Abstract: A method based on the combination of surface plasmon resonance(SPR) with cyclic voltammetry(CV) with the aid of wavelet transform technique was established for the detection of toluidine blue. The gold film of the sensor chip was used as both the generator of SPR measurement and the work electrode of electrochemistry analysis, Ag/AgCl electrode as the reference electrode, and the Pt electrode as the counter electrode. The scans of SPR and CV were performed simultaneously. The results show that due to electro-chemical polymerization of toluidine blue, the potential of oxidation peak shifted positively, the potential of reduction peak remained constant, and the response of SPR fell totally. The results obtained by taking derivative on the SPR response were processed by wavelet transform, and it was found that the response increased linearly with the concentration in range of 8.18—16.35 mmol/L for toluidine blue, with the limit of detection(LOD) of 4.01 mmol/L. Both the linear range and the LOD obtained by the proposed method compare well with the figures of merit given by the CV.

Key words: Surface plasmon resonance(SPR), Cyclic voltammetry(CV), Toluidine blue, Wavelet transform, Kinetic analysis