In-Situ Mass Spectrometry Analysis Under Ambient Conditions

Mass Spectrometry (MS) is an important analytical tool in the identification and quantification of a wide range of samples, primarily because of its speed, sensitivity, selectivity and versatility in analysing, gases, solids and liquids. MS is an interdisciplinary analytical tool, impacting many areas of science from physics, through chemistry, to biology. However MS is mainly limited to laboratory settings due to the high vacuum requirement needed for ion generation and processing. The main theme of this work is the development of ionisation methods that enable ion generation and processing under ambient conditions in the open air outside of the laboratory for in-situ applications. To that end, it is also important that ions are generated and processed with little or no extensive sample preparation steps required. In this work the development of two ambient ionisation methods: desorption atmospheric pressure chemical ionisation (DAPCI) and paper spray (PS) ionisation and their application for in-situ MS analysis is demonstrated. A DAPCI handheld ion source version based on DAPCI was developed to ignite a corona discharge in air and operates for up to 12 h continuously using only 12 V battery. Both DAPCI and PS ambient ionisation methods were implemented for in-situ MS analysis and were used to detect trace amounts (< ng) of different classes of chemical compounds (i.e hydrocarbons, explosives corrosion inhibitors and metaldehyde in waters samples); this was achieved rapidly (i.e. less than 1 minute) with little or no sample preparation in the open air. Both ambient ionisation methods (i.e., DAPCI and PS) were used with either a commercial instrument or with a custom miniature mass spectrometer to identify and characterize traces amounts of petroleum oil hydrocarbons and additives (e.g. quaternary ammonium corrosion inhibitors), and water pollutants (e.g. metaldehyde) with high sensitivity and selectivity. The handheld DAPCI and PS methods were also applied to the in-situ direct analysis of explosives. Good performance was achieved with the miniaturised instrument giving detection limits within an order of magnitude to those achieved using a benchtop commercial instrument. The results reported in this thesis should be of importance to those interested in ambient ionisation mass spectrometry, miniature mass spectrometry, in-situ MS analysis, oilfield chemical analysis, homeland and border security agencies and environmental monitoring

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons

A physical model of electromagnetic induction is developed which relates directly the forces between electrons in the transmitter and receiver windings of concentric coaxial finite coils in the near-field region. By applying the principle of superposition, the contributions from accelerating electrons in successive current loops are summed, allowing the peak-induced voltage in the receiver to be accurately predicted. Results show good agreement between theory and experiment for various receivers of different radii up to five times that of the transmitter. The limitations of the linear theory of electromagnetic induction are discussed in terms of the non-uniform current distribution caused by the skin effect. In particular, the explanation in terms of electromagnetic energy and Poynting’s theorem is contrasted with a more direct explanation based on variable filament induction across the conductor cross section. As the direct physical model developed herein deals only with forces between discrete current elements, it can be readily adapted to suit different coil geometries and is widely applicable in various fields of research such as near-field communications, antenna design, wireless power transfer, sensor applications and beyond

Consensus Based Networking of Distributed Virtual Environments

Distributed Virtual Environments (DVEs) are challenging to create as the goals of consistency and responsiveness become contradictory under increasing latency. DVEs have been considered as both distributed transactional databases and force-reflection systems. Both are good approaches, but they do have drawbacks. Transactional systems do not support Level 3 (L3) collaboration: manipulating the same degree-of-freedom at the same time. Force-reflection requires a client-server architecture and stabilisation techniques. With Consensus Based Networking (CBN), we suggest DVEs be considered as a distributed data-fusion problem. Many simulations run in parallel and exchange their states, with remote states integrated with continous authority. Over time the exchanges average out local differences, performing a distribued-average of a consistent, shared state. CBN aims to build simulations that are highly responsive, but consistent enough for use cases such as the piano-movers problem. CBN's support for heterogeneous nodes can transparently couple different input methods, avoid the requirement of determinism, and provide more options for personal control over the shared experience. Our work is early, however we demonstrate many successes, including L3 collaboration in room-scale VR, 1000's of interacting objects, complex configurations such as stacking, and transparent coupling of haptic devices. These have been shown before, but each with a different technique; CBN supports them all within a single, unified system

