FTIR (Fourier Transform Infrared) Transmission Spectrometry for the Nondestructive Determination of Ammonium and Sulfate in Ambient Aerosols Collected on Teflon Filters

摘要

Fourier transform infrared transmission spectroscopy is used to analyze directly for sulfate and ammonium present in ambient aerosol particles deposited on Teflon filters. Integrated infrared peak areas for sulfate and ammonium are linearly related to x-ray fluorescence measurements for total sulfur. The detection limit, in terms of total sulfur, is 450 ng/cu.m. using samples volumes of 21.6 cu.m. The actual detection limit may be less since uncertainties of 5-8% occur in the x-ray fluorescence measurements and all sulfur may not be in the form of ammonium sulfate. In order to determine the influence of site-dependent variations in collected particles on the infrared measurement, samples from four widely different sites were analyzed.