A method for the analysis of polycyclic aromatic hydrocarbons (PAHs) contained in complex environmental samples such as airborne particulate matter is presented, which is based on computations with n-successive derivative UV spectra. The algorithm can be applied to a direct extract of the sample with a single solvent such as cyclohexane. The UV spectrum of a sample (220-400 nm) is used to build a vector containing its 2nd-5th derivatives. This is multiple regressed against similar vectors containing the corresponding derivatives of the unit molar UV spectra of the target PAHs, and several noise signals built by multiplication of the analyte spectrum with several random noise vectors. The PAHs which are positively selected in this step are used for a second multiple regressive filter fitting all possible candidates into a single Beer's law model. A third filter, based on sensitivity analysis, selects the best significant components of the sample system. The present version of the algorithm has been tested with extracts of standard mixtures and extracts of SRM 1649 Urban Dust Organics (National Bureau of Standards). The results obtained are comparable in accuracy and precision to those obtained by chromatographic or direct extraction techniques. A considerable simplification of the extraction procedure and reduction of analysis costs and time are attained, which makes it a valuable tool as a secondary standard method for routine monitoring and systematic surveillance. The algorithm is coded in FORTRAN Microsoft for use in DOS 4.0 or higher AP personal computers.
