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Indirect Measurement of Yoctomole Alkaline Phosphatase by Capillary Electrophoresis with Electrochemical Detection
Author(s) -
Sun Xuemei,
Weng Qianfeng,
Jin Wenrui
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200402880
Subject(s) - capillary electrophoresis , detection limit , chemistry , saturated calomel electrode , electrode , chromatography , capillary action , substrate (aquarium) , analytical chemistry (journal) , alkaline phosphatase , reference electrode , electrochemistry , materials science , enzyme , biochemistry , oceanography , composite material , geology
A method for indirectly detecting yoctomole (ymol) alkaline phosphatase was developed by capillary electrophoresis with electrochemical detection. In this method, disodium phenyl phosphate was used as the enzyme substrate and the product (phenol) of its hydrolysis reaction catalyzed by alkaline phosphatase was detected at the carbon fiber electrode. The optimum conditions of detection are 1.0×10 −2 mol/L Na 2 B 4 O 7 (pH 9.8) for the running buffer; 1.00×10 −3 mol/L disodium phenyl phosphate for the enzyme substrate; 20.0 kV for the separation voltage; 5 kV and 10 s for the injection voltage and injection time; 1.05 V (vs. saturated calomel electrode) for the detection potential and 10 min for the incubation time, respectively. In order to enhance the ratio of signal to noise, the shape and size of the working electrode, the shape of detection end of the capillary, and the capillary/electrode alignment method were studied in detail. When a single carbon fiber microcylinder electrode of 6 μm, a capillary of 10 μm ID with the etched detection end and the in‐capillary alignment were used, a ymol mass limit of detection for alkaline phosphatase was achieved.