DETERMINATION OF MURAMIC ACID BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY PLASMA SPRAY MASS-SPECTROMETRY

A high-performance liquid chromatographic-plasma spray mass spectrometric method was developed for the determination of muramic acid, a unique compound present in bacterial peptidoglycan. The method included hydrolysis of bacterial samples by hydrochloric acid, purification using a disposable extraction column, and separation using cation-exchange chromatography with a mobile phase composed of ammonium acetate-trifluoroacetic acid-water. Muramic acid was detected in cells of Bacillus subtilis; the presence of yeast cells (Saccharomyces cerevisiae) in excess amounts did not interfere with the analyses. In contrast to currently applied liquid and gas chromatographic methods, the described method permits highly selective determination of underivatized muramic acid, and may therefore be useful for detecting bacteria and bacterial cell debris in complex biological matrices.