Determination of tetrahydrocannabinolic acid—carrier protein conjugate by matrix‐assisted laser desorption/ionization mass spectrometry and antibody formation

In order to form the monoclonal antibody against tetrahydrocannabinolic acid (THCA), THCA was coupled with bovine serum albumin (BSA) or human serum albumin (HSA) using β‐alanine as a linker or without β‐alanine to produce individual antigen conjugates. The number of haptens contained in the antigen conjugates was determined by matrix‐assisted laser desorption ionization mass spectrometry using BSA or HSA as an internal standard. The formation of monoclonal antibody is also discussed.