Antibody–drug conjugates (ADCs) are promising biopharmaceuticals. They combine the high selectivity and affinity to cancer cells with the toxicity of chemotherapeutics in one molecule. ADCs consist of a monoclonal antibody covalently bound by a linker to a highly potent cytotoxic drug. ADC-surrogates contain a nontoxic payload with similar structure and physiochemical properties as the toxic payload of an ADC. Therefore, they can be used as models to develop suitable purification processes or analytical methods. The ADC-surrogate in this work consists…