This project will develop novel analytical methods to increase the chemical information obtained by REIMS. This will be focused on fats and lipids which are important for human health and target food items such as oils, milks, and meats to develop a faster method for understanding their composition.
Mass spectrometry (MS) is a powerful analytical tool and has become a mainstay of scientific research across the life and chemical sciences. Nevertheless, MS can be restricted by the requirement for time-consuming sample processing, extraction, and chromatographic separation. The field of ambient ionisaton mass spectometry (AIMS) was established approximately 15 years ago with the foundational techniques of DART and DESI. There are now over 100 different AIMS methodologies, but all share the similarity that ion generation happens in an open atmosphere. This allows workflows with little to no sample preparation or extraction and which offer substantially higher throughput. They do, however, suffer from ion suppression and reduced analytical resolution as they are no longer coupled to a pre-ionisation chromatographic separation. This is a barrier to their wider adoption as they do not offer the same insight as traditional methods. This is particularly pronounced in lipid analysis. Lipids play important roles in biological systems, including in signalling and cellular membranes. They are structurally diverse and complex with different isomers having different biological functions. (Poly)unsaturated fatty acids are particularly important considering their health effects. Our main source is food, which means understanding different abundances is an important analytical need. Current methods rely on GC and LC-MS. AIMS methods, including REIMS, typically show excellent detection of fatty acids and phospholipids, but are unable to detect different isomers.
This project will develop novel REIMS workflows through the adaptation of methods for chemical modification and collision induced disassociation (CID) fragmentation. These methods have previously been implemented with LC-MS platforms but not with AIMS workflows. These would use diagnostic fragment ions to identify the position of the C=C double-bond and provide structural identification of unsaturated fatty acids and phospholipid fatty acyl chains. Importantly, this would be achieved through minimal sample preparation and analysis time to retain the analytical throughput benefits of REIMS. This project will develop novel REIMS methods for fatty acid and phospholipid analysis. It will utilise an existing REIMS set-up incorporating a CO2 laser for sample heating and evaporation and integrated with an XYZ gantry robot for automated and high-throughput analysis. The work will fall into four broad areas: 1) Development of REIMS method for C=C positioning in unsaturated fatty acids 2) Development of REIMS method for characterisation of phospholipid acyl chains 3) Testing of food items using developed methods 4) Pairing of developed methods with REIMS imaging.
Start Date: 1 October 2022
Duration: 3 years
How to apply: Applications must be submitted via https://dap.qub.ac.uk/portal/user/u_login.php
Skills/experience required: Experience in working with or knowledge of mass spectrometry, (bio)analytical chemistry.
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