A5038984873- Mass Spectrometry Techniques and Applications
- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Analytical chemistry methods development
- Ion-surface interactions and analysis
- Advanced Chemical Sensor Technologies
- Advanced Chemical Physics Studies
- Astrophysics and Star Formation Studies
- Forensic Fingerprint Detection Methods
- Molecular Spectroscopy and Structure
- Analytical Chemistry and Chromatography
- Forensic and Genetic Research
- Space Science and Extraterrestrial Life
- Spaceflight effects on biology
- Methane Hydrates and Related Phenomena
- Forensic Toxicology and Drug Analysis
- nanoparticles nucleation surface interactions
- Geomagnetism and Paleomagnetism Studies
- Zeolite Catalysis and Synthesis
- Thermal Radiation and Cooling Technologies
- Air Quality Monitoring and Forecasting
- Geochemistry and Geologic Mapping
- Clay minerals and soil interactions
- Analytical Chemistry and Sensors
Imperial College London
2020-2024
University of Sussex
2016-2021
National Physical Laboratory
2009-2018
Heriot-Watt University
2018
Brighton Hospital
2016-2017
Teddington Memorial Hospital
2016
University of Oxford
2009
Abstract The MAss Spectrometer for Planetary EXploration (MASPEX) is a high-mass-resolution, high-sensitivity, multi-bounce time-of-flight mass spectrometer (MBTOF) capable of measuring minor species with abundances sub-parts-per-million in Europa’s sputter-produced and radiolytically modified exosphere its oceanic plumes. goal the MASPEX-Europa investigation to determine, through in-situ measurement plume composition, whether conditions habitability exist or have existed on Europa. As...
Latent fingerprints provide a potential route to the secure, high throughput and non-invasive detection of drugs abuse.
Abstract Ambient mass spectrometry (ambient MS) is a powerful and rapidly growing new field that provides high sensitivity MS directly from surfaces at ambient pressure. There now rich evidence base in the published literature of success these methods for forensic analysis including: detection explosives nanogram levels; chemical composition counterfeit pharmaceutical tablets, drugs abuse biological liquids such as urine plasma; breath metabolites; imaging document verification fingerprint...
In desorption electrospray ionisation (DESI) the interaction between and surface is key to two important analytical parameters, spatial resolution sensitivity. We evaluate effect of solvent type, organic fraction with water, analyte solubility substrate wettability on DESI erosion diameter material transferral into useful ion signal. To do this five amino acids, glycine, alanine, valine, leucine phenylalanine are prepared as thin films three substrates, UV/ozone treated glass, glass...
Liquid Extraction Surface Analysis (LESA) is a new, high throughput tool for ambient mass spectrometry.
Organic matter in sediments is dominated by kerogen, a high molecular weight geomacromolecule. Kerogen can be subdivided into Types I to IV that provide paleoenvironmental and petroleum potential information. typing performed several chemical methods including elemental analysis (H/C O/C), FTIR pyrolysis-gas chromatography techniques. However, kerogens occur naturally within mineral matrices these influence the responses. We have examined effects of range minerals (namely kaolinite,...
A VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study for desorption electrospray ionization mass spectrometry (DESI MS) measurements has been conducted with the involvement of 20 laboratories from 10 countries. Participants were provided an analytical protocol two reference samples: a thin layer Rhodamine B double-sided adhesive tape, each separate glass slides. The studies comprised acquisition positive ion spectra in predetermined m/z ranges. No sample...
The icy moons of the outer Solar System display evidence subsurface liquid water and, therefore, potential habitability for life. Flybys Saturn's moon Enceladus by Cassini spacecraft have provided measurements material from plumes that suggest hydrothermal activity and presence organic matter. Jupiter's Europa may similar is target forthcoming Clipper mission carries a high mass resolution sensitivity spectrometer, called MAss Spectrometer Planetary EXploration (MASPEX), with capability...
Results are presented on the optimization and characterization of a plasma-assisted desorption ionization (PADI) source for ambient mass spectrometry. It is found that by optimizing geometry we can increase ion intensities valine tuning plasma power also select more fragmented or less spectrum. The temperature surface rises linearly with power: at 19 W it 71 °C 28 126 °C. To understand if changes in signal intensity related to thermal desorption, experiments using temperature-controlled...
Two ambient ionisation techniques, desorption electrospray (DESI) and plasma assisted (PADI), have been used to analyse personal care products (PCPs) on fixed fibroblast cell surfaces. The similarities differences between the two techniques for this type of analysis explored in various ways. Here, we show results DESI PADI individual PCP ingredients as well these complex creams model skin surfaces, with minimal sample preparation. Typically, organosiloxanes small molecules were detected from...
