Pesticide residue detection reagent storage

Before preparation, they are all frozen and have a shelf life of 18 months (12 months for 0-5 ℃ refrigeration).

Preparation of pesticide residue detection reagents

1. Buffer solution: Take one packet and shake well with 510ml distilled water to dissolve, then set aside at room temperature.

2. Substrate: Take a bottle and add 10ml of distilled water, shake well and dissolve. Take 100 μ l when needed, prepare and store at 0-5 ℃.

3. Enzyme solution: Take a bottle and add 10ml of buffer solution, shake well and dissolve. Take 100 μ l when needed, prepare and store at 0-5 ℃.

4. Color developer: Take a bottle and add 10ml of buffer solution, shake well and dissolve. Take 100 μ l when needed, prepare and store at 0-5 ℃.

Preparation of pesticide residue detection reagents and test samples

1. Take representative vegetables to remove soil, weigh 2g with a balance, take the leaf part of leafy vegetables, and take 4g of the skin of fruits.

2. Cut the vegetable sample into a 1cm square and place it in a small beaker. Add 10ml of buffer solution and shake for 1-2 minutes.

3. Take 2.5ml of the supernatant from the soaking solution in the beaker and transfer it into another test tube using a pipette, which is the sample extraction solution.

Pesticide residue detection reagent testing

Take a test tube and add 2.5ml of buffer as a blank control. Then, add 100ul of enzyme solution and 100ul of color reagent to each sample extraction tube in sequence, shake well, and let it sit for 10 minutes. After shaking well, pour 100ul of substrate into a colorimetric dish and immediately put it into the instrument. Press the "Start Blank Analysis" button and wait for the test results. (After conducting the control, the next step of the test is to start sample analysis, but after restarting or replacing the reagent, a blank control needs to be performed again)

Note: The blank control value △ AO with a detection time of 3 minutes should be ≥ 0.3; When the temperature is below 20 ℃, heating measures should be taken to improve the accuracy of the data; If △ AO<0.3 and unconditional heating is applied, the enzyme levels of the blank and sample can be doubled.

Determination of pesticide residue detection reagent results

When the inhibition rate is less than 50%, it is judged as qualified; When the inhibition rate is ≥ 50%, pesticide residue exceeds the standard, and quantitative testing can be conducted if necessary.

Precautions for pesticide residue detection reagents

1. When using reagents, prepare one bottle after another and shake well before use;

2. Reagents should avoid cross contamination, and the aspirated reagents should not be returned to the bottle;

Packaging specifications for pesticide residue detection reagents

500 portions, 1 bottle each for enzyme, substrate, and color reagent, and 2 packs of extraction reagents.

This article's website: