Determination of adsorbable organically bound fluorine (AOF) and adsorbable organically bound halogens as sum parameters in aqueous environmental samples using combustion ion chromatography (CIC).

Because of their toxicity and biomagnification potential individual perfluoroalkyl and polyfluoroalkyl substances (PFAS) are regularly examined in food and environmental matrices by LC-MS/MS. The combustion ion chromatography (CIC) can be used to determine adsorbable organic fluorine (AOF) in aqueous samples. This report describes the optimization and validation of an automated, robust, cost-efficient and rapid CIC method for the determination of AOF. The analysis of 25 fluorinated organic reference substances was performed with recoveries between 16% and 121%. Water from selected surface waters (n = 74), municipal (n = 116) and industrial wastewaters (n = 33) as well as ground water (n = 93) were analyzed by means of CIC. The AOF values of surface water varied between 2.3 and 24.5 μg/L. The concentrations of AOF in 85% of the wastewater discharges were between 2.0 and 8.5 μg/L, while 15% of the samples were below the limit of quantitation (LOQ = 2 μg/L AOF). In 56% of the ground water samples the values were below the LOQ. In 44% of the surface water samples (n = 41) the values were between 2.0 and 6.1 μg/L AOF. CIC analysis was performed in 22 samples from a chemical company wastewater treatment plant, and 14 individual PFAS were determined by LC-MS/MS. AOF values up to 555 μg/L were found in these samples while the total of the individual PFAS, calculated as fluorine, was 8.8 μg/L. This provides evidence, that CIC covers a huge range of fluoroorganic compounds that are presently not detected by LC-MS/MS. Furthermore, the CIC method allowed the determination of four halogens in 26 surface water samples. This demonstrated that the CIC technique can be used as a powerful screening test to support LC-MS/MS methods, and is also useful to detect organic chlorine, bromine and iodine compounds (AOCl, AOBr and AOI).