螯合萃取-石墨炉原子吸收法测定不同产地茜草中痕量铅

Determination of Lead in Rubia tinctorum L. from Different Areas by GFAAS with Chelation-Extraction

用甲基异丁基甲酮(MIBK)萃取吡咯烷二硫代氨基甲酸铵-二乙基二硫代氨基甲酸钠(APDC-DDTC)与Pb形成金属螯合物,然后用石墨炉原子吸收(GFAAS)法测定Pb。探讨了不同螯合剂的螯合效率、螯合剂和萃取剂的用量、pH值等因素的影响。在实验选定最佳条件下,测定了新疆、宁夏、陕西三个产地茜草中的痕量Pb。方法的富集倍数为16.6,相对标准偏差依次为0.046%、0.14%和0.051%,回收率依次为110%、92.7%、91.9%。该方法抗干扰能力强,精密度和准确度良好,可用于中草药中痕量铅的测定。

Lead in rubia samples was chelated with ammonium pyrrolidine dithio-carbamate （APDC）-sodium diethyldithio carbamate （DDTC）,and the thus formed complex was extracted with methyl isobutyl ketone （MIBK）. The concentration of Pb2＋ was determined by using GFAAS method. The effects of chelator,pH value,and the dosage of chelator and extractant were investigated. Under the optimum experimental conditions,the trace lead in Rubia tiuctorum L. from Xiujing,Ningxia and Shanxi was determined. The preconceatration time was 16.6,the relative standard deviation were 0.0046%,0.14% and 0.051%,and the recoveries were 110%,92.7% and 91.9%,respectively. The method showed good anti-interference ability and satisfying precision and accuracy. It is applicable in determining trace lead in Chinese traditional medicine.