Standardization via Post Column Infusion-A Novel and Convenient Quantification Approach for LC-MS/MS

Area of Science:

• Analytical Chemistry
• Biomedical Science
• Mass Spectrometry

Background:

• Mass spectrometry (MS) is crucial in diagnostics, forensics, and environmental analysis.
• Stable isotope-labeled internal standards (SIL-IS) are the gold standard for MS quantification.
• Challenges arise when SIL-IS are unavailable, costly, or difficult to synthesize.

Purpose of the Study:

• To introduce and validate a novel, economical quantification method: quantification via post column infusion (PCI).
• To demonstrate the application of PCI for tacrolimus measurement in whole blood using LC-MS/MS.
• To provide a convenient approach for correcting matrix effects in MS analysis.

Main Methods:

• Development and validation of a quantification via post column infusion (PCI) method.
• Application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for tacrolimus analysis.
• Comparison of PCI quantification with conventional internal standard (IS) quantification using patient samples.

Main Results:

• PCI method validation met European Medicine Agency (EMA) guidelines, with CV and bias below 15%.
• PCI quantification of tacrolimus in whole blood showed strong agreement with conventional IS quantification (r = 0.9532).
• The study demonstrated a more convenient method for correcting matrix effects compared to existing PCI techniques.

Conclusions:

• Quantification via post column infusion (PCI) is a reliable and affordable alternative for MS quantification, especially when SIL-IS are inaccessible.
• The developed PCI technique expands quantification options in MS and offers practical solutions for bioanalytical method development.
• This study provides guidance for incorporating PCI into existing or new LC-MS methods, enhancing analytical capabilities.