中心切割式多维气相色谱/质谱系统中中点限流器的改进及其在卷烟烟气中苯并[a]芘检测中的应用

对多维气相色谱的核心部件中点限流器进行了改进,用一段0.25mm i.d.毛细管柱取代石墨限流管,Y形玻璃压合连接器取代两孔石墨垫,显著提高了一维色谱保留时间的稳定性,保证了中心切割范围的准确性,且消除了石墨对苯并a]芘的吸附残留。同时,将本系统应用于卷烟烟气中苯并a]芘的检测。采用剑桥滤片捕集烟气粒相物,环己烷萃取,以氘代苯并a]芘为内标,直接用中心切割式多维气相色谱/质谱(MDGC/MS)法测定。该法线性关系良好,其线性范围为1.47～29.4μg/L(r2=0.999 9);重复性好,测得实际样品中苯并a]芘含量的相对标准偏差(RSD)为1.94%;回收率为90.74%～101.86%;检出限和定量限分别为0.31ng/支及1.03ng/支,可以满足检测要求。应用本系统对2R4F参比卷烟烟气中苯并a]芘进行了检测,结果与文献报道值基本一致。

Modification of mid-point restrictor of heart cut multidimensional gas chromatography-mass spectrometry system and its application in analysis of benzo[a]pyrene in cigarette smoke

The mid-point restrictor, known as the key spare part of multidimensional gas chromatography (MDGC), was modified and applied in the determination of benzo［a］pyrene in cigarette smoke. The graphite restrictor was replaced by a 0.25 mm i.d. fused silica open tubular and the two-hole graphite ferrule was replaced by a press-fit glass Y-splitter to improve the stability of retention time on the 1st dimensional column and eliminate the carry-over effects of graphite. The cigarette samples were prepared as follows: The mainstream cigarette smoke collected on Cambridge pad was extracted with cyclohexane, then the extractant was analyzed by heart cut MDGC-mass spectrometry(MS) directly with benzo［a］pyrene-d12 as internal standard. The method was proved to be simple, sensitive, fast and reliable with good linearity (linear range of 1.47-29.4 μg/L, r2 of 0.9999), reproducibility (relative standard deviation (RSD) of 1.94%), recovery (90.74%-101.86%) and low quantitative and qualitative detection limits. Moreover, the amount of benzo［a］pyrene in the 2R4F Kentucky reference cigarette smoke obtained by this method was close to that reported in literature.