Analysis of Persistent Organic Pollutants in Drinking Water with Semi-Automated Solid Phase Extraction

Challenges and Opportunities for Solid Phase Extraction
Poster Presentation

Prepared by T. Hall, R. Addink
Fluid Management Systems, 580 Pleasant St, Watertown, MA, 02472, United States

Contact Information: [email protected]; 617-393-2396


Continued interest in Persistent Organic Pollutants (POPs), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), biphenyls (PCBs), and Organochlorine Pesticides (OCPs) has led to a variety of automated systems for the Solid Phase Extraction (SPE) of various kinds of water samples, including drinking water. To meet demands for a lower cost method that requires less financial investment than the automated systems, we developed a simple semi - automated system which is faster and cheaper while yielding high quality data in accordance with EPA method 508, 1613 and 1668.

Six 1 L water samples were acidified to pH~2, spiked with 5-10mL methanol and 13C labeled standards. The sample bottles were attached to the SPE system and sample rinse bottles were filled with 25 mLs dichloromethane. C-18 cartridges were installed in each of the six positions.

The next steps were divided in two stages. Stage 1: cartridges conditioned under vacuum with dichloromethane, methanol and water (5 mLs each), followed by loading samples across cartridges, drying (nitrogen) and automated sample bottle rinse (dichloromethane). Stage 2: bottle rinses eluted across C-18 cartridges and Na2SO4 cartridges and eluent collected for analysis.

Collection tubes with Direct-to-Vial connections were put in an automated concentrator, pre-heated (15min, 50 °C), and heated in sensor-mode under 7-10 psi nitrogen which assured automatic shut-off at 1 mL. They were further reduced in volume (except OCPs) in a vial evaporator and spiked with recovery standards. Analyses were done on GC/FID and high res GC/MS.
Excellent 13C labeled recoveries were seen for tetra-CDD/Fs thru octa-CDD/Fs between 75-105%. For the WHO-12 and indicator PCBs the 13C recoveries were between 70-90%. For OCPs recoveries for ~ 22 analytes were 70-110%.
The semi-automated SPE system produces reliable and reproducible results for dioxins, furans and PCBs in drinking water. The system is cheaper than fully automated SPE equipment.