样品质量对EA-IRMS法测量硫同位素组成的影响

摘要

研究不同样品质量对EA-1RMS法测量硫同位素组成的影响,通过对质量为47～1124 μg国家标准物质硫化银GBW04414质量数66、65、64的SO2+和质量数50、49、48的SO+测试,结果表明该方法精密度受到样品质量的影响较大.当δ34S的精密度要求标准偏差＜±0.2‰时,控制硫化银的样品质量应为(420±50) μg,即样品的硫含量应为(54±6)μg为佳.国家标准物质GBW04414的质量在380～420 μg之间,δ34S和δ33S的精密度较高,标准偏差分别为±0.14‰、±0.09‰,精密度满足国家标准测量精度＜±0.2‰的实验要求.%This work was aim to study the influence of sample mass on the measurement of sulfur isotopic composition by EA-IRMS method.Based on the national reference materials of silver sulfide GBW04414,we weighted the sample mass between 47 and 1124 μg to measure mass number 66,65,64 of SO2+and mass number 50,49,48 of SO+,the results showed that the accuracy of this method was obviously affected by the sample mass.When the standard deviation of the δ34S is low to ±0.2 ‰,the mass of silver sulfide should be 420 ±50 μg,as that the sulfur content of the sample should be 54 ±6 μg.When the mass of the national reference material GBW04414 is between 380-420 μg,the standard deviation of δ34S and δ33S is ±0.14 ‰ and ±0.09 ‰ respectively,and this accuracy can meet the experimental requirements of the national standard which should be low to ± 0.2％.