中文摘要：

使用改进的巯基棉分离流程和^74硒-^77硒双稀释剂，在氢化物（HG）-多接收器电感耦合等离子体质谱仪（MC—ICP—MS）实现了高精度硒同位素组成的测定。巯基棉用于分离样品基质中的硒，随后使用HNO3＋H2O2消除干扰的有机质，^74硒-^77硒双稀释剂校正样品分离和质谱测定过程中的硒同位素质量分馏。硒标准溶液NIST SRM5149和MH495几个月的测定表明，该方法的外精度为0．1‰（2σ），样品的外精度为0．15‰～0．2‰（2σ）。以TCF分离硒的平均回收率85％计算，最小硒需要量为20ng。实验结果以相对于NIST SRM3149的δ^82／76Se表达，δ^82/76MH98/SRM3149=-3．44±0．1‰（2σ），优于已发表的数据δ^82/79MH495/SRM3149=-3．04±0．5‰。测定样品的δ82/76 SRM3149为-13．53‰～11．37‰，为硒同位素在环境、农业、生命和地球科学中的拓展应用与发展奠定了基础。

英文摘要：

A method was developed for high precision measurement of selenium isotopes by hydride generatormultiple collector inductively couple plasma mass spectrometry （HG-MC-ICP-MS） using ^74Se-^77Se double spike and modified thio-cotton purification procedures. Thio-cotton was first used to chemically separate selenium from sample matrix, followed by removing unknown organic matter from thio-cotton using HNO3 ＋ H2O2 for possibly interfering hydride generation. ^74Se-^77Se double spike allowed us to effectively correct analytical isotope fractionation during sample chemical purification and mass spectrometry measurement. The external reproducibility for standard NIST SRM3149 and MH495, nature sample were 0. 1‰ （2σ） and 0. 15 ‰ - 0. 2‰（2σ） over the course of several months, respectively. Based on the average yield （85 % ） of Se separation using thio-cotton, the minimum quantity of Se needed for isotope analysis was approximately 20 ng. Se isotope ratios was reported relative to NIST SRM3149, house standard δ^82/76 MH495/RM3149 = （ - 3.44 ± 0.1 ‰） （2σ）, which was in agreement with previously published data δ^82/76MH495/SRM3149 =（ - 3. 04 ± 0. 5 ） ‰ from sample-standard bracketing techniques. Selenium isotopes were measured in several sedimentary samples with a range in δ^82/76 Se between -13.53 ‰ and 11.37‰ relative to NIST SRM3149, these results indicated a wide perspective application of Se isotopes in environmental, geological, agrieuhural and life field.