Description
Principle of the assay: Vanillylmandelic acid ELISA kit applies the competitive enzyme immunoassay technique utilizing a monoclonal anti-Vanillylmandelic acid antibody and an Vanillylmandelic acid-HRP conjugate. The assay sample and buffer are incubated together with Vanillylmandelic acid-HRP conjugate in pre-coated plate for one hour. After the incubation period, the wells are decanted and washed five times. The wells are then incubated with a substrate for HRP enzyme. The product of the enzyme-substrate reaction forms a blue colored complex. Finally, a stop solution is added to stop the reaction, which will then turn the solution yellow. The intensity of color is measured spectrophotometrically at 450nm in a microplate reader. The intensity of the color is inversely proportional to the Vanillylmandelic acid concentration since Vanillylmandelic acid from samples and Vanillylmandelic acid-HRP conjugate compete for the anti-Vanillylmandelic acid antibody binding site. Since the number of sites is limited, as more sites are occupied by Vanillylmandelic acid from the sample, fewer sites are left to bind Vanillylmandelic acid-HRP conjugate. A standard curve is plotted relating the intensity of the color (O.D.) to the concentration of standards. The Vanillylmandelic acid concentration in each sample is interpolated from this standard curve