Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 7th World Congress on Mass Spectrometry Rome, Italy.

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Scientific Program Day 1
Scientific Program Day 2

Day 1 :

Keynote Forum

R V Krishnamurthy

Western Michigan University, USA

Keynote: Application of stable nitrogen isotopes in human colorectal cancer research

Time : 10:05-10:35

Conference Series Euro Mass Spectrometry 2018 International Conference Keynote Speaker R V Krishnamurthy photo
Biography:

R V Krishnamurthy obtained his PhD from the Physical Research Laboratory, Ahmedabad, India and worked as a Fellow of Geochemistry at the California Institute of Technology for seven years. In 1991, he moved to the Western Michigan University to set up a program in Stable Isotope Geochemistry. He is currently a Professor in the College of Arts and Sciences. He has published more than 60 papers in high impact journals such as Science, Nature, Geochimica et Cosmochemica Acta, Geophysical Research Letters, Applied Geochemistry, Geobiology and Scientific Reports. His research spans Biochemistry, Geochemistry, Hydrology, Atmospheric Sciences and Cosmochemistry. He is featured in Who’s Who in North American science.

Abstract:

Application of stable isotopes, especially carbon and nitrogen, are becoming a powerful tool in medical science. A novelapplication of the natural abundances of nitrogen isotopes, 14N and 15N in the understanding of amino acid metabolism inhuman colorectal cancer cells was carried out. Nitrogen isotope ratios are of particular advantage to understand the metabolic stateof cancer cells, since most biochemical reactions involve transfer of nitrogen. In this study nitrogen isotopes of individual amino acids from human colorectal cancer cell lines were analyzed. Significant effects were noticed in the case of glutamic acid, alanine,aspartic acid and proline between cancer and healthy cells. The data suggest that glutamic acid is a nitrogen acceptor while alanine,aspartic acid and proline are nitrogen donors in cancerous cells. One plausible explanation is the xtransamination of the three acids toproduce glutamic acid in cancerous cells. The findings are significant since glutamic acid and alanine make up more than 60 per centof the total amino acids in the human body. Glutamine is a significant source of energy for cells and also a prime donor of nitrogenin the biosynthesis of  amino acids. Several studies have advocated the role of glutamic acid incancer therapy. Identification ofmetabolic signatures in cancer cells will be crucial for advancement of cancer therapies based on the cell’s metabolic state.

Keynote Forum

Purushottam Chakraborty

Saha Institute of Nuclear Physics, India

Keynote: Alkali containing molecular-ion based SIMS: Fundamentals and potential applications in the chemical analysis of low-dimensional materials

Time : 10:05-10:35

Conference Series Euro Mass Spectrometry 2018 International Conference Keynote Speaker Purushottam Chakraborty photo
Biography:

Purushottam Chakraborty is a senior professor at Saha Institute of Nuclear Physics, Kolkata, India and an honorary professor at the University Of Pretoria, South Africa.His research interests range from ‘ion beam analysis of materials’ to ‘x-uv optics and photonics’. He worked at many renowned centres like FOM – Institute for Atomic andMolecular Physics, Padova University, ICTP, Laval University, Osaka Electro-communication University, etc. He has published more than 125 papers including reviews and book-chapters. He has been awarded the ‘most eminent mass spectrometrist of India’ and is one of the world leaders in Secondary Ion Mass Spectrometry (SIMS).

Abstract:

