The Folic Acid ELISA Assay kit is a quantitative assay based on the principle of the enzyme linked immu nosorbent assay. A folic acid conjugate is bound on the surface of a microtiter plate. Folic acid containing samples or standards and an antibody directed against folic acid are given into the wells of the microtiter plate. Immobi lized and free folic acid compete for the antibody binding sites. After one hour incubation at room tem perature, the wells are washed with diluted washing solution to remove unbound material. A peroxidase conjugate against the antibody is given into the wells and after another hour incubation, the plate is washed again. Then a substrate solution is added and incubated for 20 minutes, resulting in the devel opment of a blue colour. The colour development is inhibited by the addition of a stop solution, and the colour turns yellow. The yellow colour is measured photometrically at 450 nm. The concentration of folic acid is indirectly proportional to the colour inten sity of the test sample. Sample Types: food products. Range: 4 - 400 ng/ml. Sensitivity: 2 ng/ml. Time: 2 hours ? Folates play an important role in the synthesis of nucleic acids and some amino acids and gained re cently increased interest because they belong to the group of antioxidative vitamins. In the last years the in fluence of folic acid supplementation to avoid abortion and dysraphism was a topic of research increasingly. Folic acid as the most stable representative of the group of folates is added to a broad range of food.