Merck, C3041-50CAP, Carbonate-Bicarbonate Buffer

Sigma-Aldrich carbonate–bicarbonate buffer capsules provide a convenient way to prepare alkaline aqueous buffer for immunoassay development and other laboratory procedures requiring controlled basic conditions. One capsule dissolves in 100 mL of high-purity water to produce a carbonate–bicarbonate solution with a specified pH range of 9.3–9.9. The alkaline environment is particularly relevant to passive adsorption of compatible proteins and antibodies onto polystyrene ELISA surfaces, although coating performance depends on the biomolecule and plate chemistry. Capsule-based preparation reduces manual weighing of carbonate salts and helps keep the buffer recipe consistent across assay batches. The 50-capsule package enables preparation of multiple batches while minimizing the need to handle bulk powder for every run. This product is a dry buffer preparation format, not a bottle of ready-to-use liquid. Verify that the prepared buffer pH and sample compatibility meet the method's acceptance criteria before coating or analytical use.