VOCs在线检测质谱仪单光子电离源的研制

摘要

该文介绍了两个不同结构的真空紫外单光子电离源(SPI),电离源与自制的飞行时间质谱仪(TOFMS)连接实现了对挥发性有机物的在线检测.在搭建的SPI-TOFMS上比较了两个电离源的电离效率之间的差异.虽然轴向SPI本质上不是一个纯粹的单光子电离源,但可明显看出,其电离效率比径向SPI要高约50％.同时还考察了仪器的部分性能指标.在质荷比(m/z)为92位置,质量分辨率达767;在1谱/s分析速度下,检测限低于20×10-9(v/v).实验结果证明该仪器能够用于挥发性有机物的在线检测.%Two vacuum ultraviolet single photon ionization(SPI)sources with different structures were introduced in this paper,and on-line detection of volatile organic compounds(VOCs)was realized by coupling the sources with a homemade time-of-flight mass speclrometer (TOFMS). The difference of ionization efficiency between the two sources was compared on the installed SPI-TOFMS. Obviously, the axial SPI, whose ionization efficiency was approximate 50% higher than the radical one,was not a pure SPI source in essence. Some performance indices of this instrument were also investigated at the same time. A mass resolution power of 767 was reached al location of mass-to-charge ratio (m/z)of 92;the limit of detection for toluene was 20×10-9 (v/v)at the state of 1 spectrum/s analytical speed. It was demonstrated by the experimental results that this instrument can be using for on-line detection of VOCs.