ANALYTICAL CHEMISTRY II AND LABORATORY

The aim is to provide background information on instrumental analytical chemistry with specific reference to spectroscopy and electrochemistry.

Class and laboratory experiments.

Should teaching be carried out in mixed mode or remotely, changes with respect to previous statements may be introduced, in line with the outlined syllabus.

According to safety requirements linked to the pandemic, learning assessment may also be carried out online.

1. Spectroscopy:
Electromagnetic radiation: wave-particle dualism, photoelectric effect and diffraction, Heisenberg's principle. Electromagnetic spectrum. Refraction, refractive index, Snell's law, total internal reflection. Interaction of radiation with matter: reflection, transmission/absorption, diffusion (Rayleigh, Mie, Raman). Absorption and emission of radiation. Atomic absorption. Molecular absorption. Vibrational and rotational motions. Fluorescence, phosphorescence.

2. Molecular spectroscopy - UV-vis
Transmittance, absorbance, Beer's law. Limitations of Beer's law. Photometer and spectrophotometer. Single beam spectrophotometer, Double beam spectrophotometer. Sources. Wavelength selectors. Transducers: photovoltaic cells, photocathodes, photomultiplier tubes, series of diodes, charge injection, coupled charge.

3. Molecular spectroscopy - infrared
General characteristics. Harmonic and anharmonic oscillator, dipolar moment of transition. Molecular vibrational modes. Main IR signals: functional groups area, fingerprint area. Dispersion spectrophotometers. Fourier transform spectrophotometers: Time domain and frequency domain, Fourier transform, Michelson interferometer. Sources. Detectors. IR spectrum characteristics and interference. Cells for gas and liquid analysis. Solids analysis. Diffuse reflectance. Total attenuated reflectance. Microscopy.

4. Molecular spectroscopy - Raman
General characteristics. Raman effect. Polarizability. Comparison with IR spectroscopy. Raman signal strength. Depolarization ratio. Resonance-enhanced Raman Scattering. Surface-enhanced Raman Scattering. Sources. Dispersive and Fourier transform spectrometer. Raman microscopy.

5. Atomic spectroscopy
Instrumentation for atomic absorption, emission and fluorescence. Atomic absorption: sources, broadening phenomena of the spectral lines, temperature effect, methods for introducing samples, flame and thermoelectric atomization, interference. Atomic absorption instrumentation. Atomic emission spectrometry: inductively coupled plasma sources.

6. X-ray fluorescence:
Fundamental principles, X-ray emission, continuous and characteristic radiation, Moseley's law, fluorescence yield and competitive processes, selection rules, Siegbahn notation and IUPAC notation. Interaction of X-rays with matter. X-ray attenuation. X-ray absorption. Instrumental components: X-ray sources: X-ray tube, rotating anode tube, radioisotope sources, synchrotron light; detectors: gas filled, scintillation, solid state; pulse width selector. Energy dispersive X-ray fluorescence spectroscopy (EDXRF). Wavelength dispersion X-ray fluorescence spectroscopy (WDXRF). Outline: scanning electron microscope EDS / WDS, Particle induced x-ray emission (PIXE), Total reflection XRF (TR-XRF).

7. Mass spectrometry
Fundamental. Ion sources: ICP, EI, CI, FD, FAB. SIMS, LD-MS, MALDI, ESI. Mass analyzers: magnetic sector, quadrupole, time of flight, ion trap, ICR-MS, orbitrap. Mathieu equation, secular frequency, ion trapping, isolation, resonant excitation, SIM, MS / MS experiments, hyphenate techniques.

8. Electroanalytical methods
Galvanic cell. Electrode potential. Nernst equation. Electrolytic cell. Junction potential, salt bridge. Double electric layer. Electroanalytical methods. Ohmic potential. Electrode polarization: concentration, reaction, adsorption, desorption, crystallization, charge transfer, mass transport. Reference electrodes: hydrogen standard, calomel, Ag / AgCl. Indicator electrodes: first, second and third species, redox, membrane. Glass electrode: glass, interphase potential, asymmetry potential, calibration, alkaline and acid error. Combined glass electrode. Potentiometer, load error, voltage trackers. Main electroanalytical techniques: potentiometry, voltