Analysis of Perfluorinated Compounds in Wastewater Using Automated Solid Phase Extraction

Oral Presentation

Prepared by R. Addink, T. Hall
Toxic Report LLC, 580 Pleasant St, Watertown, MA, 02472, United States


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


ABSTRACT

Perfluoralkylated compounds contain a perfluorinated or polyfluorinated carbon chain moiety such as F(CF2)n- or F(CF2)n-(C2H4)n. In recent years there has been increasing concern over the levels of these chemicals, (e.g., PFOS (perfluorosulfonate), and PFOA (perfluoro-octanoicacid)) in the global environment because of their fate and possible adverse effects. PFOS are subject to varying but increasing levels of control in various countries. This study demonstrates the first automated solid phase extraction system made specifically for PFC extraction and concentration. Primarily effective at reducing background contamination, extraction and concentration of aqueous samples takes less than two hours. The application described here is especially aimed at waste water analysis.

500 mL water samples were spiked with 25 uL of a 1 ug/mL PFC standard solution. Samples were then loaded onto the PFC SPE system and passed across an FMS PFC 1 g cartridge under -12 psi vacuum. After loading, the bottle was rinsed with 25 mL of water and loaded onto the cartridge under negative pressure. The cartridges were dried with nitrogen until no residual water was present, and subsequently eluted with methanol. The extracts were concentrated to 500 uL, after which internal standard was added. Samples were diluted to a final volume of 1 mL for LC/MS analysis.

A number of perfluorinated compounds were spiked in water (50 ng/L). Some of the results were: PFHxA 61% recovered, background from system (0.068 ng/L); PFHxS 77% (0.06 ng/L); PFOA 88% (0.214 ng/L); PFNA 74% (0.062 ng/L); PFOS 72% (0.048 ng/L); PFDA 84% (0.054 ng/L); PFUdA 65%; PFDoA 57% (0.011 ng/L). The automated Solid Phase Extraction System for PFCs gives good recoveries and very low background. Set up and cleanup is easy and allows for unattended extraction. The LC/MS system used had predictable background PFC easily subtracted to give accurate results for waste water analysis.