In order to quickly detect the harmful substances in food

a temperature controllable portable food safety detector which can be used in the field test is designed.The detector use spectrophotometry analysis to measure the concentration of solution.It adopts DS18B20 temperature sensor and semiconductor device to control the temperature of reaction solution.TSL230 optical frequency converters are applied for data collecting.Datas are processed by PIC16F877 microcontroller to achieve temperature and concentration digital display.The result of experiment shows that the system has the advantage of easy operating and convenient controlling of the temperature of the reaction solution to suit different test objects.And the measurement error of concentration of sodium nitrite and formaldehyde are less than 10 %.The measurement accuracy of the designed instrument meets the national standards.