Hu Jingli, Cochran Richard E, Grim Cynthia M, Rumachik Neil G
Thermo Fisher Scientific, 1214 Oakmead Pkwy, Sunnyvale, CA 94085, USA.
J AOAC Int. 2025 May 1;108(3):367-379. doi: 10.1093/jaoacint/qsaf003.
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).
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.
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).
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.
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.
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.
全氟和多氟烷基物质（PFAS）包含数千种含氟化学品。它们日益受到关注，因为许多PFAS化合物具有持久性和毒性。含有PFAS的食品接触材料（FCM）对人类构成多种暴露途径，促使12个州颁布法律，禁止总有机氟（TOF）含量超过100 ppm的FCM。
虽然液相色谱-质谱联用（LC-MS）常用于测量目标PFAS化合物，但样品中大部分总PFAS含量可能会被遗漏。为了更全面地了解样品中的有机氟含量，我们开发了一种使用燃烧离子色谱（CIC）测量FCM中TOF和可萃取有机氟（EOF）的方法。
该技术利用在氧气和氩气气氛下的燃烧。所有气态酸性燃烧产物收集在水中，离子在离子交换柱上分离并通过电导检测。通过燃烧10 - 50 mg FCM测量总氟（TF）。通过用水萃取冷冻研磨的FCM然后直接注入离子色谱（IC）系统测量总无机氟（TIF）。然后通过从TF中减去TIF来计算TOF。使用甲醇 - 乙腈（体积比80 + 20）从研磨后的FCM中萃取分析物后，通过CIC测定EOF。
TOF的方法检测限（MDL）为0.51 ppm，超过了当前州法规的灵敏度要求。EOF与TOF的比较表明，EOF在FCM样品中占TOF的比例不到15%。
TOF是评估FCM中PFAS污染的关键指标，因为目标LC-MS方法可能会遗漏样品中大部分PFAS。
我们开发了一种灵敏且自动化的方法来测定FCM中的TOF和EOF。该方法可用于筛选FCM中的PFAS，确保符合当前关于PFAS污染的法规。
