A novel approach to the sensing of weak bases

A weak base present in an unbuffered solution containing α-tocopherol (α-T) was found to give rise to a new peak (termed as the oxidation prepeak) on the voltammogram of α-T at a potential less positive than that for the oxidation peak of α-T. The half-peak potential of the oxidation prepeak for a w...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2005-07, Vol.108 (1), p.858-862
Main Authors: Kusu, Fumiyo, Oshiba, Kazunao, Kotani, Akira
Format: Article
Language:English
Subjects:
Acetonitrile
Actuators
Benzodiazepines
Detection
Electrochemical cells
Electrolysis
HPLC
Liquid chromatography
Oxidation
Voltammetry
Weak base
α-Tocopherol
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Summary:A weak base present in an unbuffered solution containing α-tocopherol (α-T) was found to give rise to a new peak (termed as the oxidation prepeak) on the voltammogram of α-T at a potential less positive than that for the oxidation peak of α-T. The half-peak potential of the oxidation prepeak for a weak base shifted to a positive value along with an increase in p K b of the base. On voltammograms of flunitrazepam, nitrazepam, bromazepam, chlordiazepoxide, and medazepam each in an acetonitrile solution containing 3 mM α-T and 50 mM LiClO 4, the prepeak heights were proportional to their concentration. Based on these findings, a novel approach to the sensing of such weak bases by means of linear sweep voltammetry and controlled potential electrolysis using a flow-type electrochemical cell is proposed. Moreover, an electrochemical detection method for high-performance liquid chromatography (HPLC) was developed for determining benzodiazepines.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2004.11.030