Mass spectrometry

The Chemistry Department's mass spectrometry service has four spectrometers in service, operating mainly for the research groups within the department.

Kratos Concept 1H

Ionisation techniques available are EI, CI and FAB with the options of nominal mass spectra, high resolution spectra and accurate mass determinations by peak matching.

Some high energy collision MS/MS experiments can also be run by linked scanning, i.e. precursor-product ion, product-parent ion, constant mass loss and constant mass gain scans. There is also an electrospray source, which is limited to flow rates of approximately 10ul min-1 and used very rarely.

Micromass Quattro

This spectrometer is used with set methods based on expected mass. The ionisation source used is electrospray and spectra for both positive ions and negative ions are produced automatically. Unless specifically booked, the instrument is available 24 hours per day, 7 days per week. A simple demonstration of the logging-on procedure is all that is required for users to submit their own samples.

The instrument is also capable of low energy collision MS/MS experiments which must be run by the operator (Mick) and need to be discussed and booked beforehand. Similarly, LC/MS and LC/MS/MS work can be undertaken after suitable discussions. Single ion scanning and multiple reaction monitoring (MRM) are also available options.

Perkin-Elmer TurboMass GCMS

This spectrometer is used with set methods based on the type of sample and expected behaviour through a GC column.

Generally the ionisation is EI, however CI (both positive and negative) may be possible for selected samples. Prior booking and discussion is required for this as the instrument must be specifically set up for this work.

The chromatograms obtained may be quantified and spectra submitted to library searching. No MS/MS is possible, although single ion scanning may be utilised for greater selectivity.

Applied Biosciences Voyager DE-STR

This spectrometer is used by The Centre for Chemical Biology. Ionisation is by matrix-assisted laser desorption, and can be used in linear or reflectron mode. There is the facility to do post-source decay (PSD) experiments. The instrument can either be used manually or set to automatically scan any or all the spots on the sample plate.

Waters Acquity XEVO Q ToF

This is an UPLC-MS system using an electrospray ionisation time-of-flight mass spectrometer to determine exact masses within 3ppm or better. UPLC allows HPLC separations to be conducted in much shorter time spans and usually with smaller sample volumes.

Simple single compound determinations or more complex mixtures can be handled giving exact mass, MSMS and formula prediction. The only requirement is that the species is ionisable by electrospray.