GC/MS analysis of water-soluble organics in atmospheric aerosol: optimization of a solvent extraction procedure for simultaneous analysis of carboxylic acids and sugars.

The main goal of the present study was to develop a procedure for the simultaneous GC/MS analysis of a wide range of water-soluble organic compounds (WSOCs, mainly dicarboxylic acids and sugars) in atmospheric aerosol as chemical markers of atmospheric processes. The response surface methodology, including central composite design, was applied to systematically investigate and optimize the operating conditions of a solvent extraction method as the most widely used procedure for determining WSOCs in particulate matter (PM) samples. A solvent mixture of methanol/dichloromethane (90:10) and a volume of 10 ml were the optimum conditions that permit the simultaneous analysis of 30 target WSOCs, including dicarboxylic acids and sugars. Recoveries and limits of detection were determined for a standard mixture containing target analytes, and they varied from 79 to 103 % and 0.3 to 1 ng m(-3), respectively. The optimized procedure was used for the analysis of field PM filters and demonstrated its feasibility in detecting several important environmental WSOCs.