Comprehensive Screening of Per- and Polyfluoroalkyl Substances (PFAS) in Food Contact Materials: Utilizing Combustion Ion Chromatography for Total Organic Fluorine (TOF) Analysis.

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise thousands of fluorinated chemicals. They are of growing concern because many PFAS compounds are persistent and toxic. Food contact materials (FCMs) containing PFAS pose multiple exposure pathways to humans, prompting 12 states to enact laws banning FCMs with PFAS levels exceeding 100 ppm total organic fluorine (TOF).

OBJECTIVE

While LC-MS is often used to measure targeted PFAS compounds, much of the total PFAS content in the sample may be missed. To understand organic fluorine content in samples more comprehensively, we developed a method using combustion ion chromatography (CIC) to measure TOF and extractable organic fluorine (EOF) in FCMs.

METHODS

This technology utilizes combustion under an oxygen and argon atmosphere. All gaseous, acidic combustion products are collected in water, with ions separated on an ion-exchange column and detected by conductivity. Total fluorine (TF) was measured by combusting 10-50 mg FCM. Total inorganic fluorine (TIF) was measured by extracting cryo-ground FCM with water followed by direct injection to the ion chromatography (IC) system. TOF was then calculated by subtracting TIF from TF. EOF was determined by CIC after extracting analytes from the ground FCM using methanol-acetonitrile (80 + 20, by volume).

RESULTS

The method detection limit (MDL) for TOF is 0.51 ppm, exceeding the sensitivity requirements of current state regulations. A comparison of EOF to TOF revealed that EOF constitutes less than 15% of the TOF in the FCM samples.

CONCLUSION

TOF is a critical metric for assessing PFAS contamination in FCMs, as targeted LC-MS approaches may miss much of the PFAS in the samples.

HIGHLIGHTS

We developed a sensitive and automated method to determine TOF and EOF in FCMs. The method can be used to screen for PFAS in FCMs, ensuring compliance with current regulations on PFAS contamination.