In the version of this Perspective originally published, in the third paragraph of the section 'Selection and sampling', the sentence beginning 'Pyrolysis-gas chromatography' should have also referred to high-performance liquid chromatography; the sentence has now been amended to read 'Pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) and high-performance liquid chromatography (HPLC) can be used to detect the presence of amino acids62 in any putative proteinaceous sample.'