Development of surface ionization organic mass spectrometer (SIOMS) for the application to forensic toxicology.

最近，药物滥用问题在日本变得更加重要；越来越多的年轻人使用滥用药物。因此，建立灵敏的体液中滥用药物的检测方法具有重要意义。表面电离（SI）是叔氨基化合物在白炽灯表面转化正离子的一种现象；表面电离有机质谱法（SIOMS）是SI作为一种电离方法的应用。SIOMS仪器是一个四极杆质谱仪（MS），它被修改为可用于电子冲击（EI）和SI模式。对于硅离子源，直接入口探头使用铼灯丝改造成硅组件，并插入到EI离子源室的中心。我们首先尝试用SIOMS检测人体体液中的PCP；其检出限分别为0.05 ng/ml（质谱法）和0.01 ng/ml（选择性离子监测法），分别是以往GC/MS方法的5 ~ 200倍和25 ~ 1000倍。此外，SI模式下的背景噪声要比EI模式小得多。SIOMS对戊唑嗪、MPTP及其类似物、哌替啶和三环抗抑郁药的敏感性也要高得多。pentazocine在6.25 ~ 100 ng/ml范围内呈线性关系，在全血和尿样中检出限为0.5 ng/ml；SIOMS在SIM模式下对戊唑嗪的灵敏度比EI-SIM高约60倍。因此，SIOMS非常推荐用于检测人体体液中含有叔氨基的一些微量滥用药物。在未来，我们计划用串联SIOMS分析化合物的破碎过程。

Recently, the issue of drug abuse has become more important in Japan ; more youngsters use abused drugs. Therefore, it is important to establish sensitive determination methods for abused drugs in human body fluids. Surface ionization (SI) is a phenomenon in which tertiary amino compounds convert positive ions on an incandescent surface ; surface ionization organic mass spectrometry (SIOMS) is an application of SI as an ionization method. The SIOMS instrument was a quadrupole mass spectrometer (MS) , which was modified to be usable in both electron impact (EI) and SI modes. For an SI ion source, the direct inlet probe was remodeled to a SI assembly using a rhenium filament, and it was inserted to the center of an EI ion source chamber.We first tried to detect PCP in human body fluids by SIOMS ; its detection limits were 0.05 ng/ml (in mass chromatography, MC) and 0.01 ng/ml (in the selected ion monitoring, SIM) , which were 5 - 200 (in the MC) and 25 - 1000 (in the SIM) times higher compared to previous GC/MS methods. Moreover, background noises were much smaller in the SI mode than the EI mode. SIOMS also gave much higher sensitivity in pentazocine, MPTP and its analogues, pethidine and tricycle antidepressants. In the case of pentazocine, the calibration curves were linear in the range of 6.25 - 100 ng/ml and the detection limits were 0.5 ng/ml in whole blood and urine sample ; the sensitivity for pentazocine obtained by SIOMS in the SIM mode was about 60 times higher than those obtained by EI-SIM. Consequently, SIOMS is highly recommendable for the detection of trace amounts of some abused drugs containing tertiary amino groups in human body fluids.In the future, we are planning to analyze the process of fragmentation of a compound by tandem SIOMS.