Flow-injection determination of total organic fluorine with off-line defluorination reaction on a solid sorbent bed

• Published in: Analytica chimica acta Vol. 600; no. 1; pp. 147 - 154
• Main Authors: Musijowski, Jacek, Trojanowicz, Marek, Szostek, Bogdan, da Costa Lima, José Luis Fontes, Lapa, Rui, Yamashita, Hiroki, Takayanagi, Toshio, Motomizu, Shoji
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 26-09-2007; Elsevier
• Subjects: Analytical chemistry; Applied sciences; Carbon; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Flow Injection Analysis - instrumentation; Flow Injection Analysis - methods; Flow-injection analysis; Fluorine - analysis; Fluorine - chemistry; Gas chromatographic methods; Global environmental pollution; Online Systems; Organic Chemicals - analysis; Organic Chemicals - chemistry; Other chromatographic methods; Perfluorocarboxylic acids; Pollution; Sodium biphenyl; Solid-phase extraction; Spectrometric and optical methods; Total organic fluorine; Perfluorocarboxylic acids; Sodium biphenyl; Total organic fluorine; Solid-phase extraction; Flow-injection analysis; Solid phase extraction; Fluorine; Carbon nanotubes; Fluorescence spectrometry; Chemical enrichment; Activated carbon; Model compound; Test method; Flow injection; Liquid chromatography; Fluorides; Potentiometry; Carbon; Defluorination; Sorption; Gas chromatography; Sodium; Time of flight method; Mass spectrometry MS/MS; Environment; Mass spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2007.03.068

Considering recent reports on widespread occurrence and concerns about perfluoroalkyl substances (PFAS) in environmental and biological systems, analysis of these compounds have gained much attention in recent years. Majority of analyte-specific methods are based on a LC/MS/MS or a GC/MS detection, however many environmental or biological studies would benefit from a total organic fluorine (TOF) determination. Presented work was aimed at developing a method for TOF determination. TOF is determined as an amount of inorganic fluoride obtained after defluorination reaction conducted off-line using sodium biphenyl reagent directly on the sorbent without elution of retained analytes. Recovered fluoride was analyzed using flow-injection system with either fluorimetric or potentiometric detection. The TOF method was tested using perfluorocarboxylic acids (PFCA), including perfluorooctanoic acid (PFOA), as model compounds. Considering low concentrations of PFAS in natural samples, solid-phase extraction as a preconcentration procedure was evaluated. Several carbon-based sorbents were tested, namely multi-wall carbon nanotubes, carbon nanofibres and activated carbon. Good sorption of all analytes was achieved and defluorination reaction was possible to carry out directly on a sorbent bed. Recoveries obtained for PFCAs, adsorbed on an activated carbon sorbent, and measured as TOF, were 99.5
±
1.7, 110
±
9.4, 95
±
26, 120
±
32, 110
±
12 for C4, C6, C8, C10 and C12-PFCA, respectively. Two flow systems that would enable the defluorination reaction and fluoride determination in a single system were designed and tested.