Development of An Online LC-LVI-GC × GC System: Design and Preliminary Applications

Abstract

The identification of unknown compounds is of fundamental importance for a range of applications in chromatography including, but not limited to, environmental pollution, food/natural product analysis, metabolomics, sports testing, petrochemicals and biofuel analysis. Critical to the success of each application is the ability to separate the compounds of interest, both from each other and the sample matrix, which may be present at concentrations orders of magnitude higher than the analyte(s). Selectivity and sensitivity are key to such analyses and both may be increased by the use of multiple dimensions of separation. Here, we report on the construction of an online, liquid chromatography hyphenated large volume injection, cryogenically modulated, multi-dimensional gas chromatography (LC-LVI-GC × GC) system for the characterisation of complex matrices using existing instruments that are common in most analytical laboratories. We detail the design of the instrument and demonstrate its performance and potential on a range of sample types. The combination of the LC, and large volume injection cryogenic GC × GC, was found to lead to a high selectivity and peak capacity with little sample preparation needed, but with a trade of a large sample run time of ~40 (but up to ~60) minutes in each case. The system therefore has great potential for the targeted and untargeted analysis of very complex sample types.