Selected Reaction Monitoring

Definition

Selected Reaction Monitoring (SRM) is a mass spectrometry technique used to quantify specific analytes in complex mixtures by monitoring the transitions of selected ions. It enhances sensitivity and specificity by focusing on predefined precursor and product ions, making it particularly useful in applications like proteomics, metabolomics, and drug testing.

5 Must Know Facts For Your Next Test

1. SRM is often referred to as Multiple Reaction Monitoring (MRM) in the context of quantifying multiple analytes simultaneously.
2. The technique requires prior knowledge of the specific ions of interest, which makes method development crucial for accurate measurements.
3. In proteomics, SRM is used to quantify proteins by measuring transitions between peptide precursor ions and their corresponding product ions.
4. SRM offers high sensitivity and specificity compared to other quantitative methods, making it ideal for biomarker validation studies.
5. The technique can be applied in various fields including clinical diagnostics, environmental monitoring, and food safety assessments.

Review Questions

• How does Selected Reaction Monitoring enhance the analysis of complex biological samples compared to traditional mass spectrometry techniques?
  • Selected Reaction Monitoring enhances the analysis of complex biological samples by allowing researchers to focus on specific ions related to target analytes. This focused approach increases both sensitivity and specificity, enabling the detection of low-abundance compounds that may be overlooked in traditional methods. By monitoring predetermined precursor and product ion transitions, SRM provides more reliable quantification and is particularly valuable in fields like proteomics.
• Discuss the role of precursor ions in Selected Reaction Monitoring and how they impact the overall sensitivity of the technique.
  • Precursor ions are critical in Selected Reaction Monitoring as they are the initial ions selected for fragmentation in the mass spectrometer. The choice of precursor ions directly affects the sensitivity of the analysis; selecting the most abundant or stable precursor ions can lead to better signal intensity for downstream product ion detection. This careful selection ensures that even trace levels of target analytes can be quantified effectively.
• Evaluate how Selected Reaction Monitoring can be utilized in biomarker discovery and validation in clinical applications.
  • Selected Reaction Monitoring is a powerful tool for biomarker discovery and validation due to its high specificity and ability to quantify multiple targets simultaneously. In clinical applications, SRM allows researchers to measure proteins or metabolites associated with diseases at low concentrations, thus aiding in early diagnosis and treatment monitoring. The rigorous method development required for SRM ensures that results are reproducible and reliable, which is essential for translating research findings into clinical practice.

Related terms

Tandem Mass Spectrometry: A mass spectrometry technique that involves multiple stages of mass analysis, allowing for the identification and quantification of compounds based on their mass-to-charge ratios.

Precursor Ion: An ion that is selected for fragmentation in tandem mass spectrometry, which generates product ions for analysis.

Targeted Analysis: An analytical approach that focuses on the detection and quantification of specific compounds within a sample, as opposed to untargeted methods that analyze all components.