The traditional pesticide residue analysis methods include gas chromatography, liquid chromatography, thin layer chromatography and mass spectrometry. These methods are sensitive and accurate, but the pretreatment is cumbersome, the testing time is long, and the instrument is expensive. The use conditions of the instrument and the requirements of the operator are also strict. The pesticide residue detector method can advance the food safety risk monitoring threshold and quickly determine whether the pesticide residue exceeds the standard before the vegetable is listed. This can prevent many pesticide poisoning incidents and ensure the safety of the consumers' diet.
The detector uses an enzyme inhibition method, and the catalytic ability of cholinesterase to substrate decomposition reaction is positively related to its activity. The pesticides in vegetables inhibited the activity of cholinesterase, and the degree of inhibition was linearly related to the residual toxicity of pesticides. Therefore, the activity of cholinesterase can be measured by measuring the rate of change in the catalytic reaction between the vegetable sample and the cholinesterase before and after the effect of the cholinesterase is tested by the pesticide residue detector. Thus, the inhibition rate can be calculated and the sample can be judged by the inhibition rate. The presence of high-dose organic phosphorus pesticides.
Take 2~5g of vegetables (vegetables 2g, tubers 4g), cut into an area of ​​about 1cm2, place in a conical flask, add 10ml of phosphate buffer, shake for 1~2min, and then put the extract into the sample bottle , stand for 2 ~ 3min, used for pesticide residue detector to be tested. In a clean sample bottle, take 0.1ml of enzyme solution and 2.5ml of buffer solution in order, mix, add 0.1ml of color solution, shake and put it at 37°C for 10-15min. Add 0.1 ml substrate solution to the cuvette, then pour the cultured reaction solution into a cuvette, quickly place it into the first detection channel in the test chamber, and carry out a control test using a pesticide residue detector, generally 1 to 3 minutes. .
In researching pesticide residue detectors for analyzing pesticide residues in vegetables, the advantage of this rapid detection method is that the detection time is short, the operation is simple, it can be used continuously, and it is easy to carry. The cost is relatively low, and it is also suitable for on-site use. The instrument can be used as a general site for promotion, and it is also an appropriate choice for applications in farmers' markets, monitoring stations, and fruit and vegetable processing companies.
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