Determination of perfluoroalkyl substances in food packaging in Taiwan using ultrasonic extraction and ultra-performance liquid chromatography/tandem mass spectrometry.

Perfluoroalkyl substances (PFASs), as coating materials, possess oil-resistant and waterproof properties. However, their persistency and toxicity have caused concerns. This study developed a method for determining five types of 20 PFASs with ultra-performance liquid chromatography/tandem mass spectrometry, and measured seven categories of 32 commercial samples of oil-resistant food packaging in Taiwan. The assay was validated according to the specification of Taiwan Food and Drug Administration (TFDA). Samples of 100 cm were cut into pieces and were ultra-sonicated in 20-mL methanol at 50 °C for 45 minutes. The extracts were concentrated to 1 mL for instrumental analysis. Most matrix effect factors and extraction efficiencies of the analytes were 50%-80% and 52%-99%, respectively. Most limits of detection and limits of quantification were between 0.07-11.3 ng/dm and 0.17-18.3 ng/dm, respectively. Most recoveries ranged from 70% to 117% at three tested levels, and the precisions (%RSD) were lower than 19%. Microwave popcorn paper contained more types and higher levels of PFASs than other packaging, with perfluoroalkyl acids at 8.3-1960 ng/dm and fluorotelomer alcohols (FTOHs) at 9.7-7188 ng/dm. High concentrations of FTOHs were also observed in one oil-proof paper bag at 454-2595 ng/dm and in one French fries paper bag at 22.4-167 ng/dm.