Per/Polyfluoroalkyl substances (PFAS) are a class of artificially synthesized fluorinated organic compounds, which contain stable C-F bonds and sulfonic acid/carboxylic acid functional groups in their structure. Therefore, they have excellent hydrophobic, oleophobic, and stable physicochemical properties, and are widely used in packaging materials, textiles, papermaking, surface treatment agents, leather, intermediates, and other fields. However, due to the high bond energy and good stability of the C-F bond in the PFAS structure, it is difficult to be destroyed in the environment and organisms. Therefore, the transmission of PFAS through the food chain has bioaccumulation, which may cause harm such as human hepatotoxicity, immunotoxicity, endocrine disruption, and potential carcinogenicity. Studies in multiple countries/regions have shown that PFAS is commonly present in environmental water bodies and soils, and has also been detected in animal organs and serum. Regarding the pathway of human intake of PFAS, it is generally believed that dietary intake is the main approach [1-2]. Therefore, the importance of establishing efficient detection methods for multiple PFAS in various food matrices is self-evident.

The LC-MS/MS based analysis method is widely used in the detection of PFAS due to its high sensitivity and selectivity advantages. Considering the requirement of low quantification limit for PFAS, an Agilent 6495D triple quadrupole liquid chromatography-mass spectrometry system was used in this experiment. One of the important goals of establishing a PFAS analysis method for food is to effectively remove matrix co extracts during sample pretreatment and be applicable to different types of sample matrices. The solid-phase extraction method based on weak anion exchange (WAX) mechanism is one of the commonly used methods. It is based on the retention of carboxylic acid or sulfonic acid groups contained in the PFAS structure, followed by washing to remove impurities. After washing, it is concentrated by nitrogen blowing. The entire process involves multiple steps and there is a possibility of introducing more background interference; In addition, dispersed solid phase extraction (dSPE) has also been reported for the detection of PFAS in food. Although the process is simple, it cannot effectively remove complex matrix interference, which poses a challenge to achieving high-sensitivity analysis.

Due to the wide variety of food types, Agilent Captiva EMR PFAS Food is a purification column developed for food matrices using a hybrid mode, and includes multiple options for different sample matrix types. Among them, Captiva EMR PFAS Food I (340 mg or 680 mg, 6 mL) is suitable for processing fresh plant-based foods such as vegetables, fruits, grains, and baby food; PFAS Food II (750 mg, 6 mL) is suitable for processing animal source foods (such as muscle, edible viscera and seafood), dry plant seed foods (such as soybeans, peanuts, etc.), infant formula milk powder, feed and oil and other matrices. There are slight differences in the use methods between the two. Agilent has launched a complete solution for treating various food matrices using Captiva EMR PFAS Food for reference [3-8]. On this basis, this application uses Agilent Captiva EMR PFAS Food and Bond Elut PFAS Wax to purify PFAS in rice, spinach, and fish sample matrices, and compares the purification effects of the two methods. The difference in effectiveness between the two methods can provide important references for selecting more efficient sample pretreatment methods in food.