ARS | Publication request: A COMPARISON OF SOLID PHASE MICROEXTRACTION AND STIR BAR SORBTIVE EXTRACTION FOR THE QUANTIFICATION OF MALODORS IN WASTEWATER

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2006
Publication Date: November 1, 2006
Citation: Loughrin, J.H. 2006. A comparison of solid phase microextraction and stir bar sorbtive extraction for the quantification of malodors in wastewater. Journal of Agricultural and Food Chemistry.

Interpretive Summary: Malodors in wastewater from animal rearing facilities are due to the presence of characteristic compounds with high water solubility. Often, these compounds are measured by solid phase microextraction (SPME), a technique in with a polymer coated fiber is extended into a sample and adsorbed compounds subsequently measured by gas chromatography. The efficiency and reproducibility of three types of SPME fibers (carboxen-PDMS, polyacrylate and PDMS) as well as polymer-coated stir bars for the measurement of some of these compounds in water was compared. In initial experiments, the SPME fibers and stir bars were exposed to a standard water solution containing a mixture of 18 compounds with a range of water solubility. The polyacrylate SPME fibers and PDMS-coated stir bars, having found to possess the best combination of extraction efficiency and reproducibility of measurement, were compared for the extraction of a high strength swine wastewater. Ten compounds, which are known contributors to malodors in wastewater, were quantified by both methods of extraction. For most compounds, greater levels were estimated by the PDMS-coated stir bars than by SPME and measurement reproducibility was also greater. For both methods of extraction, there was greater variation in the measurement of volatile fatty acids than there was for other types of compounds.

Technical Abstract: Malodors in wastewater from animal rearing facilities are due to the presence of characteristic polar compounds. The efficiency and reproducibility of three SPME fibers (carboxen-PDMS, polyacrylate and PDMS) as well as PDMS-coated stir bars for the measurement of some of these compounds in the liquid phase was compared. In initial experiments, the SPME fibers and stir bars were exposed to a standard water solution containing a mixture of 18 compounds with a range of octanol-water partition coefficients. The polyacrylate SPME fibers and PDMS-coated stir bars, having found to possess the best combination of extraction efficiency and reproducibility of measurement, were compared for the extraction of a high strength swine wastewater. Ten compounds, which are known contributors to malodors in wastewater, were quantified by both methods of extraction. For most compounds, greater levels were estimated by the PDMS-coated stir bars than by SPME and measurement reproducibility was also greater. For both methods of extraction, there was greater variation in the measurement of volatile fatty acids than there was for aromatics.