Technological Platforms - Physical-Chemical Analysis - CRAPC

400-600 Hz NMR Spectroscopy

NMR spectroscopy is mainly known as an important analytical tool for a non-destructive structural elucidation of unknown synthetic and natural compounds (sugars, vitamins, steroids, polyphenols, fatty acids, enzymes, proteins…etc.).

Improvements in NMR instrumentation and technologies, have reoriented investigations to advantageously exploit NMR as a reliable quantitative analytical tool and opening horizon towards standardization of novel methodologies. Bi-dimensional 2D NMR have the inherent advantage to provide simultaneous information on both qualitative and quantitative aspects in food, pharmaceutical and polymer industries.

Scientific and Technical Research Center in Physico-Chemical Analysis (CRAPC-Algeria) have installed several 400-600 MHz NMR spectrometers within different technological platforms in Northern and Southern Algeria. NMR as a robust analytical equipment designed by BRUKER world‘s NMR leader, provides powerful performance at minimal cost.

Using standard operating software, TopSpinâ„¢ for exploring the structure of chemical compounds, NMR is the ideal solution for chemistry education and routine analysis.

CRAPC technological laboratories are now using Quantitative 1H-NMR, which provides an alternative rapid, selective, and accurate method for quantitative analysis of important polymers, plastics, resins, organic and bioorganic materials, pharmaceutical, cosmetic, essential oils, agro-alimental and food constituents.

The application of other NMR active nuclei, such as phosphor  or fluorine  is also considered as outstanding solutions to quantify metabolomics, biomarkers and physiological pathways. Simplicity, time gain and efficiency of QNMR attract many scientists and industrials to invest on this technique. The growing number of works involving QNMR methods has proved its potentialities. In this vein, CRAPC is actually developing and validating novel QNMR methods for food and agro-alimentary product quality control and authenticity, opening new issues towards digitalization, actualization/creation of databases, traceability and fraud detection.

Using NMR, we are strategically focusing on Traditional Food of high consumption rates (olive oil, honey, tea, coffee…). The collaborative national network will establish technical supports of standardized and validated QNMR methods for analyzing and controlling the quality of selected food products, such as vegetables (cereals and derivatives, crude and processed legumes and fruits), meat, eggs, honey, sugar, drinks (fruit jus, mineral water, wine and spiritual drinks), milk derivatives (cheese, butter), along with several sorts of vegetable oils.

QNMR aims covering all aspects of quality control, such as quantification of nutritional food components (vitamins, polysaccharides, sugars, proteins, fatty cores …etc.), control of food additive content (acid citric, aspartame …etc.), and the presence of harmful substances (toxins, pesticides, phtalates, higher rates of cholesterol, α-amylase …etc.). 

Our priorities is to create and digitalize novel NMR databases.

With NMR we can also act on food security and nutrition though providing novel norms to categorize the quality of food as: BIO, GMO, and ARTFICIAL, based on comparative studies of analytical QNMR, 1D and 2D data. 

Within the CRAPC-NMR network’s work plan, suitability/compatibility of food plastic packaging containing phtalates (and other hazardous materials) such as PET bottles (commonly used for vegetable oils, fruits juices and water conditioning) is an important issue for food security.

For this major concern, our recently developed QNMR method has been successfully applied to detect higher amounts of different phtalate compounds (directly extracted from PET-Bottles) comparing to the results issued form the chromatographic analysis.

Chromatographie phase gazeuse couplée à la Spectrométrie de masse- GC/MS

La chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC-MS) est une méthode séparative qui permet l’identification et le dosage des différents composés d’un mélange. Le principe est basé sur les différences d’affinité des composés du mélange avec la phase stationnaire et la phase mobile.

Le chromatogramme traduit la variation du soluté dans l’éluant en fonction du temps.

La spectrométrie de masse est une technique d’analyse structurale et de détection sensible. Elle permet de mesurer les rapports (m/z) de molécules individuelles et ionisées et de leurs produits de fragmentation, et permet ainsi de recueillir des informations sur sa nature, sa composition et même sur sa structure ou sa quantité sous certaines conditions Les différentes parties du spectromètre de masse sont maintenues sous vide par un système de pompage fonctionnant en permanence, la réalisation d’un vide suffisant, pour un bon fonctionnement d’un spectromètre de masse.

