Tuesday, November 14, 2006 - 10:00 AM

Automated Method for Analysis of 18 Odorants in Swine Manure.

Steven Trabue1, Kenwood Scoggin2, and Jon Schiller2. (1) 2150 Pammel Dr, DuPont Ag. Products, USDA-ARS, National Soil Tilth Laboratory, Ames, IA 50011, (2) USDA-ARS, "National Soil Tilth Laboratory, 215", "National Soil Tilth Laboratory, 215", Ames, IA 50011, United States of America

Air quality in rural communities is negatively impacted by waste products from animal production facilities.  Determining the types and levels of odorants in waste material is needed if proper odor abatement strategies are to be developed.  However, analysis of waste material is difficult and tedious given the sample matrix of animal waste.   A rapid automated method for the determination of 18 odorants in swine manure was developed using a multipurpose sampler (MPS) with solid phase microextraction (SPME) and GC-FID analysis.  The extraction conditions such as extraction mode (i.e., liquid or headspace), pH, salt addition, extraction temperature, sample volume, and extraction time were examined.  The MPS was used to control both the extraction temperature and extraction time.  Manure samples (1-10 mL) were centrifuged and pH (pH approximately 2) and salt (0-40% w/w) adjusted prior to incubation on the MPS.  The MPS incubated manure extracts (10-25 min) at elevated temperatures (25-100oC) and extracted time (0.5-180 min) prior to analysis by GC-FID.  Critical factors lowering the limit of quantitation included temperature of incubation, salt content, pH, and extract volume, while critical factors improving the robustness of the method include extraction times, pH, salt content.  The factors controlling speed of analysis include incubation time and initial GC column starting temperature.  Fiber degradation was strongly influenced by incubation temperature and final pH of manure.  Calibration of the SPME fiber was preformed by both external standards and standard addition given similar results.