Amperometric Detection of Some Catechol Derivatives and 0-aminophenol Derivative with Laccase lmmobilized Electrode: Effect of Substrate Structure

초록

DeniLiteTM laccase immobilized Pt electrode was used for amperometric detection of some catechol derivatives and o-aminophenol (OAP) derivative by means of substrate recycling. In case of catechol derivatives, the obtained sensitivities are 85, 79 and 57 nA/M with linear ranges of 0.6~30, 0.6~30 and 1~25 M and detection limits (S/N=3) of 0.2, 0.2 and 0.3 M for 3,4-dihydroxycinnaminic acid (3,4-DHCA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), respectively. In case of OAP derivative, the obtained sensitivity is 237 nA/M with linear range of 0.2~15 M and detection limit of 70 nM for 2-amino-4-chlorophenol (2-A-4-CP). The response time (t90%) is about 2 seconds for each substrate and the long-term stability is around 40~50 days for catechol derivatives and 30 days for 2-A-4-CP with retaining 80% of initial activity. The optimal pHs of the sensor for these substrates are in the range of 4.5~5.0, which indicates that stability of the enzymatically oxidized product plays a very important role in substrate recycling. The different sensitivity of the sensor for each substrate can be explained by the electronic effect of the substituent on the enzymatically oxidized form.

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