Day 1 :
- Track 1: Novel Approaches to Analytical and Bioanalytical Methods
Track:2 Analytical Methodology
Session Introduction
Seda Nur Topkaya
Ege University School of Pharmacy, Turkey
Title: Electrochemical DNA biosensors and their potential applications to nanobiotechnology
Biography:
Seda Nur Topkaya has completed his PhD in 2013 at Analytical Chemistry from Faculty of Pharmacy, Ege University, Turkey. She also conducted her PhD researches at Harvard and MIT for 1 year about tissue engineering. Her main research interests are electrochemistry, electrochemical based DNA biosensors, detection of drug-DNA applications and also 2D-3D tissue engineering. She has published more than 10 papers in reputed journals and serving as a reviewer of many international journals.
Abstract:
Electrochemical based biosensors have been recently recognized as potential candidates for the requirements of nanotechnology applications. Sensitive and rapid detection of very few amounts of target nucleic acids (DNA or RNA) in biological matrices has attracted considerable attention from many fields, such as clinical diagnosis, drug researches and environmental analysis. Electrochemical DNA biosensors offer a highly sensitive and promising method for the detection of hybridization, genetic polymorphisms and mutations, alterations of genes and potential drug-DNA interactions because of their short assay time, miniaturization, portability, and low-cost. The main principle of electrochemical DNA biosensors is based on the conversion of hybridization events into the analytical signals via a transducer. The most common way is the direct detection of DNA oxidation signals of guanine bases through voltammetric techniques by evaluating the intrinsic signal changes of bases. Specific DNA/RNA hybridization can also be monitored using selective redox indicators, amperometric techniques, nanomaterials or electrochemical impedance measurements indirectly. Electrochemical based detection methods meet the sensitivity requirements with its picomolar detection limit in real samples and selective for the target DNA/RNA.
Istvan Halasz
PQ Corporation, USA
Title: Precise analysis of elements in silica powders by LA-ICP-MS
Biography:
Istvan Halasz obtained his PhD in Hungary from the Hungarian Hydrocarbon Institute, where he developed and scaled-up efficient processes for pharmaceutical, fine chemical and petrochemical industries. Later, at the Hungarian Academy of Sciences and at USA Universities, he studied zeolite catalysis, oxide superconductor synthesis, and catalytic fume abatement for automobile exhausts. In the past 16 years, he has investigated the properties of silicates at PQ R&D. He chaired the Philadelphia Catalysis Club; is current President of North-East Corridor Zeolite Association (NECZA); edited a book on catalysis, and authored 110+ book chapters and papers, 7 patents, and 80+ conference presentations.
Abstract:
Silica is important component of many heterogeneous catalysts. Catalysis affects ~90% of all chemical products. For elemental analysis by AA or ICP these silica-based catalysts are dissolved by HF and other acids. HF is exceptionally dangerous because of its ability to diffuse through the skin where the fluoride ion binds calcium with subsequent disruption of electrical activity. Therefore, it is desirable to minimize its use to reduce risk and eliminate a lengthy and tedious dissolution process. We speculated that coupling laser ablation (LA) to an ICP-MS could fulfill this desire. However, LA cannot be used for powder samples and LA-ICP-MS is known to be much less accurate than liquid phase measurements, owing to inhomogeneous ablated particle size and inadequate analysis parameters. Here, we report the development of a LA-ICP-MS method for accurately analyzing powdered silica supported catalysts. We melt the powders with a mixture of Li2B4O7 - LiBO2 into a homogeneous solid bead, vaporize the surface with a laser, and then apply a small cyclone before the ICP. Moreover, we optimized the analysis conditions by using statistical experimental design of 11 parameters. Using three commercial zeolite catalysts having Si/Al ratios 2.6, 40, and 140, we show that different parameters significantly affect the accuracy of measuring their Al contents. The relative standard deviation, RSD, remains <5% over the entire concentration range tested, sometimes even <0.5%, which is better than that obtained by the HF dissolution technique.
