GBW 07604)和小麦粉(GBW 08503)国家标准样品,测定结果与标准值相符.铅和镉的加标回收率分别为97.8%,94.0%(水样);98.0%,94.0%(中药样).

A new method for simultaneous determination of ultra-trace amounts of lead and cadmium in environmental water and Chinese traditional medicine by GFAAS was proposed in this paper.Ultra-trace of Pb2+ and Cd2+ was extracted from the sample solution in the form of coordination complex with dithizone at pH 7.0 by cloud point extraction with Triton X-114 as a non-ionic surfactant.A mixture of Mg(NO3)2 and NH4H2PO4 was used as matrix modifier.Values of detection limits for Pb and Cd were 0.138 and 0.007 μg·L-1 respectively.Values of RSD′s (n=7) of Pb2+ and Cd2+ were 1.90% and 2.08%,with enhancement factors of 18.3 (Pb) and 17.7 (Cd) in 10 mL sample solution.Standard reference materials of poplar leaf (GBW 07604) and wheat flour (GBW 08503) was analyzed by the proposed method,giving results of Pb and Cd found contents in consistency with the standard values.Values of recovery of Pb and Cd found by standard addition method were 97.8%,94.0% for enviromental water samples and 98.0%,94.0% for Chinese traditional medicine samples respectively.