A novel thermal biosensor based on enzyme reaction for pesticides measurement

摘要

A novel thermal biosensor based on enzyme reaction for pesticides detection has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and identical reference column, which is set for eliminating the unspecific heat. The enzyme reaction takes place in the enzyme reaction column at a constant temperature(40 deg C) realized by a thermoelectric thermostat. Thermosensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to monitor the temperature difference between two effluents from enzyme reaction column and reference column. The ability of this biosensor to detect pesticides is demonstrated by the decreased degree of the hydroiytic heat in two types of thermosensor mode. The hydrolytic reaction is inhibited by 36 percent at 1 mg/L DDVP and 50 percent at 10 mg/L DDVP when cell-typed thermosensor is used. The percent inhibition is 30 percent at 1 mg/L DDVP and 42 percent at 10 mg/L DDVP in tube-typed thermosensor mode. The detection for real sample shows that this biosensor can be used for detection of organophosphate pesticides residue.