High Throughput Solid Phase Extraction, Cleanup and Concentration of Organochlorine Pesticides in Waste Water Using EPA Method 608.3

New Organic Monitoring Techniques
Oral Presentation

Prepared by R. Addink, T. Hall
Fluid Management Systems, 900 Technology Park Dr, Billerica, MA, 01821, United States


Contact Information: raddink@fms-inc.com; 617-393-2396

ABSTRACT

Organochlorine Pesticides gained wide spread attention in the latter part of the 20th century, ultimately leading to their ban; they remain with us as a legacy contaminant. In waste water samples, OCPs are monitored using EPA method 608.3.

Use of Solid Phase Extraction (SPE) can increase extraction efficiency and reduce solvent usage. By implementing a system with dual cartridge functionality, an in-line Florisil cartridge can be added to perform automated extract cleanup during the elution step.

Twelve samples (1L water each) were prepared, acidified with HCl to pH < 2, and spiked with 608.3 standards. Sample bottles were put in place and rinse bottles filled with 40 mL 10% acetone/hexane. C-18 cartridges were installed in each of the twelve positions. The vacuum was turned on and the cartridges conditioned with acetone (2 min soak) and water. Samples were then loaded across the cartridges at ~ 12 inch Hg and dried (10 min). C-18 cartridges were removed and Hydromatrix cartridges on top of Florisil cartridges were put in place and conditioned with 10% acetone/hexane. The Hydromatrix/Florisil cartridge assembly was put on top of C-18 cartridges and sample bottles were automatically rinsed from rinse bottles with 40 mL 10% acetone/hexane. Bottles rinses were then eluted across the cartridges and collected in Direct-to-GC-Vial collection vessels for analysis.

The collection tubes were put in an automated concentrator, pre-heated for 15 min at 50 °C, and heated in sensor-mode under 7-10 psi nitrogen which assured automatic shut-off at 1 mL. Analysis was done with micro-ECD.

Excellent recoveries were seen for various compound classes in the method (e.g., organochlorine pesticides, toxaphenes, Aroclor-1242) between 75-110%. Total run time is about 80 min including 50 min of sample loading. The system is inexpensive and produces fast and reliable data. Twelve samples can be run in parallel.