A Thermal Biosensor Based on ThermoelectricModule for Organophosphate Pesticides Detection

摘要

Organophosphate pesticides are used on a very large scale, and their detection is ofgreat interest. A thermal biosensor based on thermoelectric module for organophosphatepesticides detection has been developed. The thermosensor, which is constructed using athermoelectric module as sensitive component, has high sensitivity of 1.8 mV/K in real testcondition. The hydrolytic reaction takes places in the enzyme reaction column at a constanttemperature (40 °C±0.1 °C), when the substrate is introduced in system. The use of an identicalreference column eliminates virtually the influence of unspecific heat which are not produced bythe enzymic reaction. The temperature difference of the two flows passing through the enzymereaction column and reference column is measured by the thermosensor. The ability of thisbiosensor to detect pesticides is demonstrated by the decreased degree of the hydrolytic heat.Thermoelectricity potential caused by hydrolytic reaction without inhibition is about 5 mV, when theactivity of immobilized enzyme is 1.28 U/g, substrate concentration is 8 mmol/L and flux is 1.0mL/min. The hydrolytic reaction is inhibited by 36% when pesticide (dichlorvos, DDVP)concentration is 1 mg/L, incubation time is 10 minutes and the activity of immobilized enzyme is0.78 U/g. The experiments show that this biosensor can be used for detection of organophosphatepesticide residue.