Instrumental Methods of Analysis
Code
10709
Academic unit
Faculdade de Ciências e Tecnologia
Department
Departamento de Química
Credits
6.0
Teacher in charge
Carlos Lodeiro Espino
Weekly hours
4
Teaching language
Português
Objectives
The curricular unit aims to provide the fundamentals in the field of physical chemistry techniques commonly used in the laboratory: spectroscopy and electrochemistry, but sometimes only in optics user. It is thus intended that the student understand the phenomena in its origin enabling them to intervene in the future, both in terms of technical development or in the interpretation of experimental data.
As specific objectives: i) the concept of electromagnetic radiation interaction with matter; ii) fundamentals of atomic and molecular spectroscopy with a focus on UV-Vis, IR and Fluorescence iii) basics of nuclear magnetic ressonance spectroscopy; iv) fundamentals of electrochemical methods; v) Mass Spectrometry; VI) Ther modern techniques as confocal and electronic microscopy.
Prerequisites
It’s advisable that the student get approval in basic chemistry lectures as Introduction to physical chemistry, analytical Chemistry and basic knowledge in Organic and Inorganic Chemistry.
Subject matter
I Introduction to optical methods
Electromagnetic radiation : radiation -matter interaction ; Equation of energy conservation ;
Spectroscopy and regions of the electromagnetic spectrum; associated transitions;
Units and conversions in spectroscopy
Radiation transmission : electric dipole , induced dipole moment , polarizability , refraction , dispersion , Rayleigh scattering
Absorption of electromagnetic radiation , atomic absorption ; Molecular Absorption ( UV , Vis , IR , Raman )
The equipment in spectroscopy : Quantitative aspects of molecular absorption spectra UV - Vis , Transmittance , Absorbance - OD ; Lambert Law , Beer''''s Law ; molar absorptivity ; limitations and deviations from the quantitative analysis
Structural features of the absorption spectra : Absorption of radiation to the hydrogen atom ; Absorption of radiation: the species H2 +
Theory of molecular orbitals : Distribution in electronic molecular orbital s and p ; Diagram energy levels of molecular orbitals ; Examples of types of transition for some molecules and their spectra; Soret band.
Selection rules : The harmonic oscillator ; Quantization of vibrational levels ; Morse curves , the Franck - Condon principle
Examples of absorption spectra for situations where the excited state of equilibrium has distances lower than or equal to the ground state
singlet and triplet states , allowed and forbidden transitions .
Emission spectra , fluorescence , phosphorescence
Infrared Spectroscopy : Concepts of electric dipole , harmonic oscillator and anharmonic revisited ; modes of molecular vibrations ; Examples of IR spectra and characteristic bands ;
Raman spectroscopy
Nuclear magnetic resonance and nuclear spin magnetization ; ressonance Condition; Chemical shift , Factors affecting the intramolecular chemical shift , magnetic anisotropy , spin- spin coupling
Forecasting exercises spectra of simple molecules
II Introduction to electroanalytical methods
Notion of the electrochemical cell and its schematic representation ; faradaic and non-faradaic current; liquid - liquid junction potential .
Potential of an electrode : standard hydrogen electrode and other reference electrodes; Calculation of the thermodynamic potential of an electrochemical cell ; Use of molar concentration vs. activity , the activity coefficients and ionic strength ; Calculation of activity coefficients ; notion of formal potential ; Influence of resistance in an electrochemical cell potential , polarization and its importance for studying electrochemical methods .
Potentiometry : reference electrodes ; quirks of their construction and use; Examples of calomel electrodes and silver / silver chloride ; membrane electrodes , the pH electrode .
Voltammetry : Introduction to cyclic voltammetry ; shape of a voltammogram and concentration profiles ; reversible reactions and reversibility ; calculations of diffusion coefficients , formal reduction potential and number of electrons exchanged ; chemical reactions coupled to electrochemical processes .
III Introduction to spectrofotometric methods
IV Other Modern Analytical Methods: Confocal and Transmision Electron Microscopy.
Bibliography
1 - Physical Chemistry , J.De Paula, P.W. Atkins, W. H. Freeman; 7th edition (December 7, 2001)
2 - Molecular Fluorescence: Principles and Applications, B. Valeur, Wiley-VCH; 1 edition (October 11, 2001)
3 - Quantitative Chemical Analysis, D. C. Harris, W. H. Freeman; 6th edition (July 15, 2002)
4 - Fundamentals of Electro-Analytical Chemistry, P. M. S. Monk, John Wiley & Sons; 1 edition (March 22, 2001), chapter VI
Notes supplied by the teacher
Teaching method
Lectures supported by data show projection of figures/plots/text included either in the documentation supplied directly by the teacher or in the recommended bibliography.
Problem solving sessions
Computer sessions with presentation of i)linear and non-linear regression, ii) worksheet to evaluate standard deviation that affects linear regression
Laboratory sessions with 4 different exsperiments.
Evaluation method
The continuous evaluation has 2 components: theoretical (T) and practical (L). The final classification is calculated according:
Final classification = 25% x L + 75% T
To get approval in the theoretical part it is necessary to obtain positive classification in the final test or official examination.
The laboratorial classification results from:
i) the evaluation and discussion of one laboaratorial report
ii)evaluation of questionaries of the remaining experimental works
iii) laboratorial performance
Presentation of a working group Subject.