Optimization of parameters affecting the recovery in the analysis of polycyclic aromatic hydrocarbons in natural waters by HPLC-fluorescence.

Abstract

To improve the recovery percentages in the analysis of PAH (polycyclic aromatic hydrocarbons) in natural waters, parameters such as standard stability, filtration, storage time and matrix effect were optimized for five PAH by HPLC-FD. For aqueous standards, with the addition of 10% acetonitrile, good linearity was found for naphthalene, acenaphthene, anthracene, pyrene, and chrysene curves up to the second day of standards preparation. In filtration, the best results were obtained using the AP10 and Nylon filters with 10% acetonitrile, with recovery ranges of 98-72% and 93-56%, respectively. In contrast, lower values were obtained with cellulose filters in a polyethylene holder without the addition of 10% acetonitrile with recoveries of 52-0%. A 23 factorial design established, for natural water, that the most important factors were: storage time for naphthalene and acenaphthene, with area losses at 48 hours and the use of organic solvent for anthracene, pyrene and chrysene, with area gain for 20 % acetonitrile. For liquid-liquid extraction in standards, recoveries of 62-45% were found in aqueous matrix without acetonitrile and 98-35% with 20% acetonitrile + 2.5% NaCl, at 24 hours of preparation.