【摘要】 二次电喷雾电离质谱（Secondary electrospray ionization mass spectrometry, SESI-MS）可实时在线检测人体呼出气中的挥发性有机化合物（Volatile organic compounds, VOCs）,但呼出气中VOCs的电离效率会受到源内气体氛围的影响。本研究在自制SESI源的基础上,以超高分辨质谱（Ultra-high resolution mass spectrometer, UHRMS）为分析技术,以人体呼出气中典型内源性化合物丙酮（Acetone）和吲哚（Indole）,以及典型基质邻苯二甲酸酐（Phthalic anhydride, PA）和邻苯二甲酸二丁酯（Dibutyl phthalate,DP）为目标化合物,初步探究了SESI源内不同气体氛围（氮气（N₂）、二氧化碳（CO₂）、纯净零气（Zero air））对目标VOCs电离效率的影响。结果表明,在SESI源内通入3种纯净气体,可有效提高呼出气中丙酮和吲哚的信号强度和信噪比;同时,由于降低了源内基质含量,可显著减弱基质干扰。3种纯净气体中,通入N₂后的效果最为显著。本研究结果可为SESI源设计及参数设置、呼出气分析方法开发提供重要依据。更多还原

【Abstract】 The secondary electrospray ionization mass spectrometry（SESI-MS） has great potential in acquiring breathomics by in vivo, real-time and direct breath analysis. However, as an ambient source, the ionization efficiency of exhaled volatile organic compounds（VOCs） can be disturbed by the occurrence of indoor VOCs（background matrix） in SESI source. Therefore, we explored the effects of pure gases in the SESI source on the ionization efficiency of typical exhaled endogenous compounds, i.e., acetone and indole, as well as typical background matrix, i.e., phthalic anhydride（PA） and dibutyl phthalate（DP）, by using a homemade SESI source coupled with an ultrahigh resolution mass spectrometer（UHRMS）. The pure gases in this study included nitrogen（N₂, purity 99.999%）, carbon dioxide（CO₂, purity 99.99%） and Zero air（VOCs free, 21% O₂ and 79% N₂ by volume）. The results showed that the presence of all three pure gases could significantly increase the signal intensity and signal-to-noise ratio of exhaled acetone and indole. In contrast, the intensities of matrix interferences PA and DA decrease, because the concentrations of these compounds were diluted by the pure gases. Among three pure gases, the effect of N₂ was most significant. In summary, the results of this study provided helpful information for SESI source design and parameter setting, which was an important prerequisite for the development of qualitative and quantitative methods for the detection of exhaled VOCs by using SESI-MS.更多还原