If alkali metals such as Cs, Li, Rb, K, Na, etc. (referred as A in general) are present in the neighborhood of the probing element(M) on a sample surface, quasi-molecular ions can be formed by the attachment of these alkali ions [(MA)+ formation] in thesecondary ion mass spectrometry (SIMS) process. Formation of these MA+ molecular ions has astrong correlation to the atomicpolarizability of the element M. The emission process for the re-sputtered species M0 is decoupled from the MA+ ion formationprocess, in analogy with the ion formation in secondary neutral mass spectrometry (SNMS), resulting in a drastic decrease in the conventional ‘matrix effect’ in SIMS. Although the detection of MA+ molecular ions in SIMS has found its applicability in directmaterials quantification, it generally suffers from a low useful yield. In such cases, detection of (MA)n+ (n=2, 3,….) molecular ionsoffers a much better sensitivity (even by several orders of magnitude), as the yields of such molecular ion complexes have oftenbeen found to be higher than that of MA+ ions. The recombination coefficient of MA+ or MA2+ molecular species depends onthe electro-positivity or electro-negativity of the element M, respectively. Apart from the surfacebinding energy of the respectiveuppermost monolayer, the changes in local surface work-function have often been found to play a significant role in the emissionof these molecular ions. Although these MAn+ molecular-ion based SIMS has great relevance in the analysis of materials, acomplete understanding on the formation mechanisms of these ion-complexes is still lacking. A procedure, based on MAn+-SIMSapproach, has been proposed for the accurate germanium quantification in molecular beam epitaxy (MBE)-grown Si1−xGex alloys.The ‘matrix effect’ has been shown to be completely suppressed for all Ge concentrationsirrespective of impact Cs+ ion energies.Cesium, the fifth alkali element, is the most reactive of all the metals. The methodology hassuccessfully been applied for directquantitative composition analysis of various thin film and multilayer structures. Recent study on various ZnO-based nanostructures has successfully been correlated to their photo-catalysis and photoemission responses. The present talk will address the complex formation mechanisms of MAn+ molecular ions and potential applications of the MA+-SIMS approach in chemical analysis of low dimensionalmaterials and nanostructures.

Keynote Forum

Steven J Soldin

National Institutes of Health, USA

Keynote: The role of mass spectrometry in improving the diagnosis and management of thyroid disease

Time : 11:20-11:50

Conference Series Euro Mass Spectrometry 2018 International Conference Keynote Speaker Steven J Soldin photo
Biography:

Steven J Soldin has obtained his PhD in Biochemistry at the University of the Witwatersrand in Johannesburg, SA. After a Postdoctoral year at the University of Torontohe enrolled in a Clinical Biochemistry program at that University, obtained his Diploma in Clinical Biochemistry and was boarded in this discipline in both Canada and theUSA. He has been a tenured Professor at both the University of Toronto and the George Washington University School of Medicine. He is currently Senior Scientist in the Department of Laboratory Medicine at the National Institutes of Health, Bethesda, USA. He has published 275 papers in peer reviewed journals and has many patents.

Abstract:

This talk will focus on how mass spectrometry improves both diagnosis and treatment of patients with hypothyroidism (20million in the USA). We will discuss current problems with immunoassays for thyroid testing which frequently lead to thewrong diagnosis and poor patient management. In contrast the diagnosis of hypothyroidism is more reliable utilizing UF LCMS/MS (ultra-filtration tandem mass spectrometry) for the measurement of FT4, FT3, TT3 and TT4. The suboptimal current role ofthe FDA in licensing inaccurate and unreliable immunoassay methods and the approaches of the AACC and IFCC to harmonizeimmunoassay platforms with reference LCMS/MS methods will be critiqued. Finally evidence of poor performance of thyroidstimulating hormone (TSH) tests in predicting thyroid disease will be discussed.

  • Ionization Techniques| Applications of Mass Spectrometry | Analytical Science and Separation Techniques | New Approaches in Mass Spectrometry | Recent Advances and Development in Mass Spectrometry | Mass Spectrometry in Proteome Research | Proteomics and its Applications | Fundamentals of Mass Spectrometry
Location: Olimpica 1

Session Introduction

Eduard Rogatsky

Albert Einstein College of Medicine, USA

Title: 2-dimensional chromatography – mass spectrometry applications in clinical research
Speaker
Biography:

Eduard Rogatsky completed his M.Sc in physical chemistry from Belarus State University, PhD in bioanalytical chemistry from Bar-Ilan University (Israel) in 1999, andpostdoctoral studies at Albert Einstein College of Medicine, NY. He joined the faculty there in 2001, and is currently a Senior Associate Scientist and Director of Mass Spectrometry in the Biomarker Analytical Resource Core Laboratory, Einstein-Montefiore Institute for Clinical and Translational Research, Bronx, NY, USA.