Radim Vespalec
Academy of Sciences of the Czech Republic, Czech Republic
Title: Analytical tasks stemming from therapeutical prospects of electron deficient boron cluster compounds
Biography:
Radim Vespalec has received equivalent to PhD from the Institute of Physical Chemistry, Academy of Sciences of the Czechoslovak Republic, Praha, in 27. He received the scientific degree from Technical University of Pardubice, and the pedagogical Assoc. Prof. degree from Masaryk University Brno. He is Senior Scientist in the Institute of Biophysics. Web of Science reports his 80 scientific articles and also he has contributed to 3 monographs
Abstract:
The existence, reactions, structures and properties of compounds occurring in nature, and their synthetic analogues are explainable by the idea of two-center two-electron bond. These families contain either electron exact or electron rich building blocks from the viewpoint of electron structure. Electron deficient building blocks have never been found in nature, and exist only in synthetic species. Boron cluster compounds (BCCs) create the most intensely investigated family of species with electron deficient cluster. Their existence has been explained by the accumulation of unique electron deficient bonds, which bind together three boron atoms or, sometimes, their substitutes, in clusters. Pronouncedly electron deficient clusters either determine or substantially affect properties of BCCs, and their prospects. Therapeutical prospects attract the highest attention now, and many compounds with boron clusters are synthesized as candidates for therapeutical uses. These compounds must pass through mandatory studies and checks, which require variety of chemical analyses, identically with other compounds. However, analytical methods do not exist for analyses of compounds with boron clusters. The pieces of knowledge from chiral separation of BCCs prove the dissimilarity of some analytical properties of species with and without boron clusters, and indicate the absence of criteria for the a priori estimation of different analytical properties for compounds with and without clusters. Thus, missing analytical methods cannot be derived from existing knowledge. Analytical research of BCCs motivated by their medical prospects is the best way to preventive elimination some obstacles, which may hamper medical uses of compounds with boron clusters.
Tudor Arvinte
University of Geneva, Switzerland
Title: New analytical methods to measure protein aggregates in biopharmaceuticals
Biography:
Tudor Arvinte, PhD received his academic training in physics at the University of Jassy, Romania, and his PhD in biophysics from the University of Düsseldorf, Germany. He performed his Doctoral work and Postdoctoral stage at the Max-Planck-Institute West Germany and held numerous research positions in Europe and the USA: at C.N.R.S., Orléans, France, at Cornell University, New York, at Texas A&M University, and at the Biophor Corporation, College Station, Texas, USA. In 1989 he joined Ciba-Geigy Pharmaceuticals in Horsham, England, and in 1994 he moved to Ciba- Geigy in Basel, Switzerland. Until 2002 he worked as Head of Exploratory Formulation, Novartis Biotechnology Development & Production, Basel. He worked on the characterization and formulation of more than 130 protein and peptide drugs. He has over 80 publications and holds 13 patents on formulations of proteins: one patented formulation for hirudin is used in the marketed product. Since 2001 he is invited Professor at the School of Pharmacy, University of Geneva, Switzerland where he is teaching a post-graduate course on “Formulation and delivery of protein biopharmaceuticals”. He is also Visiting Professor at the Department of Pharmacy, School of Health and Life Sciences King’s College London, UK. In 2003 he co-founded Therapeomic, Inc., a biotech company focused on developing formulations for biopharmaceuticals in collaborations with pharmaceutical companies.
Abstract:
A good characterisation of the protein aggregation states and of the presence of particulate matter in biopharmaceuticals can only be achieved through a convergence of evidence from numerous classical and orthogonal analytical methods. Based on case studies, different new orthogonal methods will be presented. No single method can be used as an absolute characterisation of the aggregation states. Only by using together many different, complementary methods we can obtain reliable conclusions and reveal an abroad picture on the protein aggregation states and the presence of particulate matter in biopharmaceuticals.
Syed N Alvi
King Faisal Specialist Hospital & Research Center, Saudi Arabia
Title: Determination of amlodipine in human plasma by liquid chromatography–tandem mass spectrometry and its application to pharmacokinetic & bioequivalence studies
Biography:
Syed N Alvi obtained his PhD in Chemistry from Osmania University, Hyderabad, India in 2001. He is currently Scientist at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia. He his research interest includes method development and validation and application for pharmacokinetic and bioequivalence studies.
