Understand the rationale behind the Q-TOF LC/MS that stably sustains sub-ppm mass accuracy.

High-resolution, accurate-mass (HRAM) mass spectrometers (MS) are a class of MS instrumentation with capability to resolve complex sample matrix and to allow identification of compounds by measuring their accurate masses.

In particular, those coupled to liquid chromatograph (HRAM LC/MS) have been used extensively for structural elucidation of unknown compounds primarily in chemical industry (impurity analysis) and biological researches (proteomics, metabolomics, lipidomics), but also increasingly in forensic science, food safety and environmental testing. Given the recent reduction of instrumentational cost, it will not take many more years until HRAM analysis becomes a versatile tool for all industries and researches.

The key performance attribute underlying all application fields is mass measurement accuracy (MMA) as it affords molecular specificity and reduction of false positive results. MMA is given in the specification of HRAM instruments in parts-per-million (ppm), frequently stating a result of a set of representative measurements e.g. “<1 ppm RMS”. However, this by itself does not convey how repeatably and reproducibly this MMA can be achieved.

The webinar describes various metrics that are relevant to statistical interpretation of MMA, which explain why mass resolution of 30,000 is more than sufficient for mass measurement at sub-ppm accuracy. Using the Shimadzu LCMS-9030 quadrupole time-of-flight MS, the rationale and strength of instrument stability for consistently achieving sub-ppm MMA has been demonstrated in small molecules.

Learning objectives:

Discuss how various parameters affect the accuracy of mass measurement
Demonstration of mass drift caused by temperature change
Learn how to assess whether a HRAM MS is practically capable of measuring at sub-ppm mass accuracy

Presenter: Atsuhiko (Ash) Toyama, PhD (MS Application Specialist, Analytical & Measuring Instruments Division, Shimadzu Corporation)

Ash Toyama has 10 years of proteomics research experience. His areas of expertise include not only proteomics but also quantitative mass spectrometry with particular focus on bioanalysis, metabolomics and endocrinology. At Shimadzu Corporation he played roles in academic research collaborations, application development and specification development of mass spectrometers. Ash holds a Master of Science degree in Biochemistry from University of Cambridge, UK, and was granted a Ph.D. degree in Biological Sciences from University of Tokyo for his research on clinical proteomics.