Principle of Assay
Chloramphenicol Strip Test Kit (A327189) uses a competitive colloidal gold based format. The milk sample (200 µl) is added to a clear plastic reaction vessel, and used to resuspend the lyophilized reagents to a uniform pink color in the bottom of the microtiter wells. The milk is incubated briefly (5 min) to allow the Chloramphenicol binding proteins on the gold particles to engage with any antibiotic present in the milk. The test strip is then inserted into the sample well with the arrows pointing downward initiating capillary flow up the strip. Any gold particles that are not complexed with antibiotics present in the milk will bind to the test line, forming a signal (red line) at that position. Each test strip is imprinted with a Test line (T) and a Control line (C) at the top. If the binding protein on the gold particle has engaged with the Chloramphenicol residues present in the milk sample, the gold particle will flow past the test line and reach the C-line. For visual interpretation of the test results, a test line signal intensity that is stronger than the signal at the C-line indicates a negative result. Signal at the test line which is equal or less intense compared to the C-line indicates the presence of the corresponding Chloramphenicol in the milk. The greater the reduction in signal intensity at the test line, the greater the concentration of Chloramphenicol residues present in the milk.