Abstract:
A rapid Liquid Chromatographic-Tandem Mass Spectrometric (LC-MS/MS) assay for the measurement of amlodipine level in human plasma was developed and validated. Amlodipine and tizanidine (IS) were extracted from plasma using mixture of dichloromethane and tertiary butyl methyl ether (1:3, v:v) and reconstituted with 100 µl mixture of methanol and water (1:1, v:v). The mobile phase consisted of acetonitrile and 0.1% formic acid (80:20, v:v). Analysis was performed at room temperature using a reversed phase Atlantis dC18 (2.1x100 mm, 3 µm) column. The components of interest were detected in the positive ion mode of electrospray ionization using transition 409.8 → 238.4 and 254.3 → 43.9 for amlodipine and the IS, respectively. The relationship between amlodipine concentration in plasma and peak height ratio of amlodipine to IS was linear 0.9868 in the range of 0.2–20 ng/ml; intra and inter-day accuracy between 101-114%, and coefficient of variations were ≤14.4%. The quantification limit of amlodipine in 0.5 ml plasma was 0.2 ng/ml and the detection limit was 0.1 ng/ml. The method was successfully validated and applied in a bioequivalence study of four tablet formulations of amlodipine.
Florence Geneste
University of Rennes ,France
Title: Flow electrochemical sensor for trace analysis of heavy metals
Biography:
Florence Geneste was graduated from the Ecole Supérieure de Chimie Physique Electronique de Lyon. She completed her PhD in Chemistry in 1996 at the University of Paris-Sud. She worked as a Postdoctoral researcher in Thomson-CSF (Orsay) and then at the University of Cambridge, with Prof. A.B. Holmes from 1997 to 1999. She joined the University of Rennes as Associate Director of Research CNRS in 1999. Her research interest is focused on the modification of porous electrodes for application in flow electrochemistry. She is involved in the development of novel analytical methods for sensors and biosensors applications and in supported catalysis.
Abstract:
Flow electrochemical sensors are highly effective to enhance mass transport when a pre-concentration step of the analyte is required to achieve trace analysis. They are advantageous because they are easily automatable and allow approaching the ideal real-time analysis. Porous electrodes are relevant to flow electrochemical systems due to their good hydrodynamic properties and their high specific surface area. In this work, we will present the use of graphite felt as electrode material for trace analysis of heavy metals in flow systems. Its properties combined to a well-suited flow electrochemical cell give rise to efficient accumulation step in anodic stripping voltammetry. Since this material is easy to modify by electro grafting methods, selective analyses can be performed thanks to convenient receptors covalently attached on the surface of the fibers. Electro grafting methods involving reduction of diazonium salts and oxidation of amines in organic and aqueous media were used to prepare methoxy, carboxylate and cyclam-modified electrodes. The efficiency of the immobilization methods was checked by cyclic voltammetry using redox probes and by XPS analyses. The performances of the modified electrodes for trace analysis of copper were then evaluated in terms of sensitivity and selectivity. The influence of the electro grafting method and the nature of the linker on the electrochemical signal obtained by linear sweep stripping voltammetry analysis after a preconcentration step performed at open circuit was highlighted.
Li Niu
Chinese Academy of Sciences, China
Title: R&D of electrochemical sensors & instruments in ELMAT & SKLEAC
Biography:
Li Niu has completed his PhD at the age of 30 years from Changchun Institute of Applied Chemistry and postdoctoral studies from the Åbo Akademi Unversity. He is the Director of Engineering Laboratory for Modern Analytical Techniques, CIAC and CAS. He has published more than 170 papers in reputed journals and has been serving as Editorial Board Members in several journals.
Abstract:
Fundamental electrochemical investigations in combination whatever with materials, environment, life science, and other disciplines, only those 3 possible & practical applications for the human being are available at the moment, such as new methods, devices and instruments. As known, electrochemistry technique is an important member in the whole family of the instrumental analysis. Especially, in coupling with other techniques, we can know much information about the interfacial interaction, structural features, reaction process, mass transfer, etc. during electrochemical running. Unfortunately, imported instruments & equipment occupies the leading position in China within the past decades, electrochemistry system is also still the world of imported products in China, such as Princeton, CHI, BAS, Gamry, Biologic, etc. Besides those electrochemical instruments, some typical and daily-used electrochemical sensors, such as blood glucose analysis, industrial control gas sensors, heavy metal ion monitoring, blood gas analysis, met the same problem in China. With the great increase of human industrial production, water quality analysis is becoming more and more necessary. A few typical electrochemical devices and methods for water monitoring, such as DO, COD, heavy metals, etc. have been developed successfully. In addition, various methods and sensors for bioanalysis & food analysis have been explored too. Furthermore, a series of electrochemical instruments has been completed, which ranged from basic models to advanced, from potentiostat to bipotentiostat, even to multichannel, from integrated spectrometers to electrochemical imaging & etching, etc. Those developed instruments have been widely used in many institutes & universities in China.
