INVESTIGATION INTO THE FACTORS AFFECTING PERFORMANCE IN THE DETERMINATION OF POLYCYCLIC AROMATIC-HYDROCARBONS USING CAPILLARY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY WITH SPLITLESS INJECTION

The importance of solvent choice and temperature program for the separation and quantification of sixteen polycyclic aromatic hydrocarbons (PAHs), considered as priority pollutants, was investigated. For the eight late-eluting PAHs, higher boiling solvents, such as toluene and the xylenes, gave enhanced signals that were between 1 and 100 times greater than those from splitless injections in solvents such as dichloromethane, hexane, acetonitrile, benzene and isooctane. The results indicate that the greatest enhancement can be found by choosing a proper solvent for a specific range of PAHs coupled with an appropriate initial column temperature. Further studies of other parameters were accomplished with toluene as solvent. Simplex optimization of the injection temperature and the initial column temperature gave 260 and 120°C, respectively, as the optima. These optimum conditions also improved the peak shape and resolution. The dependence of the initial column temperature on solvent is discussed with respect of sensitivity and resolution. Detection limits (signal-to-noise ratio=3) range from 2.4 pg for naphthalene to 86 pg for benzo[ghi]perylene. Relative standard deviations of seven replicate determinations of a 3-ng injection ranged from 2.2 to 10.5% when measured by peak area and from 3.9 to 11.0% when measured by peak height. The studies further illustrate that the sensitivity of late-eluting PAHs can be further improved when xylenes are used as solvents. © 1990.