原子荧光光谱测定化探样品中砷锑铋汞的两种预处理方法比较

Comparison of two pretreatment methods of AFS on determination of As, Sb,Bi and Hg in geochemical exploration samples

实验研究了原子荧光光谱测定化探样品中As、Sb、Bi、Hg的两种预处理方法。方法一用N2H4·H2O消除王水分解样品溶液中残留的NO-2,直接用硫脲、抗坏血酸混合还原掩蔽剂在比色管中定容,As、Sb、Bi、Hg在同一介质中连续测定;方法二采用王水水浴分解样品,在酸性介质中,以硫脲、抗坏血酸和三氧化二铁溶液将As5+、Sb5+还原后,与Bi、Hg一同上机测定。两种预处理样品方法的测定结果都能达到国家标准要求。

Two methods which can be used for the determination of As, Sb, Bi and Hg in geochemical exploration samples by atomic fluorescence spectrometry（AFS） are introduced in this paper. Method one： N2H4 · H2O is used to eliminate residual NO2- which comes from aqua regia decomposition solution, mixed masking agent of thiourea and as- corbic acid is directly used to reach a constant volume in eolorimetric tube, and finally continuous determination of As, Sb,Bi and Hg is carried out in the same medium. Method two： samples are decomposed with aqua regia. After As5＋ and Sb5＋ are reduced by thiourea-ascorbic acid solution in the acidic medium, they are determined on computer to- gether with Bi and Hg. The results of two pretreatment methods are both in accordance with the national standard.