HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY RETENTION INDEX AND DETECTION OF NITRATED POLYCYCLIC AROMATIC-HYDROCARBONS

Based on reversed-phase isocratic experiments and gradient optimization modeling, acetonitrile was found to provide optimum separation of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs). A 31-min linear gradient between 24% and 80% acetonitrile in water at 35-degrees-C and 0.5 ml/min flow-rate was established. Nitro-PAH retention indices, I, were measured under these conditions. It was found that retention index values varied with changing column temperature and/or mobile phase compositions. Diode-array, fluorescence (FD) and chemiluminescence (CD) detection were studied for nitro-PAHs. Diode-array detection responded linearly with detection limits between 2 and 12 ng/compound injected. In addition, dual-wavelength UV absorbance ratio (A230/A254, A330/A254 and A230/A330) measurements at these wavelength pairs were reported. Fluorescence and chemiluminescence provided increased selectivity and sensitivity. Four orders of magnitude linear range were found for both detection methods with detection limits between 10 and 15 pg and 50 pg (on an NO2/compound mole basis), respectively.