EPA 625: Base, Neutral, Acid Semi-volatiles in Municipal and Industrial Waste Water by Solid Phase Extraction

Oral Presentation

Prepared by T. Hall, P. Bassignani
Fluid Management Systems, 580 Pleasant Street, 1st Floor, Watertown, MA, 02038, United States


Contact Information: thall@fms-inc.com; 617-744-8467


ABSTRACT

Solid Phase Extraction has long been used for the analysis of semi-volatile organics in clean matrices. However, with waste water laboratories have predominately adhered to LLE (Liquid-Liquid Extraction) protocols. With new packing materials and better automated extraction systems difficult matrices are now routinely done with SPE. Manual techniques for EPA 625 extractions involve 6 LLE shakes at both pH 2 and 12, heavy emulsions, and low recoveries and are time consuming. With automated SPE with multi-bed sorbents, 625 samples can be extracted with a single pass procedure without emulsions, centrifuging and hours of manual labor. A Semi-Volatile System was used to handle multiple cartridges, and provide a fully automated solution for the semi-volatile EPA 625 extraction process.

1 L samples of DI water and ASTM synthetic waste water were prepared. Samples were acidified and spiked with relevant standard solutions (such as 8270 matrix spike). Coconut charcoal and mixed bed cartridges were used. These were pre-wetted/conditioned with dichloromethane, methanol and water. Samples were passed across both cartridges under vacuum and dried with nitrogen. Bottle rinse (DCM) was followed by loading across mixed bed cartridge, collection (Fraction 1), 10 mLs of DCM, reconditioning of mixed bed cartridge, 1% NaOH, drying, and elution with 30 mLs DCM (Fraction 2). Coconut charcoal cartridge was eluted with 30 mLs DCM added to Fraction 2. Passing through sodium sulfate was followed by evaporation in SuperVap Concentrator under nitrogen.

Recoveries of PAHs and pesticides in synthetic waste water were 55-110%. Additional method 625 chemicals yielded between 30-100%.