Journal of Chromatography A, 1101 (2006) 179–184 Analysis of phenols in water by high-performance liquid chromatography using coumarin-6-sulfonyl chloride as a fluorogenic precolumn label Fakhr Eldin O. Suliman ∗ , Suad S. Al-Kindi, Salma M.Z. Al-Kindy, Haider A.J. Al-Lawati Sultan Qaboos University, College of Science, Box 36, Department of Chemistry, Al-Khod 123, Oman Received 23 June 2005; received in revised form 25 September 2005; accepted 29 September 2005 Available online 2 November 2005 Abstract A simple, sensitive and rapid reversed-phase high-performance liquid chromatography (RP-HPLC) method is proposed for the analysis of some environmentally important phenols in water. The use of coumarin-6-sulphonyl chloride (C6SCl) as a fluorescence-labeling reagent has been investigated. The compound reacts with phenols within 20 min under mild conditions (ambient temperature, pH 9.0) to give sulphonates that can be separated by RP-HPLC employing fluorescence detection at λ ex = 360 and λ em = 460 nm. The optimum conditions for fluorescence, derivatization and chromatographic separation have been established and detection limits in the range 0.1–0.9 gl -1 were obtained for the studied compounds. The calibration curves were linear for the range 6–200 gl -1 for phenol, 3–200 gl -1 for 2-chlorophenol, 4-chlorophenol and 2,3,5-trichlorophenol and for the range of 3–100 gl -1 for 2,3-dichlorophenol and 3,5-dichlorophenol. The practical applicability of the method to environmental samples was demonstrated by analyzing drinking and industrial water samples spiked with the phenolic compounds. © 2005 Elsevier B.V. All rights reserved. Keywords: Phenols; HPLC; Fluorescence; Cuomarin-6-sulfonyl chloride 1. Introduction There is a growing concern regarding the quality of water especially in regions suffering from water shortage. Among various water pollutants, phenol and substituted phenols are con- sidered toxic and may cause various problems [1]. Phenol is used to prepare aspirin and dyes, and most of it is converted to pheno- lic resins used in adhesives and plastics [2,3]. They are used as antiseptics, in pharmaceutical products, cosmetics and in a wide range of agricultural and industrial processes [4–7]. Chlorophe- nols, such as 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4- DCP) and 2,4,6-trichlorophenol (2,4,6-TCP), are known to be present in water following disinfection processes [8]. They find their way to rivers water, ground water, wastewater, sediments and soil as a result of their wide use. Generally, toxic phenols include chloro-, bromo-, nitro-, and alkylphenols. Some of these compounds are either known or suspected endocrine disruptors or carcinogens [9–11]. They are lipophilic in nature and are readily capable of interfering with the ∗ Corresponding author. E-mail address: fsuliman@squ.edu.om (F.E.O. Suliman). cell respiration system [12]. The carcinogenicity of chlorophe- nols is still controversial; nevertheless a significant increase in soft-tissue sarcomas and non-Hodgkin’s lymphomas has been linked to the presence of chlorophenols [13]. Owing to their toxicity, presence in the environment and their unpleasant organoleptic properties, phenols have been added to the priority lists of pollutants by the United States Environmental Protection Agency (EPA), and by the European Union (EU) [14–16]. The standard permissible level of total phenols is stated to be 0.5 gl -1 in drinking water, however, concentration of individual phenols must not exceed 0.1 gl -1 . A great deal of emphasis is placed on the development of effective, sensitive and reliable analytical methods with an improved recovery for monitoring trace levels of various phe- nols in water. This is envisaged by the rapidly growing concern about the quality of water, and the toxicity brought about by a number of contaminants including phenols. The early most popular methods for the determination of phenols are based on the reaction with 4-aminoantipyrine (4-AAP) in alkaline media [17,18]. In addition various methods for the assay of phenols have been reported employing gas chromatography, liquid chro- matography and capillary electrophoresis with various modes of detection, such as fluorimetry, spectrometry, chemilumines- 0021-9673/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2005.09.094