Data 1 name: 20221221_500nulInflix250ngulNIST_180umcell-90minfocusing_2_externalpower_alwayson_omnitrap_ECD40ms_2 Description: A 4 µL mixture of infliximab (500ng/µL) and NISTmAb (250ng/µL) is aspirated by the Alias autosampler pI-trap system and transferred into the pI cell for 90-min, 2000V cIEF separation. After the focusing, the sample is slowly injected at 0.5 µL/min to Exploris 480 – omnitrap. Two experiments are set in the data acquisition method: 1. MS full scan with resolution 120 000. 2&3. MS/MS experiment performed by orbi-omnitrap. Two m/z ranges, 2481 ± 5 representing infliximab and 2471 ± 5 representing NISTmAb, respectively, are isolated and injected to the omnitrap, where ECD is executed with filament current 5.65A and irradiation time 40ms. Infliximab is the earlier peak at RT 12 -14 min, NISTmAb is the later peak 22 - 24 min. Data 2 name: 20221221_500nulInflix250ngulNIST_180umcell-90minfocusing_2_externalpower_alwayson_omnitrap_HCD30_1 Description: A 4 µL mixture of infliximab (500ng/µL) and NISTmAb (250ng/µL) is aspirated by the Alias autosampler pI-trap system and transferred into the pI cell for 90-min, 2000V cIEF separation. After the focusing, the sample is slowly injected at 0.5 µL/min to Exploris 480 – omnitrap. Three experiments are set in the data acquisition method: 1. MS full scan with resolution 120 000. 2&3. MS/MS experiment performed by orbi-omnitrap. Two m/z ranges, 2481 ± 5 representing infliximab and 2471 ± 5 representing NISTmAb, respectively, are isolated and get fragmented with HCD by orbitrap. HCD collision energy is set at 30%. Infliximab is the earlier peak at RT 12 -14 min, NISTmAb is the later peak 22 - 24 min. Data 3 name: 20221216_1ugulInflix100ngulNIST_180umcell-90minfocusing_2_externalpower_alwayson_omnitrap_EID50ms_2 Description: A 4 µL mixture of infliximab (1000ng/µL) and NISTmAb (100ng/µL) is aspirated by the Alias autosampler pI-trap system and transferred into the pI cell for 90-min, 2000V cIEF separation. After the focusing, the sample is slowly injected at 0.5 µL/min to Exploris 480 – omnitrap. Two experiments are set in the data acquisition method: 1. MS full scan with resolution 60 000. 2&3. MS/MS experiment performed by orbi-omnitrap. Two m/z ranges, 2481 ± 5 representing infliximab and 2471 ± 5 representing NISTmAb, respectively, are isolated and injected to the omnitrap, where ECD is executed with filament current 5.65A and irradiation time 40ms. 4. MS full scan with resolution 7500. Infliximab is the earlier peak at RT 12 -14 min, NISTmAb is the later peak 22 - 24 min.