MSACL 2016 US Abstract

Compound Specific Tuning

Imir Metushi (Presenter)
UC San Diego Health

Bio: Imir finished his BS in Chemistry from York University (Toronto, Canada) specializing in analytical chemistry. He then went to pursue a Ph.D in Pharmacology at the University of Toronto where he developed an interest in biomarker development for adverse drug reactions (ADRs). He did a one year post doc at the La Jolla Institute for Allergy and Immunology where he worked on the development of immunoassays used to prescreen for drugs that could have an HLA-linked ADR. He has 11 first author publications in high quality journals and has given several oral presentations in meetings such as: Society of Toxicology and Gordon Conference on Drug Metabolism. His interests are in biomarker discovery as well as performing mass spectrometry applications utilized in the toxicology laboratory. He is currently a Clinical Chemistry Fellow at UCSD.

Authorship: Imir G. Metushi
UC San Diego Health

Short Abstract

Compound specific tuning is essential in order to develop a quantitative LC-MS/MS based multiple reaction monitoring assay. This overview will focus on compound specific tuning and introduces basic concepts to help novice users understand what it means when your instrument representative says “We need to tune the mass spectrometer for your compound”.

Long Abstract

Commonly, mass spectrometers in the clinical laboratory quantify analytes by using multiple reaction monitoring (MRM). However, this requires that the investigator set up specific transitions for the analyte of interest which are based on the precursor ion. In order to achieve highest sensitivity, it is important to tune the mass spectrometer for the particular analyte of interest. This session uses diagrams, images and videos to demonstrate how compound specific tuning is applied to develop a MRM assay. Videos captured from infusion of standards will be used to demonstrate how a full scan spectrum is obtained and how to optimize parameters to maximize sensitivity for the parent ion. Compound specific examples will be given regarding optimizing tuning parameters such as desolvation gas, desolvation temperature, capillary voltage and cone voltage. The importance of duty cycle when setting up a MRM method will be discussed and examples will be given as to what happens to duty cycle if you choose to increase the number of compounds being monitored. Compound specific tuning is slightly different depending on the instrument being used, but the basic ideas covered in this session apply to most triple quadrupole based platforms.

By the end of the session users should be able to:

1. Describe basics of multiple reaction monitoring.

2. Define duty cycle.

3. Select optimal precursor ion.

4. Describe the effect of cone voltage, desolvation gas, desolvation temperature, and capillary voltage on sensitivity of precursor ions.

References & Acknowledgements:

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