中文摘要：

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（0.1mol/L的K2HPO4＋KH2PO4,pH=7.0）、有机结合态（0.1mol/L NaOH）、元素态（1mol/L Na2SO3溶液）、酸溶性提取态（15%CH3CO2H溶液）、硫化物/硒化物态（1mol/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。

英文摘要：

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.