The domestic and imported sub-package original elisa kits sold by Shanghai Jinma Biotechnology Co., Ltd. have all been certified by professionals. You can get the experiment after you get it. The quality is reliable and the results are accurate and stable.
1, the choice of kit
At present, there are many kinds of kits for enzyme-linked immunoassay, which are imported from abroad and developed and produced by ourselves. How to select a kit that meets the detection requirements and is inexpensive in many brands is a problem. According to the use of these kits, I found in the actual test that the following indicators are generally listed in the kit instructions: minimum detection limit; recovery rate; cross-reaction rate; standard curve map and data, the standard curve consists of at least 5 concentrations; The IC50 measured value and the number of deformation curve points are comparative specifications and can be selected.
2. Determination of the cut-off
The threshold value is first determined when actually using the enzyme-linked immunosorbent assay. By comparing the test results with the critical values, it can be determined that the sample is negative or suspicious. For banned drugs, the critical value of the test method is the limit of quantitation, which is the lowest limit of quantitation that can be achieved with existing accepted instrumental tests. For drugs with the highest residue limit (MRL), the cut-off value of the test method was 20 samples of the MRL concentration added and the mean of the three measurements was subtracted by 1.64 standard deviations. If the test result is less than the critical value is negative, greater than or equal to the critical value or the standard is suspicious, it needs to be confirmed by confirmatory method.
3. The detection limit can be added to each of the upper and lower concentrations of MRL and MRL.
When using the enzyme-linked immunosorbent assay in each laboratory, the detection limits of the respective laboratories should be checked. The limit of detection was the mean of 20 blank samples plus 3 standard deviations. If the detection limit obtained after the standard operation is greater than the critical value, the background interference of the kit is large, and the sensitivity of the kit cannot meet the detection requirements. The kit manufacturer should be contacted or discarded without using another kit.
4, enzyme-linked immunoassay method verification
When using the enzyme-linked immunosorbent assay to detect samples, the method should be verified. Mainly determine the following:
(1) Determination of the standard curve, the standard curve consists of at least 5 concentrations, and the number of measurements is not less than 5 times to determine the working concentration range and the IC50 range. Generally, the critical value is near IC50, and the detection sensitivity is high.
(2) Determination of sample detection limit.
(3) Sample addition recovery experiment. For the banned drugs, a limit of quantitation and a limit of 2 times the limit can be added. For drugs with the highest residue limit (MRL), one concentration above and below the MRL and MRL can be added.
Accuracy: If the recovery rate is greater than 40%, it meets the requirements of the corresponding testing standards. Precision: The intra-assay coefficient of variation has a coefficient of variation of less than or equal to 25% between each batch of parallel samples and less than or equal to 30% for banned drugs. The inter-assay coefficient of variation has a coefficient of variation of less than or equal to 30% for all samples and less than or equal to 40% for banned drugs.
To meet the above accuracy and precision requirements, it is indicated that the enzyme-linked immunosorbent assay is feasible and can be used to detect drug residues.
5, other
(1) For a kit that can be used for multi-residue detection, a drug having a low cross-reaction rate is positively added to measure a cut-off.
(2) The following tests should be included in the actual test: at least two standard curves, two negative controls, two positive cut-off controls, and two parallel samples to be tested. After the test results come out, the shape of the standard curve (according to the test requirement is S-shaped), whether the IC50 is close to the critical value and the recovery rate of the positive sample, and the parallel state of the sample can determine whether the test is reliable.
All ELISA kits of Shanghai Jinma Biotech can be used for free testing. The whole process of ELISA experimental technology guidance, free of charge to do experiments, to ensure that pre-sale, sale, after-sales consistently provide the most dedicated service, both new and old customers can enjoy Discount service.
Product categories of Disc Stylus Pen, We are the specialized manufacturer of Stylus Pen from China. Disc Stylus Pen no need to charge, you can use it directly, it is universal, it is compatible with all brands capacitive touch screens, such as Apple, Huawei, Samsung, Xiaomi, Microsoft, Google Chrome, ect. OEM / ODM are welcome, looking forward to our cooperation.
Disc Stylus Pen,Digital Stylus Pen,Cute Ballpoint Pen,2 In 1 Stylus Pencil
Shenzhen Ruidian Technology CO., Ltd , https://www.wisonens.com