Antibody drug conjugates (ADCs) are potent and specific biopharmaceuticals. These proteins are typically analyzed using costly immunoassay methods, which do not have the selectivity to accurately quantify the ADC alone. HPLC-MS/MS analysis of the digested antibody is an alternative approach that provides better selectivity with less method development and cost when compared to magnetic bead immunoassay analysis. Additionally, coupling the mass spectrometer with a microflow LC platform (MFLC) results in a significant increase in the analyte signal. In this poster we describe an accurate, precise, cost effective extraction and MFLC-MS/MS analysis of the ADC SigmaMAb that can be applied to the extraction and analysis of other ADCs