Ultrasound-assisted derivatization of phenolic compounds in spiked water samples before pervaporation, gas chromatographic separation, and flame ionization detection

A fully automated method, based on continuous ultrasound-assisted derivatization coupled with pervaporation before gas chromatographic separation and flame ionization detection, has been developed for the determination of phenol and cresols in water Spiked wafer samples were doped with acetic anhydride and dipotassium hydrogen phosphate, before introduction into the flow system, to achieve catalytic acetylation of the target compounds. A multi-variate study was performed to optimize the main factors affecting the derivatization process. The correlation coefficients, r of the calibration plots obtained were better than 0.999 for cresols and better than 0.99 for phenol. Detection limits were 0.02 mug mL(-1) for phenol, o-cresol, and p-cresol, and 0.05 mug mL(-1) for m-cresol. Reproducibility and repeatability, expressed as relative standard deviation, ranged from 2.0-3.9% and from 1.0-3.5%, respectively.