Analysis of Polychlorinated Dibenzo-p-dioxins, Furans and Biphenyls in Drinking Water with Semi-Automated Solid Phase Extraction Using EPA Method 1613

Challenges and Opportunities for Solid Phase Extraction
Oral Presentation

Prepared by

Contact Information: ruudaddink@toxicreports.com; 617-393-1713


ABSTRACT

Continued interest in Persistent Organic Pollutants (POPs), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and biphenyls (PCBs), 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 1613 method.

Six 1 L water samples were acidified to pH ~2, spiked with 5-10 mL methanol and with 13C labeled PCDD/F and PCB 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 the cartridges, drying (nitrogen) and automated sample bottle rinse (dichloromethane). Stage 2: bottle rinses eluted across the C-18 cartridges and Na2SO4 cartridges and the eluent collected for analysis.

Collection tubes with Direct-to-Vial connections were put in an automated concentrator, pre-heated for 15 minutes at 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 further in a vial evaporator and spiked with recovery standards. Analysis was done on a 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%.

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.