Identification of nitrophenols in rain-water by high-performance liquid chromatography with photodiode array detection
Nitrophenols were extracted from rain-water with dichloromethane in two steps. Isocratic separation by high-performance liquid chromatography was achieved with methanol-phosphate buffer (40:60) at pH 3.25. A photodiode array detector was employed to detect the individual nitrophenols at their optimum wavelengths and to identify these compounds by comparison of their UV spectra with those of reference compounds. Depending on the individual compound and the extraction method, the recoveries ranged from 26 to 100% while the detection limit was 0.1-0.5 myg/l. 4-Nitrophenol, 2,4-dinitrophenol, 2,6-dimethyl-4-nitrophenol, 4,6-dinitro-2-methylphenol and most likely 3-methyl-4-nitrophenol were identified in rain-water.