Liquid Chromatography-Mass Spectrometry
LC-MS is a versatile and highly sensitive analytical technique for the measurement of small molecular weight compounds in a diverse range of sample types. It uses a series of mass detection systems to provide both quantitative and qualitative analyses. Situated in the Centre for Analytical Bioscience within the School of Pharmacy our MS facilities are ideal for small molecule analysis (<2000m/z) and are complemented by a suite of UHPLC or specialised surface analysis interfaces (DESI, LESA) and software for data interpretation.
- Ultra-high-performance liquid chromatography (UHPLC) coupled to either high resolution-MS or QTrap MS.
- Accurate mass measurement (<5 ppm) for untargeted metabolomics and high resolution targeted quantitative analysis.
- Multiple reaction monitoring (MRM) and parallel reaction monitoring (PRM) for high sensitivity or specific quantitative analysis.
- Multi-stage MS and data-dependant MS fragmentation for structural elucidation and MS/MS identification.
- Ambient analysis of chemical compounds on biological/material surfaces using LESA-MS.
- Quantification of drug/drug metabolites, endogenous metabolites/lipids and contaminants in cells, microorganisms, plants, biofluids, tissues and environmental samples.
- Global metabolite profiling, metabolomics, biomarker discovery and surface analysis.
- Understanding the metabolic effects of biotic and/or abiotic perturbations on a biological system, for example drug-induced changes to intracellular metabolite pathways.
- Absolute quantification of a wide range of intra and extracellular metabolites using isotope-dillution mass spectrometry.
- Isotope-assisted metabolic pathway profiling.
How does LC-MS work?
Liquid chromatography (LC) provides a universal separation of chemical components in solution-based mixtures. It does so by the different affinities of the chemical compounds with a liquid mobile phase flowing through a stationary phase.
Mass spectrometry (MS) involves the ionisation of chemical species, followed by the detection of the mass-to-charge ratio (m/z) and intensity of the various ionised analytes. In the case of LC-MS this is following a chromatographic separation.
The huge complexity of the metabolites in biological systems has lead to LC-MS being utilised to reduce sample complexity by separating out the various sample components prior to their MS detection. Therefore, LC-MS is a powerful analytical technique not only for the quanitifcation of small biomolecules (metabolites) but also for the identification of unknown and known compounds in biological samples.
While traditionally a bulk analysis, modern technical adaptations usually pertaining to the ionisation method, allow LC-MS variants to be used as a powerful complimentary surface analytical tool.
1. Quantitative isotope dilution high-resolution mass spectrometry for bacterial metabolite determination
Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) methodology using multiple internal standards obtained from uniformly (U)-13C-labelled extract from Spirulina were used for the identification and quantification of the intracellular metabolites. This method enabled the simultaneous quantification and monitoring of 74 metabolites in C. autoethanogenum to study the effect of feeding different levels of carbon monoxide over 35 days on the central metabolism.
Sarah Schatschneider, Salah Abdelrazig, Laudina Safo, Anne M. Henstra, Thomas Millat, Dong-Hyun Kim, Klaus Winzer, Nigel P. Minton, David A. Barrett, Anal. Chem. 2018, 90, 7, 4470-4477.
2. Liquid Extraction Surface Analysis-Mass Spectrometry Using Superhydrophobic-Superhydrophilic Patterning
The use of the Droplet Microarray (DMA) provides a surface-assisted LESA-MS method delivering significant improvement of the surface extraction repeatability leading to the acquisition of more robust and higher quality data. Such a method shows potential to be used for LESA-MS for controlled and reproducible surface extraction and for acquisition of high quality, qualitative data in a high-throughput manner.
Meurs J, Alexander MR, Levkin PA, Widmaier S, Bunch J, Barrett DA and Kim D-H, Anal. Chem. 2018, 90, 10, 6001-6005
3. Plasma untargeted metabolomics and lipidomics of pre-eclamptic women reveals changes in the metabolome
LC-MS metabolic profiling of polar and apolar metabolites demonstrated that the metabolome undergoes substantial changes in pre-eclamptic women. Amongst the most discriminative metabolites were hydroxyhexacosanoic acid, diacylglycerols, glycerophosphoinositols, nicotinamide adenine dinucleotide metabolites, bile acids and products of amino acid metabolism.
Our LC-MS Facilities
QTRAP 6500+ and QTrap 4000 Quadrupole Linear Ion Trap LC-MS/MS
- Equipped with HPLC, UHPLC and SelexION Differential Mobility Separation Device.
- Quantitative and qualitative targeted metabolite profiling, and for ID confirmation. Used where sensitivity is required.
- Advanced MS scanning options and information dependant acquisition offer unique approaches to metabolite profiling and identification.
Thermo Fisher Exactive (Orbitrap technology) high resolution mass spectrometer
- Equipped with HPLC and UHLPC.
- Small molecules profiling and identification.
- Quantitative and qualitative measurements.
- Metabolomics and lipidomics with high resolution measurements.
Thermo Fisher QExactive (Hybrid quadrupole Orbitrap) high resolution mass spectrometer
- Equipped with UHPLC and Triversa NanoMate.
- Small molecules profiling and identification using accurate mass, fragmentation and local database of >300 authentic standards.
- Quantitative and qualitative measurements including high resolution targeted profiling.
- Metabolomics and lipidomics with high resolution measurements.
TriVersa NanoMate, Liquid Extraction Surface Analysis-Mass Spectrometry (LESA-MS)
- Surface extraction and analysis under ambient conditions.
- Advantages where UHV analysis may not be suitable; alternative to ToF-SIMS and MALDI.
- Coupled to QExactive MS and therefore, a high resolution and confidence in identification could be achieved using data dependant MS/MS.
Prosolia DESI-MS 2D Interface for Desorption Electrospray Surface Analysis (DESI)
- Surface MS analysis/imaging under ambient conditions.
- Advantages where UHV analysis may not be suitable. Alternative to ToF-SIMS and MALDI.
- Compound Discoverer 3.1 (Thermo Fisher Scientific)
- Progenesis QI (Nonlinear Dynamics)
- TraceFinder (Thermo Fisher Scientific)
- Analyst (Sciex)
- MultiQuant (Sciex)