Detection of underivatized carbohydrates in capillary electrophoresis with a bienzyme electrode. 1997

H Wei, and T Wang, and S F Li
Department of Chemistry, National University of Singapore, Republic of Singapore.

A new approach to detect underivatized carbohydrates in capillary zone electrophoresis (CZE) with a bienzyme electrode is described. The bienzyme electrode is based on immobilization of two enzymes, glucose oxidase and amyloglucosidase, on a platinum microelectrode. Maltose and glucose were used as substrates to establish the method and study its feasibility. Using this electrode, underivatized glucose and maltose were determined after separation in 60 mM borate buffer (pH 9.3) by CZE. A liquid junction, between the surface of the bienzyme electrode and the outlet of the separation capillary, was used to lower the pH of the eluting separation borate buffer so that the immobilized enzymes could maintain high activities. The detection limits were 0.17 mM for maltose and 0.35 mM for glucose. The effects of borate ion and pH on the responses of the bienzyme electrode to maltose and glucose are discussed. The bienzyme electrode did not show any decay in responses to maltose or glucose during one week of continuous operation.

UI MeSH Term Description Entries
D008320 Maltose A dextrodisaccharide from malt and starch. It is used as a sweetening agent and fermentable intermediate in brewing. (Grant & Hackh's Chemical Dictionary, 5th ed)
D008839 Microelectrodes Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed) Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
D010984 Platinum A heavy, soft, whitish metal, resembling tin, with atomic number 78, atomic weight 195.084, symbol Pt. It is used in manufacturing equipment for laboratory and industrial use. It occurs as a black powder (platinum black) and as a spongy substance (spongy platinum) and may have been known in Pliny's time as "alutiae". Platinum Black
D001881 Borates Inorganic or organic salts and esters of boric acid. Borate
D002021 Buffers A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer. Buffer
D002241 Carbohydrates A class of organic compounds composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n. The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrate
D004800 Enzymes, Immobilized Enzymes which are immobilized on or in a variety of water-soluble or water-insoluble matrices with little or no loss of their catalytic activity. Since they can be reused continuously, immobilized enzymes have found wide application in the industrial, medical and research fields. Immobilized Enzymes,Enzyme, Immobilized,Immobilized Enzyme
D005087 Glucan 1,4-alpha-Glucosidase An enzyme that catalyzes the hydrolysis of terminal 1,4-linked alpha-D-glucose residues successively from non-reducing ends of polysaccharide chains with the release of beta-glucose. It is also able to hydrolyze 1,6-alpha-glucosidic bonds when the next bond in sequence is 1,4. 1,4-alpha-Glucosidase, Exo,Amyloglucosidase,Exo-1,4-alpha-Glucosidase,Glucoamylase,gamma-Amylase,Glucoamylase G1,Glucoamylase G2,1,4-alpha-Glucosidase, Glucan,Exo 1,4 alpha Glucosidase,Glucan 1,4 alpha Glucosidase,gamma Amylase
D005947 Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D005949 Glucose Oxidase An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC 1.1.3.4. Microcid,Oxidase, Glucose

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