<p>Exposure to
combustion generated aerosols such as PM from residential woodburning, forest
fires, cigarette smoke, and traffic emission have been linked to adverse health
outcomes. It is important to assess the chemical composition of PM to examine personal
exposure. Excitation-emission matrix (EEM) spectroscopy has been shown as a sensitive
and cost-effective technique for evaluation of combustion PM composition and as
a source apportionment tool. However, EEM measurements are hindered by a solvent
extraction step and a need for benchtop instrumentation. Here, we present a methodology
that eliminates this labor-intensive sample preparation and allows to automate
and miniaturize the detection platform. A miniature electrostatic collector
deposits PM sample onto transparent polydimethylsiloxane (PDMS) coated substrate,
where PAH components are extracted into solid-phase (SP) solvent and analyzed
using EEM spectroscopy in-situ. We evaluated external and internal excitation
schemes to optimized signal to noise ratio. Analysis of woodsmoke and cigarette
smoke samples showed good agreement with liquid extraction EEM spectra. Internal
excitation is hindered by fluorescent interference from PDMS at λ<250nm. The external excitation EEM spectra are
dependent on the incident angle; ranges of 30-40⁰ and 55-65⁰ showed the best results. The proposed SP-EEM technique can be used for development of
miniaturized sensors for chemical analysis of combustion generated PM. </p>
Identification of resistance in Escherichia coli and Klebsiella pneumoniae using excitation-emission matrix fluorescence spectroscopy and multivariate analysis
