Flow-switching device for comprehensive two-dimensional gas chromatography

A simple flow-switching device has been developed as a differential flow modulator for comprehensive two-dimensional gas chromatography (GC×GC). The device is assembled from tubing, four tee unions, and a solenoid valve. The solenoid valve is located outside the oven of the gas chromatograph and is not in the sample path. The modulation technique has no inherent temperature restrictions and passes 100% of the primary column effluent to the secondary column(s). Secondary peaks are produced with widths at half maximum less than 100 ms when operating in GC×2GC mode with a 2.0 s modulation period. The efficacy of this approach is demonstrated through the analysis of a standard mixture of volatile organic compounds (VOCs) and diesel fuel.