Mass Spectrometry

Mass spectrometry in the Chemical Analysis Laboratory is supported by four spectrometers providing modern methods of mass analysis. The instruments include three systems from ThermoFisher Scientific, namely an Orbitrap XL, an ITQ1100 and a Delta V advantage; the fourth spectrometer is an SAI LaserToF.

Orbitrap XL

A state-of-the-art mass spectrometer capable of analysing highly complex mixtures. Samples can be introduced to the instrument via either direct infusion into the probe or via a chromatographic setup (TFS Accela) that enables resolution of the sample. Ionisation is via electrospray ionisation (ESI) or atmospheric pressure chemical ionisation (APCI); a nano-spray source is used for analysis of proteomic samples. The Orbitrap allows for complex workflows where accurate mass data is recorded along with MS/MS data. The acquisition of MS/MS data can be fully automated using a sophisticated data dependent setup.

ITQ 1100

An iontrap-based mass spectrometer that is coupled to a TFS Trace Ultra gas chromatography (GC) system. The GC is equipped to perform liquid analysis, head-space analysis of solid-phase micro extraction (SPME). Columns can be connected to the autosampling robot via either a split/splitless injection port or a programmed temperature vapourising port. The iontrap mass analyser covers the mass range from 50–1100 Da and can ionise the eluting compounds from the GC via either EI or CI methods. The system is equipped with a variable dampening gas option and a pulsed positive/ negative chemical ionisation switching option. MS/MS is also possible using the ITQ1100 system and fragmentation can be achieved using pulsed Q dissociation to give greater coverage of the mass range in such MS/MS experiments.

Delta V

The Delta V advantage is a stable isotope ratio mass spectrometer. The Delta V IRMS is designed to perform high precision measurements of isotope ratios of H/D, ¹³C/¹²C, ¹⁵N/¹⁴N, ¹⁸O/¹⁶O, ³⁴S/³²S, ³⁷Cl/³⁵Cl from a variety of materials. Prior to analysis by the mass spectrometer, the samples are transformed into pure gaseous substances: H₂, N₂, CO, CO₂ and SO₂. This is achieved by oxidation, reduction or high temperature conversion using different inlet and preparation systems for which the Delta V provides a flexible and open platform. The Delta V in the Chemical Analysis Laboratory is connected to a Flash EA 1112 HT with a smart EA function to enable auto-dilution and a GasBench II sample preparation device; these sample preparation devices are interfaced to the mass spectrometer via an intelligent interface – the Conflo IV.

SAI LaserToF

This instrument is capable of providing accurate molecular weight data for peptides and other natural macromolecules in addition to synthetic polymers such as polystyrene, polymethyl methacrylate and polyethylene glycol. The SAI LT3 LaserTof system features pulsed extraction; post source decay (PSD); a harmonic reflectron; a high mass detector (>500,000 Da) and neutral detection modes. The resolution in reflectron mode is >10,000 (FWHM) and >4,000 (FWHM) in linear mode both providing high sensitivity.