Chemistry at level of individual aerosol particle using multivariate curve resolution of confocal Raman image.
Airborne particles with aerodynamic diameter in the 10-1 microm range have been collected in an industrial/urban zone by impaction and have been investigated by automated confocal Raman microspectrometry. The computer-microcontrolled XY scanning and Z focusing of Raman images provided many pixel Raman spectra which are characteristics of complex mixture at level of individual particle. The large heterogeneity was not resolved by the spatial resolution of the instrument which is limited by the optical diffraction. The severe spectral overlaps generated by heterogeneity were resolved by multivariate curve resolution (MCR) methods. The purity based method (SIMPLISMAX) was used to resolve both luminescence spectra and pure Raman spectra without prior information. The MCR-alternating least square (ALS) was used as a refined method of both spectra and spectral concentrations. The reconstructing Raman images of the respective spectral contribution supply a versatile potential to characterize the chemistry of atmospheric aerosols at the level of the individual particles.
Laboratoire de Spectrochimie Infrarouge et Raman, UMR-CNRS 8516, CERLA FR-CNRS 2416, University of Sciences and Technologies of Lille, Bât C5, Villeneuve d'Ascq Cedex F-59655, France. sophie.sobanska@univ-lille1.fr
Sophie
S
Sobanska
Guillaume
G
Falgayrac
Jacky
J
Laureyns
Claude
C
Brémard
D000393:Air Pollutants / Q000737:chemistry*; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D015591:Microspectrophotometry / Q000379:methods
D000393:Air Pollutants; D004391:Dust