Chlorophenols in tap water from wells and surface sources in Rio de Janeiro, Brazil: method validation and analysis

two analytical methods were validated for determination of trichlorophenols, tetrachlorophenols and pentachlorophenol in drinking water. limits of quantification were at least ten times lower than maximum permissible levels set by the brazilian legislation, which are 200 ng ml-1 for 2,4,6-trichlorophenol and 9 ng ml-1 for pentachlorophenol. chlorophenol levels were determined in tap water collected in the municipality of rio de janeiro. 2,4,6-trichlorophenol residues were detected in 36% of the samples, varying from 0.008 to 0.238 ng ml-1. all other analytes were below the limit of quantification. the validated methods showed to be suitable for application in routine quality control.