Portable comprehensive two-dimensional micro-gas chromatography using an integrated flow-restricted pneumatic modulator

摘要

Two-dimensional (2D) gas chromatography (GC) provides enhanced vapor separation capabilities in contrast to conventional one-dimensional GC and is useful for the analysis of highly complex chemical samples. We developed a microfabricated flow-restricted pneumatic modulator (FRPM) for portable comprehensive 2D micro-GC (mu GC), which enables rapid D-2 injection and separation without compromising the D-1 separation speed and eluent peak profiles. D-2 injection characteristics such as injection peak width and peak height were fully characterized by using flow-through micro-photoionization detectors (mu PIDs) at the FRPM inlet and outlet. A D-2 injection peak width of similar to 25 ms could be achieved with a D-2/D-1 flow rate ratio over 10. The FRPM was further integrated with a 0.5-m long D-2 mu column on the same chip, and its performance was characterized. Finally, we developed an automated portable comprehensive 2D mu GC consisting of a 10 m OV-1 D-1 mu column, an integrated FRPM with a built-in 0.5 m polyethylene glycol D-2 mu column, and two mu PIDs. Rapid separation of 40 volatile organic compounds in similar to 5 min was demonstrated. A hybrid 2D contour plot was constructed by using both D-1 and D-2 chromatograms obtained with the two mu PIDs at the end of the D-1 and D-2 mu columns, which was enabled by the presence of the flow resistor in the FRPM.