Abstract:

2D chromatography – efficient way to increase peak capacity. It is important for HPLC-UV applications requiring baseline peaksseparation. In contrast, MS detection utilizes ions resolution by m/z and chromatographic (non-isobaric) peaks overlay is often in LC/MS/MS analysis. Typical benefits of 2D chromatography implementation in Applications of Mass Spectrometry are minimum of signalsuppression, low and stable background and excellent peak shape. Given presentation we will be focused on three case studies: 1.The robust and routine method of sorbitol analysis from human plasma by LC/MS/MS. 2. Non-digest liberation of biomarkers from plasma: a unique two-stage ultrafiltration approach combined with 2D chromatography and mass spectrometry analysis. 3. Human C-peptide analysis by 2D RP-RP LC/MS. These case studies demonstrate additional unique advantages of 2D/column switching applications in mass spectrometry beyond mentioned above signal suppression/matrix effects minimization, background and peak shape improvements. Addition of switching valve and extra HPLC pump may contribute drastic improvements in LC/MS analysis.

Damien Bazin

Chromatotec, France

Title: Development of on-line and field dual TD GC – MS for automatic VOC monitoring on petrochemical sites
Speaker
Biography:

Damien Bazin received his PhD in Physical Chemistry at the University of Bordeaux I. He worked at the CNRS under the supervision of Pr Chrystel Faure and published major publications on the preparation and characterization of structured surfaces. He is now a Product Manager at Chromatotec® and works on the development of GCMS/ FID instruments and applications.

Abstract:

Ambient air is polluted by many semi-volatile and volatile organic compounds (SVOCs and VOCs) coming fromanthropogenic and natural sources. VOCs from PAMS, TO14 and TO15 lists can be measured in many ranges of concentration, from pg/m3 up to mg/m3 depending on the location of the measurements. Due to the large number of molecules, the complete separation of all compounds is difficult to perform using chromatographic columns. Therefore, it is difficultto quantify precisely all compounds using a chromatography equipped with a nonspecific detector. The goal of this study is to perform automatic and continuous identification and quantification of SVOCs and VOCs using a dual thermal-desorber gas chromatograph equipped with two flame ionization detectors (FIDs) and one mass spectrometer (MS). The device is required to identify automatically co-eluted compounds by MS technology adapted to industrial context. The coupling of two different FID GCs to a single Quadrupole MS allowed by an elaborated multiplexing system is the originality of the project: one thermal desorption gas chromatography (TDGC) for light compounds (C2-C5) and one TDGC for heavy compounds (C6-C16) with specific analytical conditions for each system. A measurement campaign in petrochemical new site shows the concentration of about 100 compounds at different steps of the commissioning. Thanks to the continuous measurements every 30 minutes, variations of concentrations during specific hours can be monitored. Potentially co-eluted compounds like terpenes or organochlorinated are identified

Giovanni Meloni

University of San Francisco, USA

Title: Multiplexed synchrotron photoionization mass spectrometry: Characterization of combustion and atmospheric reactions
Speaker
Biography:

Giovanni Meloni is a Professor, Chemistry Department Chair and a Physical Chemist. Prior to joining the University of San Francisco, he carried out Post-doctoral research at the University of California, Berkeley and at Sandia National Laboratories. In this research, he used state-of-the-art techniques, both experimental and computational,
to study transition states, semiconductor clusters, and van der Waals species employing anion photoelectron spectroscopy, and hydrocarbon radicals using pulsedlaser photolytic initiation and continuous-laser absorption detection. His current research interests range from high-temperature physical chemistry to spectroscopiccharacterization of reaction intermediates important to atmospheric and combustion chemistry, especially focusing on biofuel molecules.

