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Updated: Jan 26, 2026
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Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics
Published on: October 13, 2020
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Multicenter Validation Study of Quantitative Imaging Mass Spectrometry
Jeremy A Barry1, Rima Ait-Belkacem2, William M Hardesty1
1Bioimaging , GlaxoSmithKline , 1250 S. Collegeville Road , Collegeville , Pennsylvania 19426 , United States.
Analytical Chemistry
|April 3, 2019
Summary
Quantitative imaging mass spectrometry (IMS) shows promising precision and accuracy for drug analysis in rat liver tissue. Stable-isotopically labeled standards improved quantification, especially in dilution series experiments.
Area of Science:
- Pharmacology
- Analytical Chemistry
- Biomedical Imaging
Background:
- Quantitative imaging mass spectrometry (IMS) is a powerful tool for analyzing drug distribution in tissues.
- Variability across sites, analysts, and instruments can hinder the reliability of IMS quantification.
- Standardization of protocols is crucial for reproducible IMS results.
Purpose of the Study:
- To evaluate sources of variability in quantitative IMS across different sites, analysts, and instruments.
- To assess the accuracy and precision of two common IMS quantification methods: mimetic tissue model and dilution series.
- To investigate the utility of stable-isotopically labeled (SIL) standards for improving IMS quantification and reducing image variability.
Main Methods:
- Rat liver samples perfused with clozapine were analyzed at three sites by three analysts using a standardized protocol.
- Clozapine and norclozapine were quantified using mimetic tissue and dilution series methods.
- Quantification accuracy and precision were compared against liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- The impact of SIL normalization on precision, accuracy, and image quality was assessed.
Main Results:
- Both quantitative IMS methods achieved low teens relative standard deviations and approximately 80% accuracy compared to LC-MS/MS.
- SIL normalization significantly improved accuracy and precision in the dilution series method.
- Optimal SIL normalization occurred when the analyte-to-internal standard intensity ratio was near one.
- SIL normalization showed less impact on the mimetic tissue model.
Conclusions:
- Quantitative IMS can achieve reliable drug quantification in rat liver tissue with standardized protocols.
- SIL normalization is a valuable tool for enhancing the accuracy and precision of IMS, particularly for the dilution series method.
- The effectiveness of SIL normalization is dependent on the analyte-to-internal standard ratio, limiting its universal application.
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