title: Analysis of a stable halogenated derivative of muramic acid by gas chromatography-negative ion chemical ionization tandem mass spectrometry.
abstract: Muramic acid (Mur) is present in the cell wall of Eubacteria and serves as a chemical marker for the trace detection of bacteria and bacterial cell wall debris in complex matrices. There have been numerous studies using a variety of derivatives of Mur, particularly in combination with gas chromatography-tandem mass spectrometry (GC-MS-MS) where the detection limit has been steadily lowered. A stable, halogenated derivative, the pentafluorobenzyl oxime (PFBO) acetate of Mur, has been developed by others and successfully used for GC with electron-capture detection. The current report is the first use of this derivative for GC-MS-MS analysis of Mur, or indeed any other carbohydrate, using negative ion chemical ionization (NICI) with GC-MS-MS. Mur was readily detected in settled surface dust (166 ng/mg), as well as dust collected from indoor air (1.4-5.9 ng/mg). Analyses of Mur as a PFBO acetate by GC-NICI-MS-MS or as alditol acetates by electron impact GC-electron impact ionization MS-MS serve as complementary approaches for trace detection in complex matrices.
authors.affiliation: Department of Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia 29208, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kozar
authors.forename: Alvin
authors.initials: A
authors.lastname: Fox
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006219:Halogens / Q000737:chemistry*; D009112:Muramic Acids / Q000032:analysis*
chemical_list: D006219:Halogens; D009112:Muramic Acids