The determination of phenols is important in many areas, such as the characterization of hazardous waste products and the analysis of coal gasification by-products and the analysis of coal gasification by-product waters. Ultraviolet spectrometric phenolate anion measurement is a simple and reliable technique for the selective determination of phenol concentrations in water. For most common phenols, the difference in absorptivity at 291 nm caused by raising the pH from 7 to 12 and converting unionized phenols to phenolate anions provides an accurate measure of phenol concentrations despite variable sample compositions. This technique may be applied directly to aqueous samples or to other samples after extraction of phenols with a solvent.