ARS | Publication request: Headspace analysis of polar organic compounds in biological matrixes using solid phase microextraction (SPME)

Submitted to: Meeting Proceedings
Publication Type: Abstract
Publication Acceptance Date: September 3, 2008
Publication Date: N/A

Technical Abstract: Analysis of biological fluids and waste material is difficult and tedious given the sample matrix. A rapid automated method for the determination of volatile fatty acids and phenolic and indole compounds 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. Samples (1-5 ml) were centrifuged and pH (pH approximately 2) and salt (0-40% w/w) adjusted prior to incubation on the MPS. The MPS incubated sample 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, sample volume, and pH, while critical factors improving the robustness of the method included extraction times, pH, and salt content. The factors controlling speed of analysis included 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 external standards and verified by internal spiked standards.