FRACTIONATION OF POLAR ORGANIC EXTRACTS OF AIRBORNE PARTICULATE MATTER USING CYANOPROPYL-BONDED SILICA IN SOLID-PHASE EXTRACTION

A mg-scale fractionation method has been developed for polar organic matter in airborne particles. The method gives reproducibly good recoveries of mass while avoiding the use of water or salts. Cyanopropyl-bonded silica solid-phase extraction (SPE) columns were used to fractionate a mixture of standard compounds and acetone-soluble extracts from particles collected in Elizabeth, NJ, USA and from National Institute of Standards and Technology Standard Reference Material SRM 1649 (urban air particles). Critical factors proved to be reducing the polarity of the extract before its application to the column and pre-wetting the column with n-hexane. Ten fractions were eluted with solvent mixtures of increasing polarity, ranging from n-hexane to methanol. Blank-corrected mass recoveries were 95 and 98% for the Elizabeth, NJ, USA and SRM 1649 extracts, respectively.