HIGH-SPEED GC ANALYSIS OF LOW-MOLECULAR-WEIGHT C-H AND C-H-CL COMPOUNDS WITH POROUS-LAYER OPEN-TUBULAR COLUMNS

Short lengths of porous-layer open-tubular (PLOT) columns operated at average carrier gas velocities of about 150 cm/s are used to separate relatively simple mixtures of C-H and C-H-Cl compounds in a few seconds. A high-speed inlet system is used to obtain injection bandwidths less than about 5 ms, and a high-speed electrometer is used to collect data. PLOT columns with stationary phases of Al2O3, porous polymers, and carbon are compared with respect to selectivities, retention stability, and general utility for the rapid separation of low molecular weight organic compounds. Porous polymer phases show good selectivity and good stability. Al2O3 phases show excellent selectivity, but retention-time drift, probably due to traces of water in the samples, can be significant. Carbon phases show poor selectivity for the samples considered.