Abstract:

Synchrotron multiplexed photoionization mass spectrometry has proven to be a powerful and reliable experimentaltechnique to probe precise reactions relevant to both combustion and atmospheric chemistry by characterizing productsand intermediates, energetically via photoionization spectra and kinetically via time traces. The versatility of a side-sample flowtube reactor employing flash photolysis initiation of the reactions has been satisfactorily proven in recent years. The continuouslytunable synchrotron radiation is employed as the photoionization source. The synchrotron multiplexed photoionization massspectrometer at the advanced light source (ALS) of Lawrence Berkeley National Laboratory will be described and specificexamples will be presented. As a result of the multiplexing capabilities of this apparatus, each set of data comprises a threedimensionaldata block of time, mass-to-charge ratio, and photon energy as function of ion intensity. The reaction is initiatedwhen the photolysis laser is fired, i.e., this corresponds to the reaction starting time t0. The species generated in the reactionscan be followed in time and energy to provide kinetic traces and photoionization (PI) spectra, which is a plot of the ion signalof a chosen mass-to-charge ratio versus the photon energy. The PI plots are of great importance in product identificationbecause each species has specific Franck-Condon factors that translate into different shapes of the photoionization spectra. Inaddition, photoionization spectra not only assist in product identification, but also provide information relating to the relative concentrations of products of interest through the measurement of their photoionization cross-sections.

Yuliya E Silina

INM-Leibniz Institute for New Materials, German

Title: Organic and inorganic mass spectrometry as a helpful tool for bio-andenvironmental sensors design optimization
Speaker
Biography:

Yuliya E Silina has completed her PhD in Analytical Chemistry in Russia. Currently, she is a Principal Researcher of a team focusing on developments in the modern mass spectrometry, lab-on-a-chip devices, bio- and environmental sensing at Leibniz Institute for New Materials, Germany. She has published more than 30 papers in reputed journals and holds 11 patients for her inventions.

Abstract:

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been proven as a powerful tool for detailed informationon polymer composition due to its high sensitivity, high dynamic range, specificity and selectivity. TOF-SIMS can provide information about oligomer distributions, average molecular weights, fingerprint patterns for polymer identification,monomeric unit sequences, branching, cross-linking substitution, copolymer structures and additives or impurities. However,major challenges, viz. distinguish the surface from the rest of thematerial,unresolvable isobaric interferences regardless ofthe geometry of high-resolution instruments still remain unsolved. Herein, we will introduce an alternativestrategy utilizingliquid chromatography-electrospray ionization-tandem mass spectrometry (Q-TOF LC-MS), head space gas chromatography(HS-GC-MS) and high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) to study the polymer stability and degradation mechanisms. The examples discussed will provide an overview of using HR-ICP-MS and Q-TOF LC-MS to glucose biosensor design optimization, viz. multi-layer biosensor stability and to identify critical system parameters that affect the biosensor response. In addition, we will demonstrate how HS-GC-MS technique might be used to set an optimal bulk poly(dimethylsiloxane) (PDMS) sensor inluding thickness and cross-linking ratio as well as sampling/loading approaches aiming an application to fragrance controlled release maintained the constant ratio of volatile compounds. We believe, thereported strategy, will allow mapping the influence of the complete set of system input parameters on the sensor response, which subsequently opens up the possibilities for optimization of the design of sensors and their performance.

 

 

Nives Galić

University of Zagreb, Croatia

Title: Structural investigation of aromatic hydrazones and their complexes by ESI MS/MS
Speaker
Biography:

Nives Galić completed her BSc in Chemistry in 1992 at University of Zagreb; MSc in 1995 and; PhD in Analytical Chemistry in 1999. In 2011, she was elected for the position of Associate Professor and became Head of the Division of Analytical Chemistry. She has published over 30 papers which have been cited over 700 times. She was supervisor of 25 diploma thesis and two PhD theses (+ 6 in progress). She is a Leader of the project funded by Croatian Science Foundation.

Abstract:

Biological systems have difficulties to differentiate between Fe3+ and Ga3+ ions due to their nearly identical ionic radii, same charge, preferred coordination number and chemical behavior. However, Ga3+ lacks the redox activity of iron (3+/2+ redox chemistry) and is marked as “Trojan Horse” in biological systems. Aroylhydrazones can act as neutral, monoanionic or dianionic ONO tridentate ligands. In this lecture the coordination abilities of aromatic hydrazones derived from nicotinic acid hydrazide and differently substituted 2-hydroxybenzaldehydes towards Fe3+ and Ga3+ will be discussed. Stability constants and the stoichiometry of the corresponding M3+: hydrazone complexes in MeOH/H2O media were determined spectrophotometrically. Mass spectrometry was used for structural characterization of the complexes in solution. The MS/MS spectra and fragmentation pathways of ligands and the complexes will be presented.
 

