Offline LC‐GC×GC in combination with rapid‐scanning quadrupole mass spectrometry

Abstract

The present research is focused on the offline combination of normal-phase LC to double-oven GC×GC-quadrupole MS. Initially, a diesel sample was subjected to automated LC×GC in order to define the elution windows of four fractions, viz., saturated hydrocarbons, monocyclic aromatics, dicyclic aromatics, tri- + tetracyclic aromatics; each fraction was collected exploiting the LC system in a further analysis and subjected to large-volume-injection-GC×GC analysis using an apolar–polar column combination. The GC×GC operational conditions were tuned in relation to the specific separation requirements of each heart-cut. The main benefits of what can be defined as offline LC-GC×GC were: (i) the high first-dimension LC selectivity; (ii) the injection of high sample amounts in the GC×GC system, enabling the detection and quantification of a series of low-amount diesel constituents; (iii) improved GC×GC operational conditions for each heart-cut with respect to direct GC×GC.