Comparison of different linear calibration approaches for LC-MS bioanalysis

Area of Science:

• Analytical Chemistry
• Bioanalysis
• Mass Spectrometry

Background:

• Linear calibration is crucial in LC-MS bioanalysis, with various approaches regarding concentration levels and replicates.
• Direct experimental comparisons of these calibration strategies are infrequent.
• Optimizing calibration methods is essential for accuracy, efficiency, and cost-effectiveness.

Purpose of the Study:

• To compare different linear calibration approaches, including novel ones, using simulations and experimental data.
• To evaluate the accuracy, robustness, and efficiency of two-concentration calibration versus multi-concentration methods.
• To determine the acceptable limits of non-linearity in linear calibration and propose practical implementation strategies.

Main Methods:

• Simulations and experimental validation were employed to compare calibration approaches.
• Accuracy and robustness of two-concentration (not forced through zero) versus multi-concentration calibration were assessed.
• A partially duplicate-standard approach was proposed to mitigate variations and batch failures.

Main Results:

• Two-concentration linear calibration demonstrated accuracy comparable or superior to multi-concentration methods.
• Extrapolation of linear curves to known linearity regions was found to be acceptable.
• The proposed partially duplicate-standard approach offers benefits of duplicate standards with cost and time savings.

Conclusions:

• Two-concentration linear calibration is a viable, accurate, robust, and cost-effective alternative for LC-MS bioanalysis.
• The study provides practical recommendations for implementing two-concentration calibration in regulated environments.
• Addressing concerns about linearity assessment with limited data points is key for adoption.