Trends, analytical methods and precision in the determination of perfluoroalkyl acids in human milk

The review describes trends and precision in analytical methods measuring perfluoroalkyl acids (PFAAs) in human milk [e.g., perfluorooctane sulfonic acid (PFOS)]. A worldwide interlaboratory proficiency test with two human milk samples is reported showing a large inter-laboratory variation. High relative standard deviations (RSDs) for the 20 laboratories for PFOS (38, 49%) and perfluorooctanoic acid (PFOA, 53, 71%) indicates that there is a performance variation in the current data.Assessing the worldwide effectiveness of declining levels as a result of regulations and bans demands analytical precision and accuracy. The Stockholm Convention aims to reduce human levels by 20%. Assessing such a reduction of PFOS levels in human milk is currently impossible due to analytical difficulties. Crucial for improving precision and accuracy is better control of contamination and achieving higher sensitivity and selectivity in quantitative analysis.

► Summary of methods reported for analytical determination of PFAAs in human milk.
► Discussion of trends in the analysis of human milk and need for future development.
► Presentation of the first world-wide proficiency testing of PFAAs in human milk.
► Comparing the accuracy of laboratories in the world-wide proficiency testing of PFAAs.