DSM Resolve, 6160 MD Geleen, The Netherlands.
J Chromatogr A. 2011 May 27;1218(21):3159-65. doi: 10.1016/j.chroma.2010.08.065. Epub 2010 Sep 21.
In gas chromatography (GC) reproducible retention times are in many cases highly favorable or in some cases even required. In one-dimensional GC, retention time shifts can be eliminated or minimized using a procedure called retention time locking (RTL). This procedure is based on adjusting the (constant) column head pressure. Unfortunately, this RTL procedure cannot be used in comprehensive two-dimensional gas chromatography (GC×GC) given the fact that peaks will shift in both dimensions. Adjusting the column head pressure in GC×GC will only minimize or eliminate the primary retention time shifts. In this paper, a fast and easy to perform, two-step retention time locking procedure for two-dimensional gas chromatography (2D-RTL) is proposed and its feasibility is demonstrated. This 2D-RTL procedure involves adjustment of the column head pressure or constant column flow, followed by the adjustment of the so-called effective secondary column length. The secondary column length is increased or decreased, simply by moving it stepwise through the modulator. It is demonstrated that retention time shifts in both the primary- and secondary-dimension, which may occur after e.g. replacing the column set, can be minimized to less than half peak base width. The proposed 2D-RTL procedure is used successfully for approximately 1 year in our laboratory.
在气相色谱（GC）中，重现的保留时间在许多情况下是非常有利的，在某些情况下甚至是必需的。在一维 GC 中，可以使用称为保留时间锁定（RTL）的程序消除或最小化保留时间偏移。该程序基于调整（恒定）柱头压力。不幸的是，由于在二维气相色谱（GC×GC）中峰会在两个维度上发生偏移，因此无法使用此 RTL 程序。在 GC×GC 中调整柱头压力只会最小化或消除主要保留时间偏移。本文提出了一种快速且易于执行的二维气相色谱（2D-RTL）两步保留时间锁定程序，并证明了其可行性。该 2D-RTL 程序涉及调整柱头压力或恒定柱流，然后调整所谓的有效二级柱长。通过调制器逐步移动，简单地增加或减少二级柱长。结果表明，例如在更换柱组后，可能会发生在主次维度上的保留时间偏移，可以最小化到峰基宽度的一半以下。该提议的 2D-RTL 程序已在我们的实验室中成功使用了大约 1 年。
