Biotin conjugates can be detected by horseradish peroxidase, alkaline phosphatase substrates or anti biotin conjugated antibodies. Avidin and Streptavidin bind to the small biotin and are couple to HRP or AP for ELISA. To break the streptavidin Biotin bond we suggest to use a 6 molar guanidine HCl solution with acidity of pH 1.6.