Sub-ppm determination of perfluorinated carboxylic acids in solution by UV-vis high-performance liquid chromatography through solid phase extraction.

This study investigated a novel and sensitive analytical method based on a simple heat-based derivatization using 3-bromoacetyl coumarin as the reagent and analysis with a HPLC-UV system or just a UV-vis spectrometer to allow the sub-ppm determination of PFCAs in water solution with the potential for utilization in simple laboratories and field laboratory scenarios. A Strata-X-AW cartridge was used for the solid phase extraction (SPE) procedure and higher than 98% recoveries were obtained. The derivatization condition showed that a high efficiency of peak separation was obtained with obviously different retention time among various PFCAs derivatives using HPLC-UV analysis. The derivatization stability and repeatability showed favorable results with stable derivatized analytes for ≤12 h and a relative standard deviation (RSD) of <2% for all repetitions. The limit of detection for the HPLC-UV analysis was between 0.1 ppm and 0.5 ppm. A satisfactory linearity response was found with R² >0.998 for all individual PFCA compounds. The limit of detection for simple UV-Vis analysis was <0.0003 ppm to measure the presence of PFCAs. Contamination of standards with humic substances and measurement of industrial samples in a complex wastewater matrix showed no adverse effects on the accuracy of PFCA determination by using the developed methodology.