In-Situ Analysis of Essential Fragrant Oils Using a Portable Mass Spectrometer

A portable mass spectrometer was coupled to a direct inlet membrane (DIM) probe and applied to the direct analysis of active fragrant compounds (3-methylbutyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and ethyl methyl sulfide) in real time. These fragrant active compounds are commonly used in the formulation of flavours and fragrances. Results obtained show that the portable mass spectrometer with a direct membrane inlet can be used to detect traces of the active fragrant compounds in complex mixtures such as essential fragrant oils and this represents a novel in-situ analysis methodology. Limits of detection (LOD) in the sub-ppb range (< 2.5 pg) are demonstrated. Standard samples in the gaseous phase presented very good linearity with RSD % at 5 to 7 for the selected active fragrant compounds (i.e., isoamyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and methyl ethyl sulphide). The rise and fall times of the DIM probe are in the ranges from 15 to 31 seconds and 23 to 41 seconds, respectively, for the standard model compounds analysed. The identities of the fragrance active compounds in essential oil samples (i.e., banana, tangerine, papaya, and blueberry muffin) were first identified by comparison with a standard fragrance compounds mixture using their major fragment peaks, the NIST standard reference library, and gas chromatography mass spectrometry (GC-MS) analysis. No sample preparation is required for analysis using a portable mass spectrometer coupled to a DIM probe, so the cycle time from ambient air sampling to the acquisition of the results is at least 65 seconds

Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry

Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (<0.1 pg) has been demonstrated for the first time, without any sample preparation using paper spray mass spectrometry (PS-MS). The presence of Duomeen O in water samples was confirmed via tandem mass spectrometry using collision-induced dissociation and supported by exact mass measurement and reactive paper spray experiments using an LTQ Orbitrap Exactive instrument. Data shown herein indicate that paper spray ambient ionization can be readily used as a rapid and robust method for in situ direct analysis of polymanine corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar

Artificial Odour-Vision Syneasthesia via Olfactory Sensory Argumentation

The phenomenology of synaesthesia provides numerous cognitive benefits, which could be used towards augmenting interactive experiences with more refined multisensorial capabilities leading to more engaging and enriched experiences, better designs, and more transparent human-machine interfaces. In this study, we report a novel framework for the transformation of odours into the visual domain by applying the ideology from synaesthesia, to a low cost, portable, augmented reality/virtual reality system. The benefits of generating an artificial form of synesthesia are outlined and implemented using a custom made electronic nose to gather information about odour sources which is then sent to a mobile computing engine for characterisation, classification, and visualisation. The odours are visualised in the form of coloured 2D abstract shapes in real-time. Our results show that our affordable system has the potential to increase human odour discrimination comparable to that of natural syneasthesia highlighting the prospects for augmenting human-machine interfaces with an artificial form of this phenomenon

Quality of Service Impact on Edge Physics Simulations for VR

—Mobile HMDs must sacrifice compute performance to achieve ergonomic and power requirements for extended use. Consequently, applications must either reduce rendering and simulation complexity - along with the richness of the experience - or offload complexity to a server. Within the context of edge-computing, a popular way to do this is through render streaming. Render streaming has been demonstrated for desktops and consoles. It has also been explored for HMDs. However, the latency requirements of head tracking make this application much more challenging. While mobile GPUs are not yet as capable as their desktop counterparts, we note that they are becoming more powerful and efficient. With the hard requirements of VR, it is worth continuing to investigate what schemes could optimally balance load, latency and quality. We propose an alternative we call edge-physics: streaming at the scene-graph level from a simulation running on edge-resources, analogous to cluster rendering. Scene streaming is not only straightforward, but compute and bandwidth efficient. The most demanding loops run locally. Jobs that hit the power-wall of mobile CPUs are off-loaded, while improving GPUs are leveraged, maximising compute utilisation. In this paper we create a prototypical implementation and evaluate its potential in terms of fidelity, bandwidth and performance. We show that an effective system which maintains high consistencies on typical edge-links can be easily built, but that some traditional concepts are not applicable, and a better understanding of the perception of motion is required to evaluate such a system comprehensively