Influence of collecting substrate on the Raman imaging of micron-sized particles.

ABSTRACT

The influence of six common substrates on the Raman imaging of micron-sized inorganic aerosol particles was examined. Laboratory-generated single-component particles of calcite (CaCO3) and mixed particles of calcite (CaCO3), nitratine (NaNO3), hematite (Fe2O3) and anglesite (PbSO4) were deposited by cascade impaction on Ag, In, Si, SiO2, microscope slide and TEM-grid substrates. The spectral contribution of substrates to Raman images of the deposited particles was evaluated by Multivariate Curve Resolution. The shape and intensity of the substrate spectra affect the effectiveness capability of the spectral deconvolution. The substrates were characterized and compared with respect to their effect on the reconstruction of Raman images of aerosol particles. The TEM-grid substrate yielded spatially stable sample measurements with a homogeneous spectral contribution, satisfactory Raman map reconstruction and the potential for application in other techniques (e.g., SEM-EDX).