Tris(hydroxymethyl)phosphine, P(CH2OH)3 - A convenient and effective new reagent for the fixation of protein samples for SEM imaging

Tris(hydroxymethyl)phosphine [P(CH2OH)3, THP] is demonstrated to be an alternative fixative to glutaraldehyde for preparation of proteinaceous specimens for SEM analysis. THP is easily prepared from commercially-available [P(CH2OH)4]Cl, and unlike many other alkylphosphines, is reasonably air-stable [>7 days at pH 7-8]. Experiments carried out with chicken breast muscle, cross-sectioned perpendicular to the muscle fibres and imaged using SEM, indicate that THP effectively fixes the muscle structure with minimal discolouration of the sample.