Analysis of Trace (mg/kg) Thiophene in Benzene Using Two-Dimensional Gas Chromatography and Flame Ionization Detection Application

A two-dimensional gas chromatography system using a simplified Deans switch design is used for the analysis of trace (mg/kg) thiophene in benzene. This system uses two GC columns of different selectivity, INNOWax and PLOT Q, to completely separate the thiophene from the interfering sample matrix. Because of this high resolution, standard flame ionization detectors can be used in place of more expensive and complex sulfur selective detectors. The system provides precise qualitative and quantitative analyses results that are in agreement with those using sulfur selective detectors. This versatile system can also perform a standard American Society for Testing and Materials benzene purity analysis at the same time the thiophene measurement is made.