L’échantillon introduit dans la source sous forme gazeuse à partir d’un chromatographe CPG.
  • CARACTERISTIQUE EQUIPEMENT :

 Chromatographe : Hewlett Packard Agilent 6890 plus

 Spectromètre de masse : Hewlett Packard Agilent 5973

 

– SOURCE D’IONISATION IMPACT ELECTRONIQUE (EI-MS) :  consiste à obtenir sous vide l’interaction d’une molécule et d’un électron accéléré  à quelques dizaines de volts.

– ANALYSEUR QUADRIPOL :

– Gamme de masse : entre 15 and 700 amu avec 0.1 amu steps.

– Vitesse de scan : Max de 5200 amu/sec avec une résolution de  0.1 amu.

   – Sensibilité : Performance typique pour 1pg d’Octafluoro-naphthalène

– Signal to noise ratio meilleure que  20:1 sur la gamme de masse 50-300 amu.

SIM mode : Détecte jusqu’à 30 en même temps, et jusqu’à 50 groupes de 30 masses.

Détection & traitement des données:

Le détecteur sert à mesurer le nombre d’électrons et à amplifier le signal pour atteindre une

bonne sensibilité. Le signal est enregistré sous forme de spectre de masse.

Le spectre de masse représente en ordonnée l’abondance des pics (en %) et en abscisse les rapports masse sur charge (m/z).

 DATABASE : NIST02 et WILEY 7 .

 

Les applications au niveau du CRAPC par la GC MS :

 

– DOSAGE ET QUANTIFICATION DE LA NICOTINE PAR GCMS (Fig: left)

– INDUSTRIELLES :cosmetique, parfumerie – parfums, produits parfumes, huiles essentielles; aromes

(Fig. Middle).

РEnvironnement : Analyse des polluants organiques volatils et semi-volatils COV ; HAP ; alcanes, dosage et identification des pesticides par la m̩thode SIM.

AUTOLAB METROHM  PGStat302N 

Electrochemistry is the relationship between chemistry and electricity. It describes the chemical phenomena coupled with reciprocal exchanges of electrical energy. Electrochemistry includes all technologies and techniques derived from its scientific work, such as electrolysis, corrosion, batteries, fuel cells, accumulators, and electrodeposition.

Electrochemical reactions are the phenomena that take place at the interface of two conducting systems (electronics: electrodes, ionic: solutions) during charge transfer composed of one or more electrons. These charge transfers are accompanied by changes in the oxidation states of the materials (oxidation or reduction) and therefore their physico-chemical nature (metal deposition, gas evolution, formation of radical species, coupled chemical reactions among others). The set of elementary reactions can thus reach a high level of complexity. Electrochemistry makes it possible to better understand the phenomena of redox and corrosion.

Electrochemistry applications are generally classified into the following categories:

Electrosynthesis, Surface Treatment and Corrosion, Storage and Energy Conversion, Methods of Analysis and Measurement, Environment and Biology.

CRAPC has Autolab/PGSTAT302N.

Autolab/PGSTAT302N is a modular high power potentiostat/galvanostat with a maximum current of 2 A (with BOOSTER20A 20 A) and compliance voltage of 30 V. The PGSTAT302N is the benchmark for high speed digital potentiostat/galvanostat instruments.

With a bandwidth of over 1 MHz, the PGSTAT302N can be fitted with all the available Autolab modules, making it not only the fastest but also the most versatile member of the Autolab N series. Analog and digital inputs and outputs for interfacing and controlling external devices are available.

Electrochemistry and the environment

Electrochemistry and the environment emphasizes the increasing interactions between electrochemistry and the sciences dedicated to environmental studies. It deals with analytical electrochemistry for the environment, the fuel cell, the storage of photovoltaic electricity and the electrochemical treatment of polluted soils.

