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

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

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。

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,r^2 of 0.999 9）,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.