Abstract
An automated system has been developed for continuously monitoring atmospheric C2-C9 hydrocarbons in combination of a sample preconcentration technique and a capillary gas chromatography. The analytical column used is a 0.53 mm I.D. Alumina PLOT column connected to a 0.32 mm I. D. Methyl Silicon column as a resistance in series. A 100-200 ml of air sample is sampled on a trap packed with TENAX GC, activated alumina and activated carbon in series cooled at -10°C by using liquid carbon dioxide. The trapped components are foucused on the head of the analytical column at 40°C followed by determination by temperature-programmed gas chromatography. The analytical run time is 90 min for detecting 0.1 ppb of atmospheric hydrocarbon concentrations. The coefficients of variation are less than 2% of the determined values for consecutive 7 days.
This sytem is useful for on-site monitoring the prominent atmospheric hydrocarbons for long period even in the absence of an operator.
