Affinity ligands such as antibodies are widely used in (bio)medical research for purifying proteins from complex biological samples. These ligands are generally immobilized onto solid supports which facilitate the separation of captured protein from sample matrix. Adsorptive microtiter plates are commonly used as solid supports prior to immunochemical detection (e.g. immunoassays) but hardly ever prior to LC-MS-based detection, and here we describe some applications, opportunities, and challenges of corresponding workflows.