Indentification and quantification of mono-, di- and trihydroxybenzenes (phenols) at trace concentrations in seawater by aqueous acetylation and gas chromatographic—mass spectrometric analysis

Abstract

A method is described that uses aqueous acetylation with acetic anhydride, solid-phase extraction (SPE) and concentration, and gas chromatographic—mass spectrometric (GC-MS) analysis to identify and quantify mono-, di- and trihydroxybenzenes (phenols) at low concentrations in marine and waste waters. Phenolic compounds in water samples were buffered with NaHCO 3 and directly acetylated with acetic anhydride. Phenol acetates were then extracted using C 18 SPE columns. The columns were eluted and the phenol acetates concentrated and analyzed by GC-MS. Detection of phenols in the ng 1 −1 concentration range can be obtained with 500 ml of sample. A large volume extraction setup is described from which detection limits in the upper pg 1 −1 range may be obtained. The method was applicable to a wide range of phenolic compounds but was not suitable for nitrophenols. Water samples from several coastal environments and wastewater treatment facilities were analyzed for phenols using this method. Phenol, cresols and catechols were the most common phenolic compounds identified. Concentrations ranged from 2.5 to 370 ng 1 −1 for these phenols in seawater sampled in San Diego Bay, in the vicinity of White's Point outfall off San Pedro (Los Angeles area) and outfalls off the Northern coast of California near Eureka.