The applicability of a large-volume injection (LVI) system for quantitative analysis of permanent gases O-2 and N-2 using a gas chromatograph/barrier discharge ionization detector

摘要

To develop accurate quantitation methods for two major permanent gases, N-2 and O-2, 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 similar to 2090 (O-2) and 791 similar to 7910 (N-2); (2) moderate, 2090 similar to 20,900 (O-2) and 7910 similar to 79,100 (N-2); and (3) high, 20,900 similar to 209,000 (O-2) and 79,100 similar to 791,000 (N-2)). 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 evaluatedwith 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 similar to 500 ng for O-2 (38.4 similar to 557 ppm) and 24 similar to 2230 ng for N-2 (195 similar to 2105 ppm).