Efficient Sample Workflow from Extraction to Analysis for Pesticides Using EPA 608/8081

Oral Presentation

Prepared by Z. Grosser, M. Ebitson, A. Cannon
Horizon Technology, Inc., 16 Northwestern Dr., Salem, NH, 03079, United States

Contact Information: zgrosser@horizontechinc.com; 603-386-3654


The analysis of pesticides continues to be an important measurement to monitor contamination in many matrices that might contribute to human exposure, such as water, soil and food stuffs. Pesticides in water, including drinking, wastewater, and groundwater, are the largest contributors, and hence, it is especially important to consider for a wide variety of current, banned and potential pesticides.

The goal is to perform these analyses with the most efficiency to minimize turnaround time and cost. The impact of two steps in the process will be evaluated in this work. The elimination of the solvent exchange step to replace dichloromethane (DCM) with hexane to be compatible with GC-ECD is time-consuming, but necessary because the best extraction efficiency for a liquid-liquid extract is obtained with DCM. Using a solid phase extraction disk provides the same or better extraction, and subsequently, hexane can be used directly to elute the analyte from the disk. The drying of extracts using a membrane system rather than sodium sulfate eliminates a number of problems and helps to smooth the overall sample preparation and delivery of a clean sample to the chromatographic system for analysis.

The overall impact of these two changes to the traditional workflow will be explored and the value to different sized laboratories measured.