Emerald Group Publishing Limited
Copyright © 2000, MCB UP Limited
Analysis of polycyclic aromatic hydrocarbons
Keywords Spectral analysis, Hydrocarbons, Spectral analysis
Applicant: Greenvision Systems Ltd (IL)
Patent number: US5880830
Publication date: 9 March 1999
Title: Spectral imaging method for on-line analysis of polycyclic aromatic hydrocarbons in aerosols
The invention describes a method for on-line analysis of polycyclic aromatic hydrocarbons (PAH) in aerosols. The aerosols are collected on non-fluorescing filter paper, excited to fluorescence and imaged spectrally. The images are compared with spectra in a database to determine and quantify the PAH species present The scope of the invention is broader than fluorescence, and includes excitation analysis of particulate matter generally. According to the present invention there is provided a method for analysing particles for chemical components, comprising the steps of:
providing a database of emission spectra of the chemical components;
exciting said particles to emit emitted light;
acquiring a plurality of two dimensional images of said emitted light, each being acquired at a certain wavelength, including a plurality of pixels, each pixel having a location in the image, and having an intensity;
for a set of pixels sharing a common location: comparing the intensities, as a function of wavelength, to the emission spectra, thereby identifying the chemical components of the location.
The description in the patent concentrates on the use of the invention for the analysis of PAH in aerosols. Therefore, the emission spectra are fluorescence spectra and/or phosphorescence spectra, the emitted light is fluorescence and/or phosphorescence, and the emission is excited by incident ultraviolet light. Nevertheless, the scope of the invention includes all emission spectra that are useful in chemical analysis, including phosphorescence, Ramar and infrared spectra: and that the scope includes a variety of ways of exciting the particles to emit light, including incident light in other regions of the electromagnetic spectrum, for example, visible light and infrared light, and simply heating the particles.