Direct quantification in bioanalytical LC-MS/MS using internal calibration via analyte/stable isotope ratio.

Area of Science:

• Analytical Chemistry
• Bioanalysis
• Mass Spectrometry

Background:

• Traditional bioanalysis relies on calibration curves, which can be time-consuming.
• Simplifying bioanalytical methods without sacrificing accuracy is a key goal.

Purpose of the Study:

• To investigate the feasibility of omitting calibration curves in bioanalysis.
• To evaluate a simplified quantification method termed 'internal calibration'.

Main Methods:

• Utilized mass spectrometry (MS) with a stable isotope labeled internal standard.
• Validated a bioanalytical LC-MS/MS method with and without traditional calibration curves.
• Assessed four key prerequisites for the internal calibration method.

Main Results:

• Internal calibration yielded results comparable in precision and accuracy to traditional methods.
• All four prerequisites for internal calibration were met.
• Validation data demonstrated excellent performance across the 0.010–30 micromol/L concentration range.

Conclusions:

• Internal calibration is a viable and simplified approach for bioanalysis.
• This method maintains analytical quality while reducing complexity.
• The study validates the internal calibration method for research compounds.