Cilong Yu

Shenzhen Univeristy, China

Title: Microfluidic chip-based ionization coupling with mass spectrometry
Speaker
Biography:

Cilong Yu has completed his PhD from Tsinghua University, Department of Precision Instrument. He is working as Assistant Professor at Shenzhen University, College of Mechatronics and Control Engineering. He has published several papers in reputed journals about microfluidic chip ionization.

Abstract:

The coupling of microfluidic chip-based ionization to mass spectrometer (MS) has recently gained considerable attentionin the mass spectrometry community. In consideration of the miniaturization, integration, and universal disadvantages of microfluidic chip-based ionization coupled with MS, this study proposed three novel microfluidic ionization chips. All sources were fabricated by using the multi-layer soft lithography method. Three-dimensional (3D) flow focusing (FF)-based microfluidic ionizing source can realize two-phase FF with liquid in air regardless of the viscosity ratio of the continuous and dispersed phases. MS results indicated that the proposed FF microfluidic chip can work as a typical electrical ionizationsource when supplied with high voltage and can serve as a sonic ionization source without high voltage. To further improve the integration of ionization and simplified the operation of such device, the microfluidic self-aspiration sonic-spray ionization chip was fabricated. The experimental results demonstrated that the proposed microfluidic chip can implement the ionization of liquid samples depending simply on the gas applied on the sheath flow channel with much lower gas pressure. In addition, a microfluidic chip-based multi-channel ionization (MCMCI) was also developed to extend the application of microfluidic chip ionization to MS. This MCMCI implemented extraction of untreated compounds in complex matrices without sample pretreatments and dual sprays with high DC voltages simultaneously. All these microfluidic chip ionizations are expected to have various applications, particularly in the integrated and portable applications of ionization source coupling with portable MS in the future.

 

Xiao-qin Wei

Southwest Technology and Engineering Research Institute, China

Title: Failure analysis of nitrile rubber O-rings static sealing for packaging barrel
Speaker
Biography:

Xiao-qin Wei has completed his Master's degree at Southwestern University. She is mainly engaged in drug analysis and material failure analysis. She has published more than 10 papers in well-known journals.

Abstract:

Nitrile rubber O-rings seals for packaging barrel was stored in China tropical marine atmosphere environments for 10years, and then the sealing function of nitrile rubber O-ring was failed. By comparing the molecular structure, cross-link density, thermal decomposition, content of elements and chemical functional groups of the original nitrile rubber seals, the surface and interior of nitrile rubber seals storage for 10 years, a long-term natural failure mechanism was studied. The results showed that the surface content of dibutyl phthalate and dibutyl sebacate, the surface carbonyl peak height and the surface content of oxygen element were higher than that in internal; the surface cross-link density was lower than that in internal but still higher than in original sample; and surface carbon-to-oxygen ratio were lower than that in internal and original sample. After aging for 10 years, the weight loss of plasticizer decreased, and the main chain content increased. It can be inferred that nitrile rubber mainly undergoes oxygen-absorbing cross-linking reaction to form carboxylic acids and esters, which is accompanied by the migration and enrichment of two plasticizers to the surface, causing reductions in elasticity. The residual permanent compression set was lower than the design critical value, and the sealing function for the packaging barrel was lost, and a leak occurred.

