title: Sequential capillary electrophoresis analysis using optically gated sample injection and UV/vis detection.
abstract: We present sequential CE analysis of amino acids and L-asparaginase-catalyzed enzyme reaction, by combing the on-line derivatization, optically gated (OG) injection and commercial-available UV-Vis detection. Various experimental conditions for sequential OG-UV/vis CE analysis were investigated and optimized by analyzing a standard mixture of amino acids. High reproducibility of the sequential CE analysis was demonstrated with RSD values (n = 20) of 2.23, 2.57, and 0.70% for peak heights, peak areas, and migration times, respectively, and the LOD of 5.0 μM (for asparagine) and 2.0 μM (for aspartic acid) were obtained. With the application of the OG-UV/vis CE analysis, sequential online CE enzyme assay of L-asparaginase-catalyzed enzyme reaction was carried out by automatically and continuously monitoring the substrate consumption and the product formation every 12 s from the beginning to the end of the reaction. The Michaelis constants for the reaction were obtained and were found to be in good agreement with the results of traditional off-line enzyme assays. The study demonstrated the feasibility and reliability of integrating the OG injection with UV/vis detection for sequential online CE analysis, which could be of potential value for online monitoring various chemical reaction and bioprocesses.
authors.affiliation: Faculty of Chemistry, Northeast Normal University, ChangChun, Jilin, P. R. China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Liu
authors.affiliation: Faculty of Chemistry, Northeast Normal University, ChangChun, Jilin, P. R. China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Tian
authors.affiliation: Faculty of Chemistry, Northeast Normal University, ChangChun, Jilin, P. R. China.
authors.forename: Mohamed Amara
authors.initials: MA
authors.lastname: Camara
authors.affiliation: Faculty of Chemistry, Northeast Normal University, ChangChun, Jilin, P. R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Guo
authors.affiliation: Faculty of Chemistry, Northeast Normal University, ChangChun, Jilin, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Yang
mesh_terms: D001216:Asparagine / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D001224:Aspartic Acid / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D057230:Limit of Detection; D008956:Models, Chemical; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D001224:Aspartic Acid; D001216:Asparagine
keywords: Capillary electrophoresis; Online derivatization; Optically gated injection; Sequential analysis; UV/vis