Nitrogen and hydrogen as alternatives to helium using wide-bore columns in preparative multidimensional gas chromatography

Abstract

Wide-bore capillary columns (0.53 mm I.D.) are frequently employed in preparative gas chromatography due to their enhanced sample capacity than the micro-bore counterparts. However, the increased carrier gas flow rates required, especially in multidimensional separations, leads to elevated consumption. Helium is the most used carrier gas thanks to its superior chromatographic performance and inertness, which mitigates safety concerns in routine use. However, helium has experienced supply shortages and rising costs in recent years. This study aimed to evaluate more sustainable carrier gases than helium in preparative multidimensional gas chromatography. In the first stage, the chromatographic performance of nitrogen, hydrogen, and helium was compared on columns equipped with diverse stationary phases using GC-FID. In the second step, the performances of hydrogen and nitrogen were benchmarked against helium in a prototype preparative multidimensional gas chromatographic system. A lemon essential oil was utilized to assess the impact of these carrier gases. Despite a minor variation in terms of total analysis time, comparable chromatographic profiles were achieved with each carrier gas. Our findings indicate that hydrogen and nitrogen, particularly the latter owing to its inherent inertness and safety profile, can represent viable alternatives to helium in preparative multidimensional gas chromatography. These gases offer comparable chromatographic performance while addressing the helium's increasing costs and supply constraints.