High Throughput Semi Automated Solid Phase Extraction and Analysis of Waste Water Using EPA 8270D

Challenges and Opportunities for Solid Phase Extraction
Poster Presentation

Prepared by , R. Addink

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


ABSTRACT

Fully automated systems for Solid Phase Extraction (SPE) of semi-volatile organics (SVOCs) in aqueous samples using EPA method 8270D are now commercially available. To meet demands for a low cost method that requires less financial investment than automated systems, a simple semi - automated system which is fast and cheap while yielding high quality data was developed.

Traditionally involving 6 LLE shakes at both pH 2 and 12, plus heavy emulsions and low recoveries, manual extractions are time consuming and often result in poor results. By incorporating semi-automated SPE with multi-bed sorbents, samples can be extracted with a single pass procedure without emulsions, centrifuging and hours of manual labor. Using semi-automated SPE with multiple cartridges provides a solution for the SVOCs extraction process.

Method: Six 1L water samples were brought to pH~2, spiked with standards. Rinse bottles were filled with 35mL dichloromethane. ABN cartridges on top of coconut charcoals ones were conditioned with DCM, methanol and water. Samples were loaded under vacuum, dried for 1 min (nitrogen). ABN cartridges were removed, put on other side of system for collection, sample bottles were automatically rinsed with DCM (nitrogen). Rinses were loaded across ABN cartridges for collection (Fraction # 1). Cartridges were put back on top off coconut charcoals ones, conditioned with 50 mL 1% NaOH, dried for 1 min. The individual cartridges were eluted with DCM for collection (Fraction # 2). Fractions were dried over Na2SO4, reduced in volume with automated evaporation and spiked with internal standards. Analysis was done with low-res GC/MS.

Recoveries for the semi-automated SPE system were all well within the acceptance QC limits for waste water matrices. Analysis of additional analytes showed the application is also suitable for analytes beyond those with specified QC criteria by the method.