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本文研究了用聚乙烯吡啶化学修饰电极预富集——石墨炉原子吸收法测定废水中痕量Cr(Ⅵ)和Cr(Ⅲ)的方法.废水中的痕量Cr(Ⅵ)被富集到经聚乙烯吡啶修饰的钨丝电极上,然后放入石墨杯中进行原子吸收测定“Cr(Ⅲ)在碱性条件下经H_2O_2氧化为Cr(Ⅵ),同法测定在pH为4的HCl介质中,测定的线性范围为1～25ng/m1,对含Cr(Ⅵ)10ng/ml的溶液十次平行测定,相对标准偏差为5.4%,检出限0.4ng/ml,二十多种共存离子不干扰测定.样品测定回收率在94～104%之间.
In this paper, a method for the determination of trace Cr (Ⅵ) and Cr (Ⅲ) in wastewater by graphite electrode atomic absorption spectrometry pretreated with poly (vinyl pyridine) modified electrode was studied. Trace Cr (Ⅵ) in wastewater was enriched Cr (Ⅲ) was oxidized to Cr (Ⅵ) by H_2O_2 in alkaline condition, and the same method was used to determine the content of HCl in pH 4 HCl medium , The linear range of determination was 1 ~ 25ng / ml, and the relative standard deviation was 5.4% with the detection limit of 0.4ng / ml for more than 20 kinds of coexisting ions Not interfere with the determination of the sample recovery was 94 ~ 104%.