Spectrophotometric determination of phenols in water samples by the GHPSAM method

The generalized H-point standard-additions method (GHPSAM) is proposed in order to obtain the phenol concentration in water samples when the matrix is completely unknown. The procedure involves solid-phase extraction in BondElut PPL cartridges and data handling of the UV-visible spectrophotometry measurements. The spectral regions where the unknown interferent behaviour can be considered as linear are found and the analyte concentration free from bias error is estimated. The percentages of recovery of phenols in spiked samples were similar to those obtained by HPLC. Cresols or chlorophenols can be also determined in real samples by this method. The concentration range tested was 0.075 - 12.5 mg L-1 and the limits of detection found were in the 2.4 - 5.4 mug L-1 range. The method has been applied to real harbour water samples. The results obtained are compared to those provided by HPLC.