HPLC WITH ELECTROCHEMICAL AND FLUORESCENCE DETECTION OF THE OPA 2-METHYL-2-PROPANETHIOL DERIVATIVE OF FUMONISIN B-1

The o-phthalaldehyde (OPA) derivative of fumonisin B-1 was prepared in the presence of 2-methyl-2-propanethiol (tert-butyl thiol). A hydrody namic voltammogram for the derivative indicated that the optimum volta ge for maximum electrochemical response was +0.7 V. The electrochemica l response of the OPA/tert-butyl derivative was unstable. However, the fluorescence response was found to be stable for over an hour after a n initial 30 minute reaction time. The minimum detectable limit (MDL) of the OPA/tert-butyl derivative using fluorescence detection was 30 n g/ml as compared to 250 ng/ml for electrochemical detection.