Synopsis

Abstract

Comprehensive structural characterisation of complex lipids, such as Glycerophospholipids (GPEs) by tandem mass spectrometry (MS/MS) continues to present a considerable challenge. Although there have been a number of studies which have used high-resolution mass spectrometry with various fragmentation methods, detailed structural and spatial distribution of these complex lipids still remains relatively unknown. Isomeric and isobaric species have also created immense difficulty in the elucidation and identification of these lipid components, and conventional dissociation methods do not generate fragmentation that permit the isomeric discrimination relative to the position of the double bonds on the acyl chains and the branching points on the glycerol backbone. In this investigation, direct infusion by nano-electrospray ionisation tandem-in-time MS/MS with collisionally-activated/induced dissociation (CAD/CID), electron induced dissociation (EID) and infrared multiphoton dissociation (IRMPD) were used for the detailed structural characterisation of L-α-Phosphatidylethanolamine, dioleoyl (GPEtn). This method enabled site-specific localisation of the double bonds on the acyl chains to be determined and provided sn-positional information of the di-acyl branching point on the glycerol backbone.

Abstract

Solution-state proton nuclear magnetic resonance spectroscopy (NMR) is a highly sensitive method used for the elucidation of various organic complexes, such as D-(+)-Glucose which undergoes anomerisation in solution. However, spectral overlapping from multiple proton (¹H) resonances in 1D NMR continues to present a considerable challenge when analyzing such complex mixtures, making it difficult to accurately assign the chemical shifts (δ/ppm) and J-couplings (²J and ³J_H-H) values to the associated spins. In this investigation a 1D-selective total correlation spectroscopy (sel-TOCSY) with a single Gaussian (π) pulse and decoupling in the presence of scalar interactions (DIPSI-2) mixing sequence was used in conjunction with 1D ¹H-NMR, 2D-hetero nuclear single quantum coherence spectroscopy (HSQC) (¹³C-¹H) and 2D-correlation spectroscopy (COSY) (¹H-¹H) to determine the molecular connectivities and enable a complete assignment of the overlapped proton resonances within α- and β-D-(+)-Glucose. Implementation of DIPSI-2 ‘spin-lock’ further provided an indication of the experimental cross-peak (I_2z) intensities and magnetization transfer within the D-(+)-Glucose spin-network relative to the TOCSY mixing time (τ_mix) between 10-100 ms. The experimental pulse sequence, internal Hamiltonian and spin system parameters were then compiled using a scripting interface (tcl), where the cross-peak intensities were simulated using a simulation package for solid-state NMR spectroscopy (SIMPSON), that works on the exploitation of the matrix-matrix multiplications and the numerical integration of the Liouville-von- Neumann equation, providing a comparable understanding of the magnetization transfer efficiency between J-coupled spins within α- and β-D-(+)-Glucose.

Code

SIMPSON 1D-TOCSY Code Available at

MAS-CDT MSc Mini-Project Groups

Project 1: FT-ICR MS Group (Department of Chemistry)

Project 2: Solid-State NMR Group (Department of Physics)

Academic Background

PhD in Molecular Analytical Science – University of Warwick (2020-Current)

MSc in Molecular Analytical Science - University of Warwick (2018-2020)

MSc (Distinction) in Analytical Science - University of Bradford (2015-2017)

BSc (Hons) (2.i) in Environmental Science with Chemistry - University of Bradford (2010-2014)

Previous BSc and MSc Projects

University of Bradford MSc Dissertation: Interactions of Organic Molecules and Ceramic Clays: Method Development for the Utilisation of Direct Insertion Probe-Mass Spectrometry and Dispersive Confocal Raman Spectroscopy

Supervised by Dr Ben Stern and Dr Richard Telford

University of Bradford BSc Dissertation: Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Top Soil by means of Gas Chromatography-Mass Spectrometry

Supervised by Dr Ben Stern and Professor Carl Heron (British Museum)

Professional Experience and Background

HPLC and Mass Spectrometry Laboratory Technician in Environmental Fate and Metabolism at Smithers Viscient (ESG) , Harrogate, North Yorkshire, United Kingdom, 2018.

Student Chemist- Light Isotope Laboratory, University of Bradford, Department of Archeological and Environmental Science, United Kingdom, 2014.

Student Biomedical Laboratory Technician- University of Leeds, School of Biomedical Science, United Kingdom, 2005.

Conferences and Courses Attended

AS & MAS-CDT Annual Conference (Flash Presentation) - July, 2020.

ASMS (Reboot) (68^th Conference) - June, 2020.

EU FT-ICR MS (4^th Short Course) - University of Warwick, August, 2019.

MAS-CDT Annual Conference (Flash and Poster Presentation) - Somerset, United Kingdom, July, 2019.

Academic Societies

Member of the British Mass Spectrometry Society (BMSS)

Member of the American Society for Mass Spectrometry (ASMS)

Member of the Royal Society of Chemistry (RSC)

Awards

Engineering and Physical Sciences Research Council (EPSRC) Scholarship for Integrated MSc and PhD in Molecular Analytical Science, University of Warwick - September, 2018.

Extracurricular Interests

Photography- Primarily scientific, fine art and architectural photography.

Reading- Material relating to science fiction, cultural and comparative history, geopolitics and south-east Asian philosophy.

Publications

Basim R. Hussain
PhD Student

MAS-CDT and FT-ICR MS Group

Ion Cyclotron Resonance Laboratory
Department of Chemistry

Contact

Email

Basim.Hussain@warwick.ac.uk

ResearchGate/BasimHussain

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Address

MOAC DTC, Senate House
University of Warwick,
Coventry, United Kingdom
CV4 7AL