The present invention relates to a method of preparing N-acyl amino acids selected from N-acyl cysteine compounds, N-acyl serine compounds, N-acyl aspartic acid compounds and N-acyl glutamic acid compounds. The present invention also relates to the use of N-acyl cysteine, N-acyl serine, N-acyl aspartic acid and N-acyl glutamic acid surfactants, in removing per- and poly-fluoroalkyl substances (PFASs) from mixtures containing PFASs, such as soil and groundwater contaminated with PFASs and for use in cleaning compositions, detergent compositions and toothpaste compositions.
