||Use of Isopropanol to Distinguish H2SO4 from Particulate Sulfate on Filters.
Cheney, J. L. ;
Fortune, C. R. ;
Turlington, C. F. ;
||Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Sciences Research Lab. ;Northrop Services, Inc., Research Triangle Park, NC.
Solvent extraction ;
Sulfur oxides ;
Filtered particle testing ;
Chromatographic analysis ;
Materials recovery ;
Sulfuric acid ;
IPA(Anhydrous Isopropanol) extraction
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Potential interferences in the anhydrous isopropanol (a-IPA) extraction method for separating sulfuric acid from particulate sulfate on filters were investigated. The method involves separation and recovery of the acid with a-IPA, followed by aqueous extraction of the particulate. Analysis for sulfate in the separate fractions was performed by ion chromatography. The solubility of ammonium sulfate in a-IPA was measured and the effects of temperature and moisture content of the solvent on ammonium sulfate solubility were determined. Neither a small uptake of moisture by the a-IPA nor elevated temperatures up to 30 C had a significant effect on the solubility of ammonium sulfate in IPA. Ammonium sulfate was determined to be very highly insoluble in a-IPA and therefore, exposure of samples to any source of ammonia will result in low recoveries of sulfuric acid by the solvent recovery procedure.