Determination of Phenol Pollutants in Water at Trace Levels: Extraction by a Reversible Graphitized Carbon Black Cartridge

Abstract

Abstract A method for determining the 11 phenols designated as priority pollutants by the U.S. Environmental Protection Agency at the parts-per-trillion level in water sampled from the environment is described. Drinking (2 L), ground (1.5 L), and river (0.5 L) water samples are preconcentrated by passing them through a 1 g graphitized carbon black (GCB) reversible cartridge at a flow rate of approximately 70 mL/min. After the GCB cartridge is washed with 1.5 mL methanol to eliminate water, the cartridge is reversed and then back-flushed with an acidic CH2Cl2-CH3OH mixture for eluting phenols. After partial solvent removal, the sample is subjected to reversed-phase liquid chromatography with UV detection by either a conventional or a diode-array detector. Recoveries of phenols added to 2 L of drinking water at levels between 0.05 and 4 μg/L were higher than 90%. Compared with an oc-tadecyl bonded silica (C18) cartridge, the GCB cartridge had a far better extraction efficiency for the more highly water-soluble phenols. The extent to which the presence of fulvic acids in water affected the recovery of the phenols considered was investigated.