MRMS aXelerate: LC Free Phenomics & Metabolomics
As biobanks and clinics open their doors to the promise of metabolic phenotyping for understanding population health, powerful analytical solutions capable of large-scale deployment are needed. The chemical complexity of clinical samples is traditionally measured by mass spectrometry hyphenation with GC or LC. While powerful, the performance of these approaches is dependent on the time invested in chromatographic separation, limiting sample throughput and narrowing the metabolic coverage to only those species amenable to the chromatographic method used. MRMS aXelerate is a rapid and innovative workflow utilizing Flow Injection Analysis (FIA) with ultra-high resolution magnetic resonance mass spectrometry (MRMS) achieving broad metabolic profiles in minutes. Metabolite identification is based on high mass accuracy (<500 ppb) and Isotopic Fine Structure (IFS).
MRMS is traditionally known as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS, or simply FTMS). The novel scimaX MRMS was launched at ASMS 2018 and is the highest performing commercial mass spectrometer to date, delivering resolving powers exceeding 20 Million and routine sub-ppm mass accuracy. Extremely high resolution allows for the detection of Isotopic Fine Structure. When observed, IFS enables an unknown’s molecular formula to be read directly from the mass spectrum. The combination of IFS, True Isotopic Pattern and sub-ppm mass accuracy allows for the confident molecular formula assignment of unknow species. The scimaX MRMS system is also the first to employ a conduction cooled magnet. Liquid Helium fills are no longer required, eliminating the need for weekly or monthly cryogen maintenance. This also reduces the footprint of the system, allowing it to fit in any standard laboratory. Another key feature of scimaX is the standard dual MALDI/ESI source that requires no hardware switching and changes in less than a second (a simple software click). This allows for both infusion workflows as well as MALDI workflows. The MALDI workflow will analyse a single 384-plate, with no cross contamination between samples.
High sample throughput is achieved for complex samples by removing the time-consuming LC step. While this may initially seem counterintuitive, MRMS can easily resolve 1,000’s of compounds in a single mass spectrum and is analogous to petroleum based MRMS workflows that can produce over 10,000 compounds in a single infusion run. With an approximate acquisition time of less than 2.5 minutes, this is almost an order of magnitude faster than a traditional “fast” 20-minute LC gradient and provides a high number of detected compounds.
The MRMS aXelerate workflow uses MetaboScape 4.0 to analyze the MRMS data. Metaboscape 4.0 extracts and combines all relevant information into a single table. It provides both supervised and un-supervised statistics, allowing researchers to quickly focus on relevant information. In brief, peaks belonging to the same molecular composition are de-isotoped, adducts are combined into features and subsequently aligned across all samples. As a first step in compound annotation, molecular formulae are assigned to all detected ions using the SmartFormula (SF) algorithm, applying metabolic-profiling specific filters to elements and element ratios. The SF algorithm incorporates a combination of IFS, TIP and ultra-high mass accuracy, allowing confident assignments at any intensity level. A list of expected metabolites (e.g. derived from HMDB) can also be applied for automatically assigning tentative identifications to extracted features. Annotation of metabolites via database matching incorporates both accurate mass and IFS information. The matching criteria is conveniently displayed in the “Annotation Quality Scoring” icon.
So whether Metabolomics, Phenomics or any other complex sample analysis, large scale sample evaluation is now possible as MRMS aXelerate utilizes the eXtreme resolving power of the scimaX MRMS and MetaboScape 4.0 to enable a powerful LC-free solution.
