Abstract: A method is provided for determining in a medium the presence or amount of an analyte which is capable of binding to a ligand partner to form a ligand complex, which method comprises: (a) contacting the medium with either: (i) a ligand partner conjugated with an enzyme being capable of catalysing a reaction, or one or more reactions in a cascade thereof, to produce hydrogen peroxide, or (ii) a ligand partner and either a competing analyte or an analog of said analyte, a competing analyte or analyte analog being capable of forming a ligand complex with the ligand partner and the competing analyte or analyte analog being conjugated with an enzyme capable of catalysing a reaction, or one or more reactions in a cascade thereof, to produce hydrogen peroxide, (b) optionally separating complexed and uncomplexed enzyme conjugates, (c) causing or allowing the reaction or cascade of reactions to occur to produce hydrogen peroxide by contacting the complexed or uncomplexed enzyme conjugate with a corresponding enzyme su

Abstract: A method for allowing authentification of a bulk liquid e.g. petrol or another mineral oil based product, comprises introducing into the liquid a small amount of a chemiluminescent substance. Samples for authentification are subjected to the conditions required to trigger the chemiluminescent reaction and monitored for chemiluminescent emission.