Pawanpreet Singh
University Institute of Pharmaceutical Sciences, India
Title: Solid state analytical techniques to characterize cocrystals: Ciprofloxacin–hippuric acid co-crystal
Biography:
Pawanpreet Singh has completed his Masters in Pharmacy from Punjab Technical University at the age of 23 and is presently doing PhD from University Institute of Pharmaceutical Sciences, Punjab University, India. He is doing his research work on the topics like crystal engineering, polymorphism and crystal structure prediction.
Abstract:
Co-crystals are crystalline single phase materials composed of two or more different molecular and/or ionic compounds generally in a stoichiometric ratio which are neither solvates nor simple salts. They are of interest to both academic research as well as industry as they represent the opportunity to access new solid forms with modified physical properties including dissolution rate, physical stability and altered pharmacokinetic profile of the API subjected for co-crystallization. The present work represents Ciprofloxacin-Hippuric acid cocrystal which was prepared by solvent assisted grinding method. It was primarily characterized by FTIR showing shift in –COOH stretch at 3264.1 cm-1 in cocrystal as compared to 3405.2 and 3343.9 cm-1 in drug and coformer respectively. The C-N stretch also shifted from 1380 cm-1 to 1385.2 cm-1. The cocrystal was then confirmed by Differential scanning calorimetry showing single melting endothermic transition at 218.9oC irrespective of both components showing formation of new stable phase. XRPD pattern of cocrystal shows disappearance of two major peaks at 14.7 and 24.9o 2θ while another major peak shows drastic shift from 25.5 to 19.5o 2θ. Fortunately, the development of XRPD equipment and structure solving algorithms makes it possible to extract the crystal structure from the XRPD pattern. Recently, peers introduced a protocol to confirm the refined result using combination of XRPD and solid state NMR data. The NMR chemical shift values (1H, 13C, 15N) were also computed to validate the refined cocrystal structure.
Tan Guan Huat
University of Malaya, Malaysia
Title: Electrochemical preparation and characterization of gold nanoparticles graphite electrode: Application to myricetin antioxidant analysis
Biography:
Guan Huat Tan is Professor in Analytical Chemistry at the Department of Chemistry, University of Malaya. He started his teaching career at the University of Malaya in 1978 after completing his PhD in Analytical Chemistry from Duke University. He has supervised eight PhD and six MSc students and many thesis projects on environmental analysis of organic chemical pollutants in Malaysian waterways and pesticides in fruits and vegetables by using techniques such as GC, GC-MS, HPLC and LC-MS. He is currently supervising five PhD and one MSc student for their theses. He is also currently doing studies on developing microextraction techniques coupled to GCMS and LCMS for analysis of pesticide residues in food matrices such fruits and vegetables. He has presented and published many papers on the monitoring of priority environmental organic pollutants at various international and local symposiums and conferences as a result of his research findings.
Abstract:
Graphite has been an attractive material for electrochemical analysis due to it attributes in terms of its physical, chemical inertness and also because of its low cost, abundantly available, reusable and can be obtained in various forms such as rod, sheet, and flexible sheets. However its electrochemical properties are often a drawback when compared to other solid metal electrode, but this can be improved by surface modification of the graphite with noble metal nanoparticles. In recent years, antioxidant analysis by electrochemical techniques has been the focus of many studies; this is because the technique is sensitive, rapid and possible for field analysis. These advantages had overcome the problem of anti-oxidant analysis, which are sensitive to environment oxidation and therefore a fast analysis procedure is always preferable. In this present paper, we have carried out the electrochemical improvement of a recycled graphite electrode through an optimized procedure by electro-deposition of the gold nanoparticles on the graphite surface. An improvement on the electrochemical properties of the graphite by enhancement of its effective surface area, heterogeneous electron transfer rate, over potential and also the sensitivity has been observed. Application of the fabricated gold nanoparticles graphite electrode was also successfully optimized for the qualitative and quantitative analysis of myricetin.
