Mommers John, Ritzen Erik, Dutriez Thomas, van der Wal Sjoerd
DSM Resolve, P.O. Box 18, 6160 MD Geleen, The Netherlands; Analytical Chemistry and Forensic Analyses Group, Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.
DSM Resolve, P.O. Box 18, 6160 MD Geleen, The Netherlands.
J Chromatogr A. 2016 Aug 26;1461:153-60. doi: 10.1016/j.chroma.2016.07.052. Epub 2016 Jul 20.
In this paper, a novel, and easy to perform, retention time locking procedure for locking primary and secondary retention times of detector signals in comprehensive two-dimensional gas chromatography (GCxGC) dual-detection is proposed and its advantages are demonstrated and discussed. The dual detection retention time locking procedure is a 2-step process for a GCxGC system in which the effluent of the primary column is split, by using a pressure regulated splitter, towards the GCxGC modulator using two identical secondary GC columns of which one is installed in the main GC oven and the other is installed in a secondary GC oven. The first step of the locking procedure is to minimize the secondary retention time difference between both detectors of a compound, which has a retention factor (k) close to 0. This is done by stepwise altering the effective secondary column length, simply by sliding the secondary column, which is installed in the main oven, forwards or backwards through the modulator. The second step is to minimize the secondary retention time difference of a compound which has a significant retention in both dimensions. This is done by stepwise altering the secondary oven temperature rate. This locking procedure was successfully demonstrated for the analysis of a diesel sample by GCxGC coupled to a time of flight mass spectrometer (TOFMS) and a nitrogen chemiluminescence detector (NCD) and by GCxGC coupled to a TOFMS and a flame ionization detector (FID). For all compounds the average absolute secondary retention time differences between the NCD or the FID and the TOFMS detectors were 0.03, and 0.07s, respectively, which are significantly less than the average peak widths at half heights, which was 0.2s.
本文提出了一种新颖且易于实施的保留时间锁定程序，用于锁定全二维气相色谱（GCxGC）双检测中检测器信号的一级和二级保留时间，并展示和讨论了其优势。双检测保留时间锁定程序是GCxGC系统的两步过程，其中一级柱的流出物通过压力调节分流器分流，使用两根相同的二级气相色谱柱流向GCxGC调制器，其中一根安装在主气相色谱炉中，另一根安装在二级气相色谱炉中。锁定程序的第一步是最小化保留因子（k）接近0的化合物在两个检测器之间的二级保留时间差异。这通过逐步改变有效二级柱长度来实现，只需将安装在主炉中的二级柱在调制器中向前或向后滑动即可。第二步是最小化在两个维度上都有显著保留的化合物的二级保留时间差异。这通过逐步改变二级炉温速率来实现。通过将GCxGC与飞行时间质谱仪（TOFMS）和氮化学发光检测器（NCD）联用以及将GCxGC与TOFMS和火焰离子化检测器（FID）联用，成功地证明了该锁定程序可用于柴油样品的分析。对于所有化合物，NCD或FID与TOFMS检测器之间的平均绝对二级保留时间差异分别为0.03和0.07秒，这明显小于半高平均峰宽0.2秒。
