A SIMPLE DETECTION SYSTEM FOR GAS-CHROMATOGRAPHY BASED ON MOLECULAR ABSORPTION SPECTROMETRY IN THE GAS-PHASE

A simple and inexpensive detection system for gas chromatography, base d on gas-phase, molecular absorption measurements, is presented in whi ch the chromatographic column is directly joined to the spectrophotome ter flow cell, without heated transfer lines. A mixture of eight benze ne compounds (including methyl, halogen and nitrogen derivatives) were separated and analyzed. Parameters affecting separation (temperature program and carrier gas flow) and measurement quality (wavelength and integration time) were studied and a measurement program designed to m odify the wavelength during chromatography. The analytical characteris tics of each compound were calculated, obtaining detection limits rang ing from 0.5 to 9 mu g mL(-1). Finally, the method was applied to seve ral synthetic mixtures, with good results.