Translation of a One-Dimensional to a Comprehensive Two-Dimensional Gas Chromatography Method with Dual-Channel Detection for Volatile Organic Compound Measurement in Forensic Applications

Abstract

After its introduction in the early 1990s, comprehensive two-dimensional gas chromatography (GC×GC) has evolved from a separation science research tool to the central component of many industries. Despite the maturity of the technique, some fields remain reluctant to its use in routine applications. In the case of forensic science, some constraints are the strict requirements enforced in forensic laboratories and the time and effort that must be invested for intralaboratory method validation. Concerns may also arise about whether information could be lost when transitioning to a new technique. This study reports on a method translation from conventional one-dimensional (1D) GC to GC×GC, ensuring the integrity of data as conversion is made. The GC was retrofitted with a reverse fill/flush (RFF) flow modulator and equipped with dual-channel detection using a quadrupole mass spectrometer (qMS) and a flame ionization detector (FID). The parallel use of two detectors, where qMS was applied for qualitative identification and FID for quantification, allowed higher flows and slightly wider peaks to be exploited for the analysis of a volatile organic compound (VOC) reference mixture relevant to forensic VOC profiling. Peak quality assessment and calibration curves using GC-qMS and GC×GC-qMS/FID document the transfer and adaptation of the original method without a loss in data quality. Furthermore, the preprocessing and the data analysis processing steps, including calibration and peak quality assessment for each of the three data sets, are explained in detail. This information provides benchmark data for routine laboratories that want to implement a GC×GC approach into routine workflows.

Pilot Study on Exhaled Breath Analysis for a Healthy Adult Population in Hawaii

“…The GC×GC-qMS data were used predominantly for peak identification and the GC×GC-FID data were used for quantitative information. Previous studies describe the use of this dual detection technique in combination with GC×GC and the full workflow used for processing [ 14 , 15 ].…”

“…The peak integration is performed at this stage on the FID data where the acquisition rate is much higher and provides sharp and accurate peak shapes. This approach is outlined in previous publications including detector acquisition rates, number of acquisitions across a peak, and data processing workflows [ 14 , 15 ] and therefore are not described in detail here.…”

“…The dual detection approach enables molecule discovery and identification using the qMS detector and more accurate linear quantification using the FID. Prior studies outline the benefits and data workflows for GC×GC-qMS/FID for VOC analysis [ 14 , 15 ].…”

A non-targeted data processing workflow for volatile organic compound data acquired using comprehensive two-dimensional gas chromatography with dual channel detection

“…The dataset was kept intentionally small for this study to allow users to reproduce the analysis if desired without introducing unnecessary complexity. The instrument method was originally developed for VOC analysis in a pervious publication [5] and this method paper focuses on building upon the data processing workflow.…”

Recent forensic applications of enhanced chromatographic separation methods

“…The comprehensive GC methods can be found in Table 1. Dubois et al [29] have shown that VOCs currently being analyzed via 1D-GC for forensic purposes could be transi-tioned to a 2D-GC method without a drop in the quality of the analysis. It was found that the enhanced chromatographic separation method could be incorporated into routine examinations.…”