Alveena Younas

Armed Forces Institute of Pathology (AFIP), Pakistan

Title: Diagnostic accuracy of cannabinoid testing by liquid chromatography-tandem mass spectrometry in human
Speaker
Biography:

Alveena Younas completed her MBBS in 2009 from Army Medical College Rawalpindi and got her degree from National University Of Science And Technology(NUST) with distinction. Presently she is in her second year of Post graduate training in Armed Forces Institute Of Pathology (AFIP), Pakistan in subject of Chemical Pathology. She has great interest in Proteomics and new analytical techniques being developed in field of Chemical Pathology

Abstract:

Objective: To determine the diagnostic accuracy of cannabinoids testing by liquid chromatography-tandem mass spectrometry (LC-MS) in human hair and to compare it with urine for detection of cannabis use in civil heavy vehicle drivers

Materials and Methods: This diagnostic accuracy(validation) study was carried out at Department of Forensic Medical Sciences Laboratory (FMSL), Forensic Toxicology Section, Armed Forces Institute of Pathology Rawalpindi, Pakistan. Hair and urine samples of about 151 civil heavy vehicle drivers were collected from various urban and rural areas of Punjab. Sampling technique was non-probability convenient. About 10 ml of urine volume was collected and stored at -20°C. Hair strands, about the thickness of a pencil shaft, were collected from the posterior vertex of scalp. It was cut as close to the root as possible, and kept at room temperature till further analysis. Separation of compounds was done on Agilent Poroshell 120 EC-C18 column (2.1 x 7.5 mm.7 micron) and analyzed on a 6460 Triple Quadrapole LC-MS along with MassHunter software.

Results: All the 151-male civil heavy vehicle drivers, who were included in the study, were categorized into three main groups. There were 69(71.5%) truck drivers, 43(28.5 %) were 20-wheeler drivers, whereas bus drivers were 39(25.8%). Mean age was 36±10.82 years. Subjects were stratified according to the age into four main groups: 20-25 years: 28(18.5%); 26-40 years: 73(48.3%), 41-60 years:47(31.1%) and >60 years:3(2%). Paired t test was applied to check significance of study at 95% confidence interval which was significant at p<0.05(p=0.00). Various parameters of diagnostic accuracy in hair and urine samples were: sensitivity (97% and 77%), specificity (92% and 93%), positive likelihood ratio(13% and 12%), negative likelihood ratio(0.04% and 0.24%), positive predictive value(89% and 83%), negative predictive value(98% and 91%) respectively. Overall diagnostic accuracy of cannabinoids in hair was 94.04% while in urine it was 88.67%. Receiving operating characteristics (ROC) curve was plotted which showed area under curve of 0.967 and 0.793 for hair and urine respectively, therefore signifying a better diagnostic accuracy of hair as compared to urine for cannabis detection.

Conclusion: This study highlights the importance of hair as an alternative biological matrix due to its good diagnostic yield, easy non-invasive specimen collection and distinctive potential of analyte stability, as well as wider period of detection as compared to urine.

 

Saranjam Khan

National Institute for Lasers and Optronics (NILOP), Pakistan

Title: Application and evaluation of Raman spectroscopy for dengue fever analysis and its comparisioin with the routine dengue diagnostic tests
Speaker
Biography:

Saranjam Khan did his PhD studies in 2011 from Division of Biomedical Physics, Innsbruck Medical University Austria. Currently he is working as Principal Scientist at National Institute for Lasers and Optronics (NILOP). His main reserach area includes spatial light modulator (SLM) based imaging, Raman and fluorescence spectroscopy. Recently he is working on the optical dignosis of different types of diseases. He is the author 27 peer reviewd papers in well reputed journals.

Abstract:

We are presenting the evaluation of Raman spectroscopy as rapid daignostics test for the detection of disease in thehuman blood serum. Blood samples of 84 clinically dengue suspected patients has been used in this study. Out of these 84 sample (95%) were positive based on nonstructural protein 1 (NS1), whereas(50%) and (52%) were positive based on Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies tests, respectively. Raman spectra from all these samples have been acquired in the spectral range from 600 cm-1 to 1700 cm-1 using 532 nm laser as an excitation source. The Raman spectra from normal healthy blood sera have also been obtained in the same spectral range under the same conditions. In the Raman spectra of normal samples three intense Raman-peaks have been observed at 1006, 1156 and 1516 cm-1. In the Raman spectra of dengue infected blood sera the intensity these three major peaks get suppressed whereas additional peak gets appearat 750, 855, 1032, 1306, 1333, 1355, 1580, 1603 and 1660 cm-1. The spectral differences between normal and abnormal (dengue infected) sera have been evaluated by using support vector machine (SVM) techniques. SVM models has been developed on the basis of three different kernel functions i.e. polynomial, linear, and Gaussian radial basis function (RBF). The model has been tested with the k-fold cross validation method. A diagnostic accuracy of about 85% with the precision of 90%, sensitivity of 73% and specificity of 93% has been achieved under these conditions.

