Ion Selective Electrode (ISE) Method for Determination of Total Fluorine and Total Organic Fluorine in Packaging Substrates

• Published in: Methods and protocols Vol. 6; no. 1; p. 10
• Main Authors: Ignacio, Ma Cristine Concepcion D, Curtzwiler, Greg W, Early, Mark R, Updegraff, Katie M, Vorst, Keith L
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.01.2023; MDPI
• Subjects: Combustion; Electrodes; Fluoride; Fluorides; Fluorine; Food; Food contamination; Food packaging; food packaging materials; ion selective electrode (ISE); Laboratories; Methods; Nitrogen; Packaging materials; per- and polyfluoroalkyl substances (PFAS); Perfluoroalkyl & polyfluoroalkyl substances; Process controls; Protocol; Scientific equipment and supplies industry; Stainless steel; total fluorine; total organic fluorine; United States; Massachusetts; United States > US; ion selective electrode (ISE); total fluorine; food packaging materials; total organic fluorine; per- and polyfluoroalkyl substances (PFAS)
• ISSN: 2409-9279; 2409-9279
• DOI: 10.3390/mps6010010

Various testing methods and techniques have been used to identify and quantify per- and polyfluoroalkyl substances (PFAS) in food packaging. A common indirect measurement of PFAS is total fluorine (TF) and total organic fluorine (TOF). These methods are critical in rapidly screening food packaging materials for the >9000 PFAS and are often globally used for regulatory limits. However, this destructive approach requires careful sample preparation, combustion, and the analysis of the solution by a fluoride-specific electrode. The method described herein is a cost-effective, rapid, quantitative, and externally validated initial screening of packaging materials for fluoro-chemistry. This study presents validated protocols for measuring TF and TOF in packaging substrates using oxygen combustion sample preparation coupled with fluoride ion-selective electrode (F-ISE); the materials and required equipment are provided, and the step-by-step procedure from sample preparation to the analysis are described, including critical steps to minimize contamination and interferences during sample preparation.