- Track:3 Bio analytical Methodology
Track 4: Analytical Techniques in Pharmacogenomics
Track 5: NMR and Analysis of Small Organic Molecules
Session Introduction
Khondaker Miraz Rahman
Transcriptogen Limited, UK
Title: Targeting transcription factors with DNA interactive small molecules
Biography:
Khondaker Miraz Rahman graduated as a pharmacist from the Faculty of Pharmacy of University of Dhaka, Bangladesh in 1996. He worked for 3 years as a research and development pharmacist at SK&F Pharmaceutical before moving to academia in April 2001 and joined the Pharmacy department of University of Asia Pacific as a Lecturer. In October 2003, he was appointed as a Lecturer in pharmaceutical chemistry at Dhaka University and was promoted to Assistant Professor in June 2005. He completed his PhD research at the London School of Pharmacy (now UCL School of Pharmacy) under the supervision of Professor David Thurston. He joined the CRUK Protein-Protein Interaction Research Group as a CRUK Research Fellow in July 2009. He was appointed as a Lecturer in Medicinal Chemistry at King’s College in May 2012.
Abstract:
Transcription factors are regulatory macromolecules that induce profound and sustained effects in cells by interacting with, and modulating the expression of genes responsible for critical cellular processes. Interaction of a small molecule with the consensus DNA sequence can prevent a transcription factor from recognizing its cognate sequence, thereby preventing expression of genes associated with the transcription factor. Transcription factor inhibition is an exciting new area of drug discovery, and is considered by some experts to represent the “next wave” of cancer therapeutics following the kinase inhibitors (which have now reached maturity) and the antibody-based approaches which are now in the ascendancy. There are few approved drugs at present that work by selectively inhibiting transcription factors, and so there is significant clinical and commercial potential. From a scientific/clinical perspective, this approach has the advantage that a selective and potent inhibitor would act at the ultimate signalling point of gene expression (i.e., the promoter region of a gene) thus directly modulating the expression of genes carrying the cognate DNA recognition site of the targeted transcription factor. Furthermore, there are sub-families of transcription factors (e.g., STAT1 and STAT3), and it may prove possible to target these independently, thus achieving fine-control over transcription. This is an important distinction from the kinase inhibitors that also modulate gene expression, but have multi-pathway downstream targets and are rarely highly selective, as their kinase target will usually control a range of transcription factors. The talk will explore innovative DNA targeting therapeutic approaches to develop low molecular weight “druggable” molecules that can be targeted to unique transcription factor recognition sites in the human genome. Various mechanisms can be used including the inhibition of protein-protein interactions (PPIs) and protein-DNA interaction (PDIs). A number of duplex-DNA and promoter G- Quadruplex-binding agents are being developed to target the PDI interaction, and some examples will be presented
Aly Moussa
Anses Lyon Laboratory, France
Title: The biological activity of streptomycin and related molecules are associated with the presence of 2 functional guanidine groups
Biography:
Aly Moussa obtained his BVSc from Cairo University, Egypt; Dr. Vet. Med. From Justus Liebig university, Germany and PhD from Claude Bernard University, France. He worked 4 years at IFFA-Mérieux Laboratory; Lyon- France, for 20 years was the chief of virology service at the French Bovine Pathology laboratory. Then for 8 years he was concerned at the national agency for sanitary security of aliments with research on the pathogenic prion proteins. He has published many papers in the fields of Virology and Transmissible Spongiform Encephalopathy’s.
