In this study, DRO and ORO analysis were carried out on an ultrafast setup that allows completion of GC run in less than 2 min. Calibration was linear from 10 ppm to 500 ppm for both DRO and ORO. Alternative carrier gas (hydrogen) and helium were also tested in this study. To minimize disruption
and maximize automation during carrier gas switching, a Shimadzu gas selector was employed. Data obtained using He or H2 carrier gas were comparable, confirming that H2 is a suitable alternative gas for this analysis. Given the high cost of He nowadays, H2 would be preferable to use as the carrier gas.
The total analysis time per sample was approximately 3.5 min (including sample preparation and column cool down time); this time can be further optimized to less than 3 min per sample when the autosampler AOC-20 overlapping pretreatment function is enabled. This method significantly increases the throughput (by an order of magnitude) when compared to conditions described in EPA 8015 and allows for the analysis of up to 250 samples in a 12-hr work shift. Coupled with Shimadzu’s long-life septa and syringe, up to 1000 injections may be performed without stopping to perform GC maintenance.