Medicago AB Products Are Available Worldwide. For Research Use Only. This Protein L Ligand Leakage ELISA Kit has been designed to detect and quantify Protein L in Immunoglobulin (Ig) or Ig-fragment containing solutions. It is a sandwich ELISA with microtiter strips coated with an affinity purified anti-Protein L IgY-antibody. In this assay, the samples are boiled to separate the Ig/Ig-fragments from the Protein L in the solution, centrifuged, and incubated in the strip wells. The bound Protein L is then detected by adding a horseradish peroxidase (HRP)-conjugated anti-Protein L IgY antibody. Substrate is added to induce a colour change which is proportional to the amount of bound Protein L from the sample. The colour change is quantified spectrophotometrically at 450 nm by using a plate reader. The amount of protein L in the sample is determined by using a standard curve prepared in a reference sample. The reference sample should have the same concentration of Ig or Ig-fragments and preferably the same buffer composition as the elution samples from the Protein L affinity chromatography medium. However, it should be prepared using another purification strategy, e.g. ion exchange chromatography. Once a reference sample is created it can be aliquoted and used for several different protein L ELISA assays.