Heated flow-cell for gas phase UV-visible detector in gas chromatography of polycyclic aromatic hydrocarbons

Summary A detection system for gas chromatography based on gas-phase, molecular absorption measurements is presented, in which the chromatographic column is directly joined to the spectrophotometer flow cell, without heated transfer lines. To maintain polyciclic aromatic hydrocarbons (PAHs) in the gas phase during detection an aluminium heater was constructed. A mixture of 13 PAHs was then separated and analyzed. Parameters affecting separation (temperature program and carrier gas flow) were studied and a program designed to modify the measurement wavelength during the chromatography. The analytical characteristics of each compound were calculated, obtaining detection limits 0.2–1.5 μg mL⁻. Given that some compounds overlaped, it was necessary to resolve their peaks mathematicaly. Finally, the method was applied to a certified synthetic mixture, with good results.