Determination of PAHs: a practical example of validation and uncertainty assessment.

The objective of this study was to present a reliable and practical example of method validation and uncertainty assessment with an analytical method for the determination of polycyclic aromatic hydrocarbons (PAHs) in urban dust. The method was gas chromatography-mass spectrometry in combination with isotope dilution principle to achieve better accuracy for the results. The method performance parameters for five PAHs were determined (phenanthrene, fluoranthene, benzo[a]anthracene, benzo[a]pyrene and benzo[ghi]perylene); this method was used in the key comparison of CCQM-K50b for PAHs in particulate matter. The limits of detection and quantification were lower than 0.075 and 0.250 mu g/g, respectively. The linear correlation coefficients were greater than 0.99. The major uncertainty contributions resulted from the accuracy of each analyzed PAH and the repeatability of the process. Certified reference material (National Institute of Standards and Technology SRM 1649a, urban dust) was used to determine the accuracy and precision of the method. The obtained results were satisfactory and agreed with all evaluated performance parameters.