d-alanine and diaminopimelic acid originating from bacterial peptidoglycans and hydroxy fatty acids from lipopolysaccharides ( endotoxins ) were analysed by gas chromatography using a chiral column ( chirasil-val as stationary phase ) and selected-ion monitoring detection with negative-ion chemical-ionization mass spectrometry .
C0023810
lipopolysaccharides
C0014264
endotoxins