Sun X, Gao N, Jin W. Monitoring yoctomole alkaline phosphatase by capillary electrophoresis with on-capillary catalysis-electrochemical detection.
Anal Chim Acta 2006;
571:30-3. [PMID:
17723415 DOI:
10.1016/j.aca.2006.04.063]
[Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2006] [Revised: 04/22/2006] [Accepted: 04/24/2006] [Indexed: 11/24/2022]
Abstract
An electrophoretically mediated microanalysis method for detection of yoctomole (ymol) alkaline phosphatase (ALP) was developed by a combination of on-capillary enzyme-catalyzed reaction and electrochemical detection. In this method, ALP molecules were electrokinetically injected into a capillary of 10 microm i.d. and then electromigrated to the section of the capillary immersed in a warm water bath of 37 degrees C, where ALP reacted for a certain time with disodium phenyl phosphate as the enzyme substrate. ALP could be measured through determining the electroactive product phenol of the enzyme-catalyzed reaction by using electrochemical detection. The phenol concentration was proportional to the mass of ALP. As a catalyst, ALP was not consumed during the reaction, which provided amplification of signal with prolonged the reaction time. In order to enhance the signal-to-noise ratio, the detection end of the capillary was etched to a horn-shape and a single carbon fiber microcylinder electrode of 6 microm in diameter as the working electrode was inserted into the detection end of the capillary. Under these conditions, the mass of ALP as low as 1.2 x 10(-22) mol (72 molecules) or 4.0 x 10(-23) mol (24 molecules) could be detected for the on-capillary reaction time of 15 min or 2h.
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