We have a Thermo Q-Exactive Plus Orbitrap mass spectrometer, obtained as part of a €513,000 EPSRC grant awarded to Dr Melanie Bailey.
The grant (EP/P001440/1) will explore the combination of ion beam analysis (IBA) and direct analyte probed nano-extraction mass spectrometry (DAPNe-MS) for sub-micron scale molecular speciation and quantification.
IBA will provide with elemental information as well as potential regions of interest that can be probed using DAPNe-MS, providing complementary molecular information.
Direct analyte probed nano-extraction mass spectrometry (DAPNe-MS)
DAPNe is an extraction technique that uses a nano-manipulator to position a capillary (with a 1 µm internal diameter) on the region of interest.
With the aid of a cell pressure injector, solvent is injected onto the sample for extraction (with an achievable 100 µm spot size, measured using a Nikon AZ100 microscope) and then re-aspirated back into the capillary.
The capillary containing the extracted material is then placed on a Nanospray Flex™ Ion Source for mass spectrometry analysis. DAPNe has been used to extract spiked drugs in tissue homogenates and is being developed for other applications such as the analysis of single cells, hair and paint.
Paper spray-mass spectrometry (PS-MS)
Paper spray-mass spectrometry (PS-MS) was developed at Purdue University in 2010. It uses a triangular piece of paper (chromatography paper, most commonly) to collect the sample. The application of a voltage (2-5 kV) and a solvent causes the extraction of the analytes from the paper and into the mass spectrometer.
The technique has found application in dried blood spots analysis and more recently, in drug testing using fingerprint sample. The technique has also shown promising results for explosives detection, with excellent sensitivity (low pg) and with very high sample throughput (30 seconds per sample).
Q-Exactive Plus Orbitrap
The Q-Exactive Plus Orbitrap mass spectrometer available in our centre offers excellent sensitivity and mass resolution (280,000 at m/z 400).
Several different ionisation sources are available to be coupled with the instrumentation.
Liquid chromatography-mass spectrometry (LC-MS)
The mass spectrometry facility at the Surrey Ion Beam Centre also includes liquid chromatography-mass spectrometry (LC-MS) facility.
The LC instrument available is comprised of a Thermo Ultimate™ 3000 UHPLC. Materials extracted using DAPNe-MS can be analysed using LC-MS for enhanced sensitivity and selectivity. Areas of research include proteomics, cell contents and drug testing.