以芳香族重氮盐为电离试剂的常压热解化学电离质谱法的初步研究

首次提出采用苯胺、1-幕胺、H-酸重氮盐对甲苯、萘、蒽等稠环芳烃类化合物进行常压热解化学电离质谱研究，考察了热解温度、升温速率、重氮盐用量等对初级离子信号的影响。探讨了常压热解化学电离的一般机理，对所获得的稠环芳烃的自由基阳离子进行了二级质谱鉴定，可以通过二级质谱来对某些同分异构体进行鉴定。该方法对α-苯并蒽的检测限为10fg．可望在无须样品预处理的情况下对包括稠环芳烃和氨基酸在内的非极性和极性化合物进行质谱分析。

The Primary Study of Atmospheric Pressure Thermal Dissociation Ionization Mass Spectrum using Aromatic Diazoium Salt as Ionization Reagent

A novel concept using the radical cation created by thermal dissociation of phenyldiazonium chloride for direct chemical ionization of both non-polar and polar compounds at atmospheric pressure is presented. An atmospheric pressure thermal dissociation chemical ionization (APTDCI) source is constructed and characterized by u-sing phenyldiazonium chloride as thermal dissociation reagent and toluene as analyte. Under the optimized working conditions, a series of polycylic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene, triphenylene and benza]-anthracene are ionized in APTDCI source to give dominant peak corresponding to radical cation or protonated molecules when H-acid diazonium salt is used as reagent in MS spectra, demonstrating the basic performance of the APTDCI source for non-polar compounds. The detection limit of benz a]-anthracene is 10 fg. Serine, an amino acid of significant importance in life evolution, is employed as an example to show the capability of APRDCI source for the polar compounds. It is deduced that APRDCI can be applied to ionize analytes, both non-polar and polar compounds, in atmospheric pressure without complicated sample pretreatment. All the data are validated in tandem mass spectra of interested ions in LTQ mass spectrometer by pollision-induced dissociation. The mechanism of thermal dissociation chemical ionization will be discussed briefly.