title: Automated chemical analysis of internally mixed aerosol particles using X-ray spectromicroscopy at the carbon K-edge.
abstract: We have developed an automated data analysis method for atmospheric particles using scanning transmission X-ray microscopy coupled with near edge X-ray fine structure spectroscopy (STXM/NEXAFS). This method is applied to complex internally mixed submicrometer particles containing organic and inorganic material. Several algorithms were developed to exploit NEXAFS spectral features in the energy range from 278 to 320 eV for quantitative mapping of the spatial distribution of elemental carbon, organic carbon, potassium, and noncarbonaceous elements in particles of mixed composition. This energy range encompasses the carbon K-edge and potassium L2 and L3 edges. STXM/NEXAFS maps of different chemical components were complemented with a subsequent analysis using elemental maps obtained by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX). We demonstrate the application of the automated mapping algorithms for data analysis and the statistical classification of particles.
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720-8226, USA.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Moffet
authors.forename: Tobias
authors.initials: T
authors.lastname: Henn
authors.forename: Alexander
authors.initials: A
authors.lastname: Laskin
authors.forename: Mary K
authors.initials: MK
authors.lastname: Gilles
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000465:Algorithms; D001272:Atmosphere; D001331:Automation; D002244:Carbon / Q000737:chemistry*; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*; D010316:Particle Size; D011188:Potassium / Q000737:chemistry; D025341:Principal Component Analysis; D013816:Thermodynamics
chemical_list: D000336:Aerosols; D002244:Carbon; D011188:Potassium