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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NISTSRM3149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NISTSRM3149的δ82/76Se表达,δM82H/74965/SRM3149=-3.44±0.1‰(2σ),优于已发表的数据δ8M2H/74965/SRM3149=-3.04±0.5‰。测定样品的δ8S2R/M736149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。
High-precision selenium isotope composition determination was achieved on a hydride (HG) -multiple receiver inductively coupled plasma mass spectrometer (MC-ICP-MS) using an improved thiol-cotton separation protocol and 74 Se-77 selenium double diluent. Sulfhydryl cotton is used to separate selenium in the sample matrix, followed by the removal of interfering organic matter with HNO3 + H2O2, 74 Se-77 selenium double diluent to correct mass separation of selenium isotopes during sample separation and mass spectrometry. The measurement of selenium standard solution NISTSRM3149 and MH495 for several months showed that the external accuracy of the method was 0.1 ‰ (2σ) and the external accuracy of the sample was 0.15 ‰ -0.2 ‰ (2σ). The average recovery of selenium by TCF 85%, the minimum selenium requirement of 20ng. The experimental results are expressed as δ82 / 76Se relative to NISTSRM3149, with δM82H / 74965 / SRM3149 = -3.44 ± 0.1 ‰ (2σ) better than the published data δ8M2H / 74965 / SRM3149 = -3.04 ± 0.5 ‰. The measured δ8S2R / M736149 is -13.53 ‰ ~ 11.37 ‰, which lays the foundation for the application and development of selenium isotopes in environment, agriculture, life and earth sciences.