Factors influencing the properties of voltammetric carbon fibre electrodes: the importance of the pH of the medium used for the electrical treatment and of the resin coating of the fibres.
Electrical treatment of resin-coated voltammetric carbon fibre electrodes with triangular voltage at low (1.1) pH resulted in electrodes almost insensitive to ascorbic acid (AA) and dihydroxyphenylacetic acid (DOPAC) while their response to 5-hydroxyindoleacetic acid (5-HIAA) was practically the same as after treatment in the usually employed pH 7.4 medium. Electrodes treated at high pH (12.0), on the other hand, were more sensitive to AA and DOPAC than those treated at pH 7.4 and less sensitive to 5-HIAA. Exposing resin-coated electrodes to the treatment media without electrical treatment was not sufficient to obtain the same results as with the application of the current. Electrodes without resin coating were sensitive to AA without electrical treatment while coated electrodes were not. Electrical treatment increased the sensitivity of non-coated electrodes and rendered coated electrodes even more sensitive than non-coated ones. Treatment of coated electrodes for a maximum sensitivity to 5-HIAA was found to require less time than to obtain maximum sensitivity to the other compounds. Present results suggest that it is possible to prepare selective voltammetric electrodes by choosing the right parameters for their electrical pretreatment.
Hahn
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Cespuglio
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Faradji
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Jouvet
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D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis; D001205:Ascorbic Acid / Q000032:analysis; D002244:Carbon; D000077482:Carbon Fiber; D004560:Electricity; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D012116:Resins, Plant; D012996:Solutions
D000077482:Carbon Fiber; D012116:Resins, Plant; D012996:Solutions; D015102:3,4-Dihydroxyphenylacetic Acid; D006897:Hydroxyindoleacetic Acid; D002244:Carbon; D001205:Ascorbic Acid