Multiple reaction monitoring

Definition

Multiple reaction monitoring (MRM) is a targeted mass spectrometry technique used to quantify specific analytes in complex mixtures by monitoring predefined precursor-to-product ion transitions. This approach enhances sensitivity and specificity by focusing on particular ions, allowing for precise quantification even in challenging samples such as biological fluids or environmental matrices.

5 Must Know Facts For Your Next Test

1. MRM is widely used in pharmacokinetics to monitor drug levels and metabolites in biological samples like blood and urine.
2. The sensitivity of MRM makes it suitable for analyzing low-abundance compounds, which can be vital in clinical diagnostics.
3. In MRM, the use of isotopically labeled internal standards helps improve accuracy and reliability in quantifying the target analytes.
4. The technique can analyze multiple compounds simultaneously, increasing throughput and efficiency in analytical workflows.
5. MRM is instrumental in proteomics for quantifying proteins and peptides in complex biological samples, aiding in biomarker discovery and validation.

Review Questions

• How does multiple reaction monitoring enhance the sensitivity and specificity of mass spectrometry analyses?
  • Multiple reaction monitoring enhances sensitivity and specificity by focusing on specific precursor-to-product ion transitions for target analytes. By only measuring selected ion transitions, MRM minimizes background noise from other compounds in complex samples, making it easier to detect low-abundance analytes. This targeted approach is particularly beneficial in applications like pharmacokinetics or clinical diagnostics, where precise quantification is crucial.
• Compare and contrast multiple reaction monitoring with selected reaction monitoring, highlighting their applications.
  • Both multiple reaction monitoring (MRM) and selected reaction monitoring (SRM) focus on specific ion transitions in mass spectrometry. The key difference is that MRM monitors multiple precursor-to-product transitions simultaneously, allowing for the analysis of several analytes at once, while SRM typically focuses on a single transition. MRM is often used in high-throughput environments like drug development or proteomics, while SRM may be preferred for simpler analyses requiring high specificity.
• Evaluate the role of internal standards in enhancing the quantitative capabilities of multiple reaction monitoring.
  • Internal standards play a critical role in enhancing the quantitative capabilities of multiple reaction monitoring by compensating for variability during sample preparation and analysis. By using isotopically labeled analogs of the target analytes as internal standards, researchers can correct for potential losses or fluctuations that occur during the analytical process. This correction leads to more accurate quantification and improved reliability of results, making MRM a powerful tool in fields such as clinical diagnostics and drug monitoring.

Related terms

tandem mass spectrometry: A mass spectrometry technique that involves multiple stages of mass analysis, allowing for the identification and quantification of complex molecules by breaking them into smaller fragments.

selected reaction monitoring: A mass spectrometry method similar to MRM but focuses on a single ion transition for quantification, providing high specificity for certain analytes.

ionization: The process of converting molecules into ions, which is crucial for mass spectrometry as it allows analytes to be detected and analyzed based on their mass-to-charge ratios.