高硒环境样品中硒的形态分析方法

在恩施富硒碳质岩和土壤样品中硒矿物学研究的基础上,提出了硒连续化学提取的改进方案。化学操作上定义为7个连续步骤:水溶态(MQ水提取)、可交换态(0.1 mol/L的K2HPO4 KH2PO4,pH=7.0)、有机结合态(0.1 mol/L NaOH)、元素态(1 mol/L Na2SO3溶液)、酸溶性提取态(15%CH3CO2H溶液)、硫化物/硒化物态(1 mol/L CrCl2 HCl溶液)和残渣态硒(HNO3 HF H2O2混合消化液)。使用HG-AFS法检测了各结合态中的硒形态和总硒,上述流程提取硒加和与总硒间显著一致,平均回收率为99.2%,符合平行样品间变异系数低于10%的精度要求。该方法简单易行,能够准确地揭示富硒地质样品中硒的形态信息。

The Method for Analyzing State of Selenium in Se-rich Environmental Samples

On the basis of studying selenium minerals occurred in Se-rich rocks and soils in Yutangba,Enshi County,a modified method of sequential extraction procedure for extracting Se in Se-rich environmental samples was developed.Seven operationally defined Se fractions were named as water- soluble adsorbed,base soluble,elemental,carbonate and amorphous oxides,sulfide/selenide and residue respectively.The Se concentration and its species in each fraction were determined by using HG-AFS method.There is good correlation between the total Se contents in samples and the sum of the Se contents of the sequential extraction fractions.The recovery is ranged from 88.6% to 111.7 with an average of 99.2%.The RSD between samples and duplicates are less than the acceptable precision of 10%.This method is simple and easy to be operated with accuracy and reliability.The information of Se states and fractions in some Se-rich environmental samples collected from high-Se background areas in China could be accurately revealed by the application of this method.