Plastics and microplastics are major hazards for the environment human health. Plastic materials in sedimentary record a marker modern anthropogenic activity. One environmental reservoir of plastics is soil. method to detect presence soil, thereby recognise its hazards, pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). Yet soils multicomponent mixtures any analytical artefacts generated will reduce our ability monitor plastics. We have studied Py-GC-MS responses polymers...
Ancient martian organic matter is likely to take the form of kerogen-like recalcitrant macromolecular (MOM), existing in close association with reactive mineral surfaces, especially iron oxides. Detecting and identifying a biological origin for MOM will therefore be utmost importance life-detection efforts at Mars. We show that Type I IV kerogens provide effective analogues putative abiological (meteoric) provenances, respectively. analyze pyrolytic breakdown products when these are mixed...
Plasma-based desorption/ionization sources are an important ionization technique for ambient surface analysis mass spectrometry. In this paper, we compare and contrast three competing plasma based sources: a radio-frequency (rf) needle, dielectric barrier jet, low-temperature probe. The composition of the their effectiveness at analyzing range pharmaceuticals polymers were assessed. Results show that background spectrum each source was dominated by air species, with rf needle producing...
This work presents a study of water mobility on interstellar dust grain analogues at temperatures as low 18 K. The indicates that forms pure domains rather than covering the entire grain, thereby leaving bare surfaces available which other molecules can adsorb well themselves providing for further adsorption from gas.
Evidence of liquid water is a primary indicator habitability on the icy moons in our outer solar system as well terrestrial planets such Mars. If water-containing environments host life, some its organic remains can be fossilized and preserved biosignatures. However, inorganic materials may also present water-assisted organic-inorganic reactions transform architecture biological remains. Our understanding fate these assisted by experimental simulations that monitor chemical changes occur...
Many different types of samples have been analyzed in the literature using plasma-based ambient mass spectrometry sources; however, comprehensive studies important parameters for analysis are only just beginning. Here, we investigate effect sample form and surface temperature on signal intensities plasma-assisted desorption ionization (PADI). The is very important, with powders all volatilities effectively analyzed. However, thin films at room a low plasma power, vapor pressure greater than...
The authors report on a modified micro-plasma assisted desorption/ionisation (PADI) device which creates plasma through the breakdown of ambient air rather than utilising an independent noble gas flow. This new micro-PADI is used as ion source for mass spectrometry to analyse species released from surfaces polytetrafluoroethylene, and generic ibuprofen paracetamol tablets remote activation surface by plasma. spectra these compare favourably those produced PADI constructed using earlier...
A systematic characterisation and optimisation of parameters a plasma-mediated ion source to achieve the best spatial resolution for MSI.
Life detection missions to the outer solar system are concentrating on icy moons of Jupiter and Saturn their inferred subsurface oceans. Access evidence habitability, possibly even life, is facilitated by ejection material in plumes outgassing fissures. Orbiting spacecraft can intersect plume or detect past sputtered remnants outgassed products analyze contents using instruments such as mass spectrometers. Hydrothermalism has been proposed for environments moons, organic remains any...
Abstract The most prevalent of the ambient mass spectrometries, desorption electrospray ionisation (DESI), which provides highly sensitive spectrometry from surfaces without constraint vacuum, is compared with secondary ion (SIMS). potential DESI has been demonstrated in a wide range application areas, including forensics, homeland security, counterfeit detection pharmaceuticals and biological analysis. As all techniques, there are some disadvantages: cannot generally desorb molecules that...
The first comparative study of the surface behavior four small aromatic molecules, benzene, toluene, p-xylene, and o-xylene, adsorbed on graphite at temperatures ≤30 K, is presented. Intermolecular interactions are shown to be important in determining growth molecules low (monolayer) exposures. Repulsive intermolecular dominate benzene toluene. By contrast, stronger with observed for xylene isomers, islanding o-xylene. Multilayer desorption energies increase size molecule, ranging from 45.5...
Strong interactions between 2-propanol and water ice cause marked changes in the crystallisation kinetics desorption of water.
We present a novel UV/visible reflection-absorption spectrometer for determining the refractive index, n, and thicknesses, d, of ice films. Knowledge index these films is particular relevance to astrochemical community, where they can be used model radiative transfer spectra various regions space. In order make models more accurate, values n need recorded under astronomically relevant conditions, that is, ultra-high vacuum (UHV) cryogenic cooling. Several design considerations were taken...