title: On-line sample preconcentration with chemical derivatization of bacterial biomarkers by capillary electrophoresis: a dual strategy for integrating sample pretreatment with chemical analysis.
abstract: Simple, selective yet sensitive methods to quantify low-abundance bacterial biomarkers derived from complex samples are required in clinical, biological, and environmental applications. In this report, a new strategy to integrate sample pretreatment with chemical analysis is investigated using on-line preconcentration with chemical derivatization by CE and UV detection. Single-step enantioselective analysis of muramic acid (MA) and diaminopimelic acid (DAP) was achieved by CE via sample enrichment by dynamic pH junction with ortho-phthalaldehyde/N-acetyl-L-cysteine labeling directly in-capillary. The optimized method resulted in up to a 100-fold enhancement in concentration sensitivity compared to conventional off-line derivatization procedures. The method was also applied toward the detection of micromolar levels of MA and DAP excreted in the extracellular medium of Escherichia coli bacterial cell cultures. On-line preconcentration with chemical derivatization by CE represents a unique approach for conducting rapid, sensitive, and high-throughput analyses of other classes of amino acid and amino sugar metabolites with reduced sample handling, where the capillary functions simultaneously as a concentrator, microreactor, and chiral selector.
authors.affiliation: Department of Chemistry, McMaster University, Hamilton, Canada.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Ptolemy
authors.forename: Marianne
authors.initials: M
authors.lastname: Le Bihan
authors.forename: Philip
authors.initials: P
authors.lastname: Britz-McKibbin
mesh_terms: D000111:Acetylcysteine; D001419:Bacteria / Q000737:chemistry / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods*; D015415:Biomarkers / Q000032:analysis; D003470:Culture Media / Q000737:chemistry; D003960:Diaminopimelic Acid / Q000032:analysis; D019075:Electrophoresis, Capillary / Q000379:methods*; D004926:Escherichia coli / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009112:Muramic Acids / Q000032:analysis; D013237:Stereoisomerism; D009764:o-Phthalaldehyde
chemical_list: D015415:Biomarkers; D003470:Culture Media; D009112:Muramic Acids; D003960:Diaminopimelic Acid; D009764:o-Phthalaldehyde; D000111:Acetylcysteine