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Nitrofurans SEM Residue Rapid Test Uncut Sheet
SEM Rapid Test is a competitive immunoassay for the semi-quantitative detection of the presence of SEM residue in animal’s tissue.
Cut-off: 1 ppb
PRINCIPLE OF THE ASSAY
SEM Rapid Test is based on competitive lateral flow immunochromatographic assay. The SEM -conjugate in the test zone will capture the immuno-gold (colloid gold- SEM antibody conjugate), when there is very little dissociative SEM in the samples. A visible red test band indicates a negative result when the control line (C zone) shows that the card is valid. The test band (T zone) will be not visible if SEM is present in concentration of 1 ppb and above which explains a positive result.
-10×foil pouches each containing a cassette and desiccant
-3×assay buffer (2×Diluent A, 1×Diluent B)
-20×pipettes, 12×centrifugal tubes (2×15 mL, 10×1.5 mL )
-Weigh out 1 g of the homogenized sample and place it into a 15 mL centrifugal tube. Add 4 mL of distilled water, 0.5 mL of 1 M HCl and 100 μL (fish, shrimp) or 200 μL (chicken, prok) of Diluent A into the tube and shake for 1 min. Put the tube in incubator (37 °C) for 16 hours.
-Add 5 mL of 0.1 M K2HPO4, 0.4 mL of 1 M NaOH and 4 mL of Ethyl acetate. Mix well for 1 min. Do centrifugation at 3000 rpm for 10 min.
-Collect accurately 2 mL of supernatant (ethyl acetate layer) into a small container (beaker or tube). Dry the liquid by 50°C of Nitrogen flow.
-Add 1 mL of n-hexane to totally dissolve the residue, and then add 0.2 mL of Diluent B. Mix well for 1 min and place it into a 1.5 mL of centrifugal tube.
-Do centrifugation at 3000 rpm for 10 minutes. If layering does not appear, mix the liquid well, put it in boiling water for 3 min and do centrifugation again.
-Take out the cassette from the foil pouch and place it horizontally.
-Gradually drip 3 drops of under layer liquid into the assay sample hole “S”.
-Interpret the result in 10 - 15 min. Result after 15 min is only considered as reference.
INTERPRETATION OF RESULTS
Positive: Only one clear band in C zone indicates a positive result. If a vague T band can be seen but apparently weaker than C band, we also consider it as a positive result. Positive shows that the concentration of SEM is above 1 ppb in the sample.
Negative: The presence of both clear bands in C zone and T zone. (T band is close to or stronger than C band.)
Invalid: No colored band appears in C zone.
The results are negative when the test card is applied to detect AOZ, AHD and AMOZ.
The kit can be stored at room temperature (2-30°C). The test kit is stable through the expiration date (18 months) marked on the foil pouch. DO NOT FREEZE. Do not store the test kit in direct sunlight.
-For best results, please strictly adhere to these instructions.
-All reagents must be at room temperature before running the assay.
-Do not remove test cassette from its pouch until immediately before use. Do not reuse the test kit.
-Do not use the test beyond its expiration date marked on the foil pouch.
-The components in this kit have been quality control tested as standard batch unit. Do not mix components from different lot numbers.
SEM Rapid Test is an useful tool offering a rapid and accurate testing in field screening, exceeding with its convenience. It provides a semi-quantitative method to detect the SEM above 1 ppb in tissue. If you want a quantitative result, please adopt other method such as ELISA/ HPLC in practice.
Contact Person: Ms. Anna Lee