Determination of SCFAs in Food Wastewater using HS-SPME

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Research article

Journal of the Korean Society for Environmental Analysis 2013;16(2):105-114.

Abstract

In this study, we identified short chain volatile fatty acids (SCFAs) in wastewater using headspace solidphase micro-extraction (HS-SPME) coupled to gas chromatography (GC) analysis. Among three different SPME coatings, (i.e., 85 μm Polyacrylate (PA), 75 μm Carboxen/Polydimethylsiloxane (CAR/PDMS) and 30/50 μm Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS)), 75 μm CAR/PDMS fiber was chosen since it showed the most successful extraction of Acetic acid (AA) and Propionic acid (PA). The optimal extraction and quantification conditions for the fiber such as extraction time and temperature, desorption time and temperature, agitation speed, sample volume and headspace/aqueous ratio also have been determined. The resulting calibration curve for each analyte showed good linearity (R2: 0.997~0.999) over the range from several ppbv to ppmv except for AA (R2: 0.986), low method detection limit, and good reproducibility in the quantification of the SCFAs. The developed method was applied to analyze SCFAs in extracted liquid from food wastes. The results obtained from the developed method were comparable to those from the method using GC with direct liquid injection. However, the distillation method underestimated the total SCFAs (C2~C6 acids)especially when C2~C6 acids were at high levels.

Key Words: SCFAs, SPME, Food wastewater, CAR/PDMS fiber, The optimal analysis conditions