Aflatoxin B1 fast test card operation instructions

Aflatoxin B1 fast test card

operation instructions

(Colloidal gold method)

1. Principle and Application

This product is made by the principle of competitive inhibition colloidal gold immunochromatography, and is used to detect Aspergillus flavus B1 (AFB1) in grains, feedstuffs and other samples.

After the sample solution is dropped into the sample adding hole of the detection card, the Aspergillus flavus B1 in the sample solution is combined with the gold labeled antibody, thus preventing the gold labeled antibody from combining with the Aspergillus flavus B1 conjugate on the cellulose membrane. When the content of Aspergillus flavus B1 in the sample solution is greater than the detection limit, the detection line does not show color, and the result is positive; When the content of Aspergillus flavus B1 in the sample solution is less than the detection limit, the detection line will appear purple red, and the result is negative.

2. Technical indicators

2.1 Sensitivity of reagent card: 2ppb (ng/ml)

The final detection limit for the sample must be determined by multiplying the sensitivity of the reagent card by the dilution ratio of the sample treatment.

2.2 Lower limit of sample detection:

Cereals, feed, grain and oil...... 20ppb

Cereals, feed (must be blown dry)...... 5ppb

3. Kit composition

Detection card: 40 pieces/box

Instructions: 1 copy

4. Required equipment and reagents

4.1 Instruments: homogenizer, oscillator, centrifuge, graduated pipette, balance (sensitivity 0.01g)

4.2 Micro Pipette: single channel 20 µ l-200 µ l, 100 µ l-1000 µ l

4.3 Reagent: Methanol, n-hexane

5. Sample pretreatment

5.1 Instructions before sample processing:

The experimental equipment must be clean and use a disposable suction head to avoid contamination and interference with the experimental results.

5.2 Preparation:

Solution 1: Sample extraction solution

70% methanol, i.e. V methanol: V deionized water=7:3.

5.3 Sample preprocessing steps:

5.3.1 Cereals and feed

1) Weigh 2g of crushed sample into a centrifuge tube, and add sample extraction solution according to different detection limit requirements in the following table

Shake for 5 minutes at room temperature of 4000 rpm/separation heart for 5 minutes.

Take 0.1ml of supernatant, add 0.4ml of deionized water, and mix well for later use.

5.3.2 Cereals and feed (must be blown dry)

If the lower detection limit is required to be 5ppb, the following operations can be performed:

1) Weigh 2g of crushed sample into a centrifuge tube, add 4ml of sample extraction solution, shake for 5 minutes, and separate at room temperature of 4000 rpm for 5 minutes;

2) Take 1ml of the upper liquid and dry it with nitrogen or air at 50-60 ℃;

3) Firstly, add 0.25ml of 70% methanol to dissolve the remaining residue and shake vigorously for 2 minutes; Add another 1ml of deionized water and mix well for later use. (Note: The order of adding methanol and water in this step cannot be reversed)

5.3.3 Grain and oil (vegetable oil, sesame oil, salad oil, Peanut oil, etc.)

1) Weigh 2g of the sample into a centrifuge tube, and add the sample extraction solution according to different detection limit requirements in the following table

Then add 8ml of n-hexane, shake for 5 minutes, and separate at room temperature of 4000 rpm for 5 minutes.

Remove the upper liquid, take 0.1ml of the lower liquid and add 0.4ml of deionized water, mix well and set aside.

6. Experimental Steps

6.1 Tear open the aluminum foil packaging bag of the inspection card, take out the inspection card, and place it on a flat and clean tabletop.

6.2 Suck the prepared sample liquid with a matching pipette, and slowly drop 2-3 drops (about 60ul) into the sample hole (S) one by one (foam should be avoided).

6.3 Leave at room temperature for 8-10 minutes to determine the results. Results exceeding 10 minutes can only be used as a reference.

7. Result judgment

Negative: Both the C and T lines show color, indicating that the concentration in the sample is below the detection limit or does not contain.

Positive: The C line shows red, while the T line does not show color, indicating that the concentration in the sample is above the detection limit.

Invalid: The absence of a quality control C-line indicates an incorrect operating process or a failure of the detection card.

Negative positive invalid

8. Precautions

8.1 Products that have expired or have damaged aluminum foil bags cannot be used.

8.2 When removing the detection card from the refrigerator, it should be restored to room temperature before opening. The opened detection card should be used as soon as possible to avoid failure due to moisture.

8.3 Do not touch the white film surface in the center of the detection card.

8.4 Droppers should not be mixed to avoid cross contamination.

8.5 The sample solution to be tested should be clear, free from turbid particles, and bacterial contamination, otherwise it may lead to abnormal phenomena such as blockage and unclear color development, which may affect the judgment of experimental results.

9. Storage and shelf life

Storage conditions: The reagent kit should be stored in a dry environment at 2-30 ℃.

Shelf life: The product has a validity period of 1 year, and the production date can be found in the packaging box.