Abstract:
The presence of at least 2 functional guanidine groups within a non-polymeric hydrophilic molecular system was suspected to be the chemical structure of streptomycin implicated in the interaction with proteins. To prove this hypothesis, several chemicals possessing two guanidine groups as streptomycin (dihydrostreptomycin, bis-3-aminoproylamine, guanidine hydrochloride, triethylene tetra mine and spermine tetra-hydrochloride) were tested for evaluating their interaction with the pathogenic prion protein (PrPsc). All molecules sharing common chemical function with streptomycin reproduced aggregation and precipitation of the prion protein. The interaction of streptomycin with proteins is optimum at alkaline PH and takes place through hydrogen bond transfer between the 2 guanidine groups on streptomycin and the amino-acids of one or several prion peptides ruling the possibility of a Schiff-base reaction. Streptomycin had proved valuable for earlier and higher immunological detection of prions in clinical samples due to protein aggregation as well as to a better attachment of antibodies to their epitopes through electric charge transfer on the protein surface. These changes of the surface electrostatic charges induced by streptomycin affect also the prion stability leading to a reduced infectivity.
Joshua M Hicks
Catalent Pharma Solutions, USA
Title: NMR quantification in the verification of compounds: Simple to complex mixtures
Biography:
Joshua M Hicks has completed his PhD from Oregon State University in 2005 from the department of Biochemistry & Biophysics, and a Postdoctoral tenure at Stockholm University. He is a Lead Scientist in the Structural group at Catalent, a premier drug development, delivery and supply partner organization for drugs, biologics, and consumer health products. He has been highly active in the design, development and implementation of NMR applications in pharmaceutical applications for over 9 years.
Abstract:
Quantification is one of the most important pieces of information when using compounds in testing. It is important that the correct concentration is used when measuring within applications such as monitoring of reactions, proteinligand binding for the measurement of binding constants, dosage, fragment based screening, and monitoring of branching rates of polymers, among others. Such rate limiting steps are self evident in compound library screening where one must verify concentration in a high throughput means. With the improvements in software and NMR instrumentation, it is possible to have on the fly verification where concentration can be a key part of the verification process. Since the submitter has knowledge of the (suggested) structure, a known submission mass and a volume, the calculations for integral accounting and assignment can be output. Concentration is a key aspect because deviations are indicative of compounds purity from other compounds as well as impurities not directly observable by NMR such as salts. Additionally the solubility of the compound and stability are observed due to large changes in calculated versus measured concentration. All important aspects when validating a regular method for development/validation of definitive verification of a compound or mixture of compounds.
Mei-Hwei Tseng
University of Taipei, Taiwan
Title: Determination of activated methyl cycle metabolites and glutathione in cabbage upon sulfate deprivation and copper toxicity
Biography:
Mei-Hwei Tseng had completed her PhD from National Taiwan University and Postdoctoral studies at the Laboratory of Plant Physiology, University of Groningen, The Netherlands.
Abstract:
The activated methyl cycle is a central metabolic pathway used to generate (and recycle) several important sulfur-containing metabolites including methionine, S-adenosylmethionine, S-adenosylhomocysteine and homocysteine and enable methylation. Glutathione is a ubiquitous intracellular peptide with diverse functions that include antioxidant defence and detoxification of toxic metals and xenobiotics. Glutathione is present in plant tissue in the thiol-reduced (GSH) and disulfide-oxidized (GSSG) form. We had developed a precise and sensitive method for the simultaneous measurement of several sulfur metabolites based on liquid chromatography coupled with tandem mass spectrometry and 34S-metabolic labelling of sulfur-containing metabolites in Arabidopsis thaliana seedlings. Sulfur metabolites were extracted from freeze-dried roots and shoots of cabbage (Brassica pekinensis) after 14 and 21 days of plant cultivation with an aerated 25% Hoagland nutrient solution. The impact of sulfate deficiency and copper toxicity (10 µM) on the levels of activated methyl cycle metabolites and glutathione in cabbage were determined by our method, which is based on stable dilution-based liquid chromatography-electrospray ionization-tandem mass spectrometry. The levels of these metabolites only declined during the initial period of copper toxicity and most of them were further restored, while all the levels of these metabolites except that of S-adenosylmethionine in the shoot declined during sulfate deficiency, resulting in significantly higher ratios of S-adenosylmethionine/S-adenosylhomocysteine and GSH/GSSG in the shoot.
