The applicability of a large-volume injection (LVI) system for quantitative analysis of permanent gases O₂ and N₂ using a gas chromatograph/barrier discharge ionization detector

Abstract

To develop accurate quantitation methods for two major permanent gases, N₂ and O₂, a series of calibration experiments were carried out using a gas chromatograph (GC)/barrier discharge ionization detector (BID) equipped with a large-volume injection (LVI) system. To this end, gaseous working standards (WSs) diluted with helium gas were prepared at ten different concentration levels representing three different concentration ranges (in ppm) in 1-L polyester aluminum (PEA) bags ((1) low, 209~2090 (O₂) and 791~7910 (N₂); (2) moderate, 2090 ~ 20,900 (O₂) and 7910~79,100 (N₂); and (3) high, 20,900~209,000 (O₂) and 79,100~791,000 (N₂)). Cross-calibration experiments for each individual WS were carried out using the loop injection system with four different capacities (0.01, 0.5, 1, and 10 mL). The calibration results were then evaluated with respect to key variables including loop capacity, concentration, and mass quantity. Accordingly, we observed the optimal performance of the BID in terms of sensitivity and linearity (R ² > 0.98) when the WS of the moderate concentration range was analyzed with the small loop (0.01 and 0.5 mL). The method detection limit (MDL) values of the four loop sizes (between 0.01 and 10 mL) were 7~500 ng for O₂ (38.4~557 ppm) and 24~2230 ng for N₂ (195~2105 ppm).