title: Targeted metabolomic analysis of Escherichia coli by desorption electrospray ionization and extractive electrospray ionization mass spectrometry.
abstract: Desorption electrospray ionization (DESI) was utilized to monitor the presence of targeted central carbon metabolites within bacterial cell extracts and the quench supernatant of Escherichia coli. The targeted metabolites were identified through tandem mass spectrometry (MS/MS) product ion scans using collision-induced dissociation in the negative ion mode. Picogram detection limits were achieved for a majority of the metabolites during MS/MS analysis of standard metabolite solutions. In a [U-(13)C]glucose pulse experiment, where uniformly labeled glucose was fed to E. coli, the corresponding fragment ions from labeled metabolites in extracts were generally observed. There was evidence of matrix effects including moderate suppression by other metabolites within the spectra of the labeled and unlabeled extracts. To improve the specificity and sensitivity of detection, optimized in situ ambient chemical reactions using DESI and extractive electrospray ionization (EESI) were carried out for targeted compounds. This study provides the first indication of the potential to perform in situ targeted metabolomics of a bacterial sample via ambient ionization mass spectrometry.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Ayanna U
authors.initials: AU
authors.lastname: Jackson
authors.forename: Sean R
authors.initials: SR
authors.lastname: Werner
authors.forename: Nari
authors.initials: N
authors.lastname: Talaty
authors.forename: Yishu
authors.initials: Y
authors.lastname: Song
authors.forename: Karinna
authors.initials: K
authors.lastname: Campbell
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
authors.forename: John A
authors.initials: JA
authors.lastname: Morgan
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism*; D005947:Glucose / Q000032:analysis; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013194:Staining and Labeling; D053719:Tandem Mass Spectrometry; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D005947:Glucose