石脑油中杂质元素的快速质谱分析

Rapid Determination of Impurity Elements in Naphtha by Inductively Coupled Plasma Tandem Mass Spectrometry

研究建立了石脑油中杂质元素的快速分析方法。石脑油样品经无水乙醇简单稀释后,直接采用电感耦合等离子体串联质谱(ICP-MS/MS)法测定其中的Si、P、S、Cl。针对复杂基质测定过程中存在的多原子离子干扰,采用MS/MS模式,通过向碰撞反应池(CRC)中加入O_2为反应气,使^(28)Si^+、^(31)P^+、^(32)S^+分别与O_2发生质量转移反应生成^(28)Si^(16)O_2^+、^(31)P^(16)O^+、^(32)S^(16)O^+,从而消除多原子质谱干扰;通过向碰撞反应池(CRC)中加入H_2,使^(35)Cl^+与H_2发生质量转移反应生成H_2^(35)Cl^+消除干扰。^(28)Si^(16)O_2^+、^(31)P^(16)O^+、^(32)S^(16)O^+、H_2^(35)Cl^+的检出限分别为0.15、0.058、0.26和3.96μg/L。为验证方法的准确性,分析了国际标准参考物质润滑油(NIST SRM 1848)中Si、P、S、Cl的含量,所测定的结果与标准参考物质所提供的标准值无显著性差异,相对标准偏差(RSD)小于3.7%,表明所建立的分析方法准确可靠,适合于石脑油中Si、P、S、Cl 4个杂质元素的快速测定。

Rapid analysis method has been established for the determination of impurity elements in naphtha.Firstly,the sample is diluted with absolute ethyl alcohol,and then Si,P,S and Cl elements are analyzed by inductively coupled plasma tandem mass spectrometry(ICP-MS/MS).It suggests that ^(28)Si^(16)O_2^+,^(31)P^(16)O^+ and ^(32)S^(16)O^+ species are generated via the reaction among ^(28)Si^+,^(31)P^+ and ^(32)S^+ with O_2,respectively,in the MS/MS mode by adding O_2 as reaction gas to the collision reaction cell(CRC).Thus,to eliminate the existence and interference of the complex matrix polyatomic interferences,H_2 is added to the CRC as the reaction gas,with the generation of H352 Cl+species via the mass shift reaction between ^(35)Cl^+ and H_2.The detection limits of ^(28)Si^(16)O_2^+,^(31)P^(16)O^+,^(32)S^(16)O^+ and H_2^(35)Cl^+ are 0.15μg/L,0.058μg/L,0.26μg/L,3.96μg/L,respectively.The accuracy of the analytical method is assessed by the analysis of the standard reference materials NIST SRM 1848(trace elements in lubricating oil),which shows no significant difference between the measured values and the certified values.The relative standard deviation(RSD)is less than 3.7%.The measurement procedure is suitable for analyzing Si,P,S and Cl elements in naphtha.