Analysis of semivolatile organic compounds in atmospheric aerosols by direct sample introduction thermal desorption GC/MS

A technique for identifying trace amounts of semivolatile organic compounds in atmospheric aerosols and in the NIST Urban Dust standard (SRM1649a) is presented. The technique is based on direct sample introduction (DSI) of sm all samples followed by thermal desorption in a conventional GC injector. T he method enables injection of both solid and liquid samples. Validation of the method, including quantitative determination of EPA-targeted polycycli c aromatic hydrocarbons (PAHs), as well as the reproducibility and recovery efficiency tests are presented. The advantages of using aluminum foil as s ampling filter are also discussed. Determination of different classes of co mpounds such as quinolines, methylquinoline isomers, PAHs, and n-monocarbox ylic acids in the ambient size-segregated aerosol sample is also performed. The method was directly applied to the determination of C-6-C-16 n-monocar boxylic acids, eliminating the need for a complex sample preparation proced ure. The small quantities needed for the analysis as well as the lack of co mplicated sample preparation steps enable fast characterization of semivola tile organic species present in time-resolved or size-segregated aerosol sa mples. Thus, this method can potentially be employed for air quality monito ring and field measurements as well as for fast screening of the organic co ntent of ambient particles.