Vitor H Pomin
Federal University of Rio de Janeiro, Brazil
Title: Advances in structural biology of glycosaminoglycans by 15N-NMR spectroscopy
Biography:
Vitor H Pomin (MS, PhD) is an Assistant Professor of Biological Chemistry, Biochemistry, Glycobiology, and NMR Spectroscopy at Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Brazil, since May 2011. He pursued his undergraduate studies in Biological Sciences and graduate studies in Biological Chemistry at the same university. He received his Diplomas of Licentiate, MS, and PhD in 2003, 2005 and 2008, respectively. His MS and PhD were supervised by Prof. Paulo A S Mourão. After this period, he pursued a Post-doctorate experience at the Complex Carbohydrate Research Center, University of Georgia, United States, until April 2011, under the supervision of the Eminent Scholar of NMR spectroscopy Prof. James H. Prestegard. He has over 40 published articles in high-impact peer-reviewed journals, 11 book chapters, besides being editor of 6 academic/scientific books. He serves as an Editorial Member and frequent reviewer of many internationally recognized journals like Biopolymers, Carbohydrate Polymers, Biochimica et Biophysica Acta-General Subjects, Marine Drugs, Phytochemistry, the Journal of Biological Chemistry, Glycoconjugate Journals, ACS Biochemistry, Current Protein & Peptide Science, and others. He conducts research on glycobiology (especially sulfated polysaccharides), structural (glyco) biology and NMR spectroscopy.
Abstract:
With the recent developments to enhance sensitivity in solution NMR spectroscopy, such as the advent and spread of high-magnet fields worldwide, cryoprobe technology, isotopic labeling techniques, and new combinations of 2D pulse sequences, a new direction in structural analysis of glycosaminoglycans (GAGs) by NMR spectroscopy has emerged. The current scope is the one more dedicated to the less sensitive amide 15N isotope of hexosamines rather than the commonly used anomeric and ring 1H- or 13C-resonances of uronic acids and hexosamines. Given that GAG types are basically classified upon their composing hexosamine types together with the variations of their sulfation patterns, 15N-related NMR studies on native GAGs, oligosaccharides or the different composing amino sugars have proved to be quite informative in both structural or dynamic point-of views, despite the low number of the resultant NMR signals. This in turn reduces significantly chemical shift degeneracy as at the same time facilitates spin/structural assignments. This section is dedicated to cover the principal contributions made so far by solution 15N-NMR spectroscopy toward the progress of the structural biology of GAGs in the current glycomic age.
MarÃa José Ruiz-Ãngel
University of Valencia, Spain
Title: Comparison of the performance of amines and ionic liquids as additives in RPLC for the analysis of basic compounds
Biography:
María José Ruiz-Ángel obtained her PhD from the University of Valencia (Spain) in 2003. In 2004‒2006, she was granted with a Post-doctorate fellowship in the Laboratoire des Sciences Analytiques at the University Claude Bernard in Lyon (France). In 2007, she was awarded with a Ramón y Cajal research position in the Department of Analytical Chemistry at the University of Valencia, where she is Professor since March 2012. She has written over 50 research articles, most focusing on secondary equilibria using surfactants and ionic liquids, fundamental studies in HPLC and development of analytical methods for pharmaceutical and clinical samples.
Abstract:
The residual silanols, present in silica-based stationary phases used in reversed-phase liquid chromatography, are responsible for additional ion-exchange interactions with positively charged solutes that result in undesirable broad and tailed peaks. In order to enhance the chromatographic performance of these compounds, amines of different nature have been traditionally added to the mobile phase. These cationic reagents decrease the silanol activity by covering or blocking the silanol sites, which yields symmetrical peaks. The number of available amines as potential additives is high, but recently, the possibilities have even expanded with the introduction of ionic liquids (ILs) as a powerful alternative. In consequence, the offer is now so wide that the selection of the most suitable blocking silanol agent is not easy, being possible that among different solutions the best is not always chosen. ILs seems to be the fashionable option, which has somehow relegated the use of classical amines, or extended wrong ideas about the supposed ineffective results of amines as silanol suppressors. Several reasons for these assumptions can be addressed: The reduced number of amines that are compared with ILs, insufficient understanding of the mechanisms of retention, and an incorrect interpretation of the silanol suppressing potency, which is exclusively evaluated based on the retention behavior. In this work, a comprehensive study of the silanol suppression effect given by two amines and a group of ILs for the analysis of a set of basic β-blockers is carried out. The results are analyzed considering retention and peak shape, which allows elucidating the protection mechanism of both types of additives.