Chemical and Laser Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.
J Am Soc Mass Spectrom. 1993 Oct;4(10):774-81. doi: 10.1016/1044-0305(93)80034-V.
The feasibility of using an ion trap detector for real-time monitoring of volatile organic compounds in atmospheric samples is demonstrated. Detection limits in the low part-per-million to low part-per-billion ranges are achieved with an operating dynamic range of at least 5 orders of magnitude. Sample introduction through semipermeable membranes and molecular leak valves was evaluated. The membrane introduction method provided detection limit enhancements of 10-300 times over the molecular leak method. The effects of partial pressure from air and helium buffer gas were studied, and it was determined that, for optimum amounts of air, the helium buffer gas had no apparent effect on sensitivity or resolution. Air acts as the buffer gas to enhance ion signals by collisionally damping ion motion. The enhancement of molecular ion abundance at high partial pressures of air is postulated to be due to charge exchange and possibly collisional stabilization reactions.
本文展示了使用离子阱检测器实时监测大气样品中挥发性有机化合物的可行性。通过半渗透膜和分子泄漏阀进行样品引入的方法进行了评估。与分子泄漏方法相比，膜引入方法提供了 10-300 倍的检测限增强。研究了空气和氦缓冲气体分压的影响，结果表明，对于最佳的空气量，氦缓冲气体对灵敏度或分辨率没有明显影响。空气作为缓冲气体通过碰撞阻尼离子运动来增强离子信号。假设在高空气分压下，分子离子丰度的增强是由于电荷交换和可能的碰撞稳定反应。
