Inference and analysis of xenon outflow curves under multi-pulse injection in two-dimensional chromatography

Multidimensional gas chromatography is widely applied to atmospheric xenon monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). To improve the capability for xenon sampling from the atmosphere, sampling techniques have been investigated in detail. The sampling techniques are designed by xenon outflow curves which are influenced by many factors, and the injecting condition is one of the key factors that could influence the xenon outflow curves. In this paper, the xenon outflow curves of single-pulse injection in two-dimensional gas chromatography has been tested and fitted as a function of exponential modified Gaussian distribution. An inference formula of the xenon outflow curve for six-pulse injection is derived, and the inference formula is also tested to compare with its fitting formula of the xenon outflow curve. As a result, the curves of both the one-pulse and six-pulse injections obey the exponential modified Gaussian distribution when the temperature of the activated carbon columnʹs temperature is 26 °C and the flow rate of the carrier gas is 35.6 mL min−1. The retention time of the xenon peak for one-pulse injection is 215 min, and the peak width is 138 min. For the six-pulse injection, however, the retention time is delayed to 255 min, and the peak width broadens to 222 min. According to the inferred formula of the xenon outflow curve for the six-pulse injection, the inferred retention time is 243 min, the relative deviation of the retention time is 4.7%, and the inferred peak width is 225 min, with a relative deviation of 1.3%.