Microflow LC-MS/MS Analysis of Monoclonal Antibody in Human Plasma at ng/mL Level with nSMOL™ Proteolysis

A highly sensitive quantitation of the therapeutic monoclonal antibody Trastuzumab using a combination of nSMOL proteolysis and the Nexera Mikros system is introduced. Using this microflow system, the lower limit of quantitation (LLOQ) was 0.00763 μg/mL which is higher than the LLOQ of 0.060 μg/mL when using a conventional semi-microflow LC/MS system (cited from Application News No. C145A), indicating a sensitivity 7.9 times higher. In addition, the analysis cycle time was 11 min compared to the 7 min when using a semi-microflow LC/MS system, showing that sensitivity can be improved without greatly compromising throughput. Quantitation of therapeutic monoclonal antibodies is possible with higher sensitivity by combining nSMOL proteolysis, which standardizes sample preparation for all antibodies, with a microflow LC/MS system featuring both high sensitivity and robustness.