During the optimization of the chromatographic method, the
organic solvents most commonly used for PAH metabolite
determination were evaluated. A combination of acetonitrile
with water29,31 or methanol with water19,32 is reported by most
authors, and both of these combinations were tried. In a
preliminary study, an isocratic elution system, consisting of
methanol or acetonitrile and water (95:5), was attempted