Tandem Mass Spectrometry (MS/MS) for Analysis of Substituted Polycyclic Aromatic Compounds in Extracts of Diesel Exhaust Particulates

摘要

The project developed tandem mass spectrometric techniques for the analysis of the polar fractions from the soluble organic fractions of NBS SRM No.1650 diesel exhaust particulates. Three subfractions, numbered Fractions 7 through 9, were used for the development. Instrumentation utilized was a Kratos MS-50 triple analyzer, which consists of a high resolution MS-I, a standard Kratos MS-50, and a low resolution MS-II, an electrostatic analyzer. Two modes of spectrometer scanning, acquisition of daughter ion spectra, and constant neutral loss (CNL) were explored. Two methods of sample ionization, Fast atom bombardment (FAB), and electron ionization (EI) were investigated. Negative ion chemical ionization (NICI) was subsequently investigated to improve specificity and sensitivity. The MS/MS spectra of 12 nitro-PAH standards were determined and a detection limit of 1 picogram of material was established.