二乙胺荒酸钠–四氯化碳萃取连续光源原子吸收法测定磷酸一二钙中的痕量铅、镉

建立连续光源原子吸收分光光度法同时测定磷酸一二钙(MDCP)中铅、镉的方法。MDCP经盐酸消解后,以氢氧化钠溶液调节p H为11,加入KCN作为掩蔽剂,用二乙氨荒酸钠–四氯化碳络合铅、镉离子,再经CCl_4进一步萃取浓缩,采用连续光源原子吸收分光光度法测定铅、镉的含量。该方法铅、镉的检出限为1,0.5 mg/kg;用于不同批次MDCP产品测定,铅、镉测定结果的相对标准偏差分别为3.58%,6.91%(n=11);铅、镉的加标回收率分别为88.9%~104.7%,91.0%~106.4%。该法可用于MDCP中痕量铅、镉的同时测定。

Determination of Lead and Cadmium in MDCP by Continuous Light Source Atomic Absorption Spectrometry with Ditiocarb Sodium-CCl4 Extraction

A method was established for determination of lead, cadmium in MDCP by continuous light source atomic absorption spectrophotometry. After being digested by hydrochloric acid, the digestion solution was adjusted to pH 11 with NaOH solution. KCN being as a masking agent, Pb2+ and Cd2+ in sample solution were chelated by DDTC-Na, extracted and enriched by CCl4, the contents of lead and cadmium were determined by continuous light atomic absorption spectrophotometry. The detection limits of lead and cadmium by this method were 1 mg/kg and 0.5 mg/kg, respectively. The relative standard deviation (RSD) for determination results of MDCP products of different batch were 3.58% and 6.91%(n=11), the recovery rate were 88.9%-104.7% and 91.0%-106.4% for Pb2+ and Cd2+, respectively. This method can be used for determination of trace lead and cadmium in MDCP.