Occurrence of Novel Perfluoroalkyl Ether Carboxylic Acids in River Water and Human Urine Quantified by a Simple Liquid-Liquid Microextraction Approach Coupled with LC-MS/MS

Perfluoroalkyl ether carboxylic acids (PFECAs) are a new class of fluorinated compounds that have attracted growing attention. However, many PFECAs exhibit poor sensitivity and high background contamination and are therefore difficult to quantify. Herein, we particularly optimized the instrumental conditions for PFECAs and increased their instrumental sensitivities by 8-200 times. On this premise, large concentration factors or large-volume injection systems were no longer necessary. A simple and sensitive liquid-liquid microextraction method coupled with liquid chromatography-tandem mass spectrometry was developed to quantify 11 emerging PFECAs in river water and human urine. The method quantification limits reached 0.25-1.3 ng/L in river water and 0.50-33 ng/L in urine. Method accuracy ranged from 87%-104% in the two matrices, and interday precision was less than 15% relative standard deviation for all analytes. Application of the method for the Xiaoqing River detected 10 of the 11 emerging PFECAs present at concentrations up to 20,200 ng/L. Perfluoro-2-methoxyacetic acid (PFMOAA) was detected in 100% of human urine samples collected from Huantai (median: 1150 ng/L) and even in 88% of urine samples from Beijing (median: 7.17 ng/L), despite being far from a fluorochemical point source. Further investigations regarding its fate, transport, and exposure pathways are warranted and could benefit from this quantitative method.

Automated summary

A simple and sensitive liquid-liquid microextraction method coupled with liquid chromatography-tandem mass spectrometry was developed to quantify 11 emerging PFECAs in river water and human urine, with excellent detection limits and accuracy. Application of the method for the Xiaoqing River detected 10 of the 11 emerging PFECAs present, and PFMOAA was found in a high percentage of human urine samples, indicating the need for further research on its fate, transport, and exposure pathways.