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乙二胺四乙酸(EDTA)及其二钠盐(EDTA-Na_2)常含有微量次氮基三乙酸(NTA)。NTA的含量是控制化学试剂EDTA质量的主要指标之一,对EDTA中的微量NTA的测定已经引起人们的关注。Nb(V)-二甲酚橙褪色比色法已用于EDTA中微量NTA的例行分析。Leblanc、Farrow等曾报道,以Cd-NTA络合物的形式极谱法测定EDTA中的NTA,但这些方法手续较繁,灵敏度不够高。我们在文献[2,4]工作的基础上,重新讨论了极谱法测定EDTA中微量NTA的问题,制定了示波极谱法测定
Ethylenediaminetetraacetic acid (EDTA) and its disodium salt (EDTA-Na_2) often contain traces of nitrilotriacetic acid (NTA). The content of NTA is one of the main indexes to control the quality of chemical reagent EDTA, and the determination of trace NTA in EDTA has attracted people’s attention. The Nb (V) -xylphenol orange fading colorimetric method has been applied to the routine analysis of trace NTA in EDTA. Leblanc, Farrow et al. Reported that the determination of NTA in EDTA by the polarographic method of Cd-NTA complex, however, these methods are complicated and the sensitivity is not high enough. Based on the work in [2] and [4], we reexamined the problem of polarographic determination of trace NTA in EDTA and developed the method of oscillopolarographic determination