Comparative study for determination of some polycyclic aromatic hydrocarbons ‘PAHs’ by a new spectrophotometric method and multivariate calibration coupled with dispersive liquid–liquid extraction

• A new Extended derivative ratio method was developed and compared to PLS.
• A modification of dispersive liquid–liquid microextraction is proposed.
• This simple extraction technique is coupled to spectrophotometry.
• Five polycyclic aromatic hydrocarbons were determined in aqueous samples.

A modified dispersive liquid–liquid extraction (DLLE) procedure coupled with spectrophotometric techniques was adopted for simultaneous determination of naphthalene, anthracene, benzo(a)pyrene, alpha-naphthol and beta-naphthol in water samples. Two different methods were used, partial least-squares (PLS) method and a new derivative ratio method, namely extended derivative ratio (EDR).A PLS-2 model was established for simultaneous determination of the studied pollutants in methanol, by using twenty mixtures as calibration set and five mixtures as validation set. Also, in methanol a novel (EDR) method was developed for determination of the studied pollutants, where each component in the mixture of the five PAHs was determined by using a mixture of the other four components as divisor.Chemometric and EDR methods could be also adopted for determination of the studied PAH in water samples after transferring them from aqueous medium to the organic one by utilizing dispersive liquid–liquid extraction technique, where different parameters were investigated using a full factorial design.Both methods were compared and the proposed method was validated according to ICH guidelines and successfully applied to determine these PAHs simultaneously in spiked water samples, where satisfactory results were obtained. All the results obtained agreed with those of published methods, where no significant difference was observed.

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