Which Calibration Standards Can Be Used for Intact Protein Analysis on TripleTOF® and X500 Systemss?


日付: 12/14/2017
カテゴリー: Academia Omics , Pharma CRO , QTOF Systems

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For research use only. Not for use in diagnostic procedures.


Answer

The APCI calibrantsolution for the SCIEX X500B QTOF system and the mAb standard from Waters were compared. Calibration was tested using the APCI positive CDS calibrant solution (APCI Positive Calibration Solution) at 4 time bins and the monoclonal antibody (mAb) Waters standard (PN 186006552) at 80 time bins. After calibration, additional intact mAbs and ACDs were run on each system.

To achieve high levels of accuracy, instruments cannot be calibrated using a mAb. The sample composition is too variable – and even standard mAbs like the one obtained from Waters should not be used. In addition, variability across the charge state distribution due to slightly different desolvation efficiencies will affect the measured mass. Our recommendation is to use the TripleTOF® system or the X-Series QTOF calibration solutions and perform a CDS calibration as normal. Results for the X500 system are very linear across the entire mass range. In addition, the TripleTOF 5600/6600 system (PN 4460131) similarly shows very linear results above m/z 400, so there are no issues with extending calibration out to the mAb range.

The time bins do not affect calibration, so it is not necessary to match them with the sample method. The only method-level parameter that affects mass calibration is Stop Mass (because it affects pulser frequency). Q2 RF may have a *small* impact; but for the purpose of evaluating proteins, the Q2 RF will be at maximum in all cases so it will be the same for all methods.