Electrochemistry and health

Electrochemistry and health shows how the use of an electrical signal applied in the form of high-voltage pulses (electroporation permeabilizing lipid bilayers) or low-intensity pulses (iontophoresis) offers a definite potential for the administration of conventional drugs or biotechnological origin. Thus, electroporation applied after local injection of a plasmid (electrotransfer) increases transfection efficiency and iontophoresis increases transdermal drug delivery, including peptides or oligonucleotides. In addition, electrochemotherapy (combination of a  local treatment with a non-permeant cytostatic followed by electrical impulses) locally eliminates tumors.

Electrotransfer and iontophoresis are therefore a promising alternative for administering drugs and genes. They are also a major therapeutic application of electrochemistry.

We can also find the biosensor as the best application in the health field for detection of lot of      diseases.

Electrochemistry and nanoscience

Electrochemistry and nanoscience it intervenes on several levels, to modify, to shape, to characterize and to study nanostructures and nano-objects. In return, nanosciences offer a very rich field of applications of electrochemical methodologies.

The largest application in electro chemistry either in industry or scientific research is corrosion study wich inform us about :

  • Water analyzes
  • Analysis and control of corrosion
  • Control of  surfaces
  • Study of electrolyte and its impact on corossion
  • Realization and control of coatings

X-Ray fluorescence Spectrometry XRF

 

X-ray fluorescence spectrometry is an elementary analysis technique that identifies and determines most of the chemical elements who compose the sample. This technique can be used for a variety of materials: minerals, ceramics, cements, metals, oils, water, glasses … in solid or liquid form.

It allows the analysis of all chemical elements from Beryllium (Be) to Uranium (U) in concentration ranges ranging from a few ppm to 100%, with precise and reproducible results.

The sample to be analyzed is placed under an X-ray beam. Under the effect of these X-rays, the atoms constituting the sample pass from their ground state to an excited state. The excited state is unstable, the atoms then tend to return to the ground state by releasing energy in the form of X photons in particular. Each atom, having electronic configuration, will emit photons of energy and wavelength own. It is the phenomenon of X-ray fluorescence that is a secondary ray emissionX, characteristics of the atoms that compose the sample. The analysis of this secondary X-ray allows both to know the nature of the chemical elements present in a sample with their mass concentration.

The equipment that exists at CRAPC is wavelength dispersive (WDS) in this type of equipment, to identify the different X-rays emitted by the sample is interspersed in their path a crystal analyzer. The device uses the crystalline solids property to be able to diffract X-rays under certain conditions. A crystalline solid can be seen as the three-dimensional periodic repetition of elements (atoms or molecules) and be characterized by reticular planes spaced a distance d passing through the centers of these elements.

In order to be able to determine the mass concentration of each chemical element contained in a sample from the measurement of the intensity of the diffracted lines, it is necessary to have previously carried out a calibration of the spectrometer. 

It is a question of establishing from the measurement of standards calibration lines for each chemical element to be determined which relate the intensities measured as a function of the concentration.

CRAPC has a Rigaku ZSX Primus II who delivers a rapid quantitative determination of major and minor atomic elements, from beryllium (Be) to uranium (U), in a wide variety of sample types-with minimum standards.

It has an innovative configuration of the optics-top. Never again worry about the path of a contaminated beam or downtime due to maintenance of the sample chamber

-Optical-top geometry eliminates cleaning worries and increases uptime.
-Analysis of elements from Be to U
-Optical tube located above minimizes contamination issues
-Small footprint, uses the least valuable space in the laboratory
-Micro analysis to analyze samples as small as 500 μm
30μ tube provide superior performance of lightweight elements
-Mapping function for topography / elemental distribution

At the end we can say that X-ray fluorescence spectrometry is among the best methods of chemical analysis (qualitative and quantitative) in industry and research.

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CAPACITY STENGTHENING FRAMEWORK 
CNRST - 46 Boulevard Mohamed V, Alger
DGRSDT - 24 Mohamed Guassem, Alger
LRI-Annaba, Université Badji Mokhtar