Lingzhi Gong

Queen Mary University of London, UK

Title: Analysis of oligonucleotides by ion-pair hydrophilic interaction liquid chromatography/electrospray ionization mass spectrometry (IP-HILIC/ESIMS
Speaker
Biography:

Lingzhi Gong is research interests include mass spectrometry based analysis of small molecules and biomolecular molecules (nucleic acids, peptides, proteins) through hyphenated to a   chromatographic method (mainly liquid chromatography), and research into chromatographic retention mechanisms. His current work focuses on characterizing single- and double-stranded DNA/RNA, and protein/peptide - DNA crosslinking complex using hyphenated liquid chromatography and electrospray mass spectrometry (LC-ESIMS). Lingzhi currently runs Core Mass Spectrometry Research Facility at Queen Mary University of London.

Abstract:

Synthetic oligonucleotides are widely used in the polymerase chain reaction (PCR) as DNA primers or in molecular biologyas probes to screen for diseases, viral infections, and to identify genes. Sensitive and selective methods have always been demanded for the characterization of oligonucleotides, especially, when the oligonucleotides are applied as therapeutics. Ionpair reversed-phase (IP-RP) liquid chromatography has been commonly used for the analysis of oligonucleotides, but ion suppression is a major problem when coupling with electrospray mass spectrometry (ESI-MS). Although the introduction of hexafluoroisopropanol (HFIP) in the mobile phase has improved MS detection sensitivity of oligonucleotides, this mobile phase system results in a severe problem with adducts formation particularly if large oligonucleotides are analysed. An alternative chromatographic approach, hydrophilic interaction liquid chromatography (HILIC), was recently employed for the analysis

of oligonucleotides. It provided enhanced MS sensitivity with fewer adducts but lacked chromatographic resolution for some oligonucleotides. Here we improve chromatographic resolution whilst maintaining MS sensitivity by adding an ion-pairing reagent, triethylammonium acetate (TEAA), into the HILIC mobile phase. The IP-HILIC approach produces lower retention capacity and has the added benefit of providing simpler MS spectra, with fewer charge states, when comparing with HILIC.

 

 

Ali Mohammad-Djafari

CNRS, France

Title: Advanced Bayesian signal and image processing for mass spectrometry
Speaker
Biography:

There have been recent advances in different techniques of mass spectrometry. However, in many of these techniques there are common mathematical frameworks: inverse problems. In this work, a few of these inverse problems are presented and an overview of the methods to handle them is given. The Bayesian inference approach is a very useful approach to handle these problems as it give the possibility to account both for prior modeling of the signals and images and for the uncertainly associated to the measurement process. It also gives the necessary tools to estimate the hyper parameters and the remaining uncertainties in the proposed solution. To illustrate this, we take the deconvolution problem which is one of the main inverse problems in mass spectrometry and go through the different regularization and Bayesian inference methods and compare their relative performances.

 

Abstract:

Ali Mohammad-Djafari received the B.Sc. degree in electrical engineering from Polytechnic of Teheran, in 1975, the diploma degree (M.Sc.) from Ecole Supérieure d'Electricit(SUPELEC), Gif sur Yvette, France, in 1977, the "Docteur-Ingénieur" PhD degree and "Doctorat d'Etat" in Physics, from the University of Paris Sud 11 (UPS), Orsay, France, respectively in 1981 and 1987.He was Assistant Professor at UPS for two years (1981-1983). Since 1984, he has a permanent position at "Centre national de la recherche scientifique (CNRS)" and works at "Laboratoire des signaux et systèmes (L2S)" at Centrale-Supélec. He was a visiting Associate Professor at University of Notre Dame, Indiana, USA during 1997-1998. From 1998 to 2002, he has been at the head of Signal and Image Processing division at this laboratory.