A simple and straightforward procedure for monitoring phenol compounds in waters by using UV solid phase transduction integrated in a continuous flow system

A novel and sensitive flow-through method with solid phase UV spectrophotometric transduction is proposed for the direct determination of phenols: phenol, 1-naphthol, 2-naphthol, 3,4-dimethylphenol and 2,4-dichlorophenol were used as test phenol compounds. The device consists of a monochannel system using Sephadex QAE A-25 resin as packing material of the detection microzone placed inside a flow-through cell on which phenols are temporarily retained. Intrinsic absorbances are monitored at 237 nm for phenol, 242 nm for 2-naphthol and 3,4-dimethylphenol, and 247 nm for 1-naphthol and 2,4-dichlorophenol. The sample is transported by a alkaline carrier solution which acts as desorbing the solution itself. The determination of phenols was carried out for 40 and 600 muL of sample volume. The sensitivity is higher by a factor of 10 than that provided by a conventional flow injection analysis method. The detection limits were found to be close to 1 ng mL(-1) in some cases (using 600 muL of sample volume). The relative standard deviations (n = 10) ranged between 1.5 and 3.2% (40 muL) and 1.1 and 2.2% (600 muL). The proposed method has shown good results in its application to waters, making this method suitable for phenol monitoring.