Self-service detection platform of pesticide residue based on enzyme inhibitory method

Abstract: Aiming at the food safety, especially the pollution and residue of pesticides and additives in agricultural products such as fruits and vegetables, a self-service detection platform of pesticide residue based on enzyme inhibition method was designed and developed. Most of the accurate detection methods for pesticide residue are only suitable for laboratory testing, and the macroscopic results of enzyme inhibition test paper are not reliable and precise enough. The detection results of the test paper are related to operations progresses such as the inhibition time, the inhibition temperature and the amount of eluent. And the lowest limits of detection of some pesticides of the test paper are higher than the pesticide residue limits in national standard. This leads that the enzyme inhibition tests paper was only suitable for qualitative judgment. In the self-service detection platform of pesticide residue, the automation technology is used to set the standardized detecting parameter during the progress of enzyme inhibition method detection. In the experiments the inhibition time was set as 15 minutes, the inhibition temperature was set as 35℃, and the amount of eluent was set as 100?μL. The uniform testing parameters could ensure the agreements of different tests. The image recognition technology was used to make the automatic processing of test paper, which includes the photo automatic recognition, identify and extract useful data from the pesticide residue test paper, fine analysis and multistage division of the raw detection result. The self-service detection platform had built-in image.vi software based on Lab view. The image.vi software could get the real-time video and screenshots of the detection progress. The software had the function of automatically locating and selecting the image of the circle test result area, which could automatically select the right side of the test paper and take pictures with the color image area of test results. The software could enlarge the color display image of the test results, and used the Abiro color sampler automatically to get some parameters such as pure color tone, saturation, brightness and RGB value. By analyzing the differences between the parameters of the test results under different pesticide contents, it was found that there is an approximate linear relationship between the color saturation parameters and the pesticide residues. By comparing the detection results of the self-service detection platform to gas chromatography, the color saturation parameters are correspondence to five levels for different pesticide residue degree according to the national food safety standard: Maximum residue limits for pesticides in food GB 2763-2016. And the 5 security levels was established in which the saturation S>122 is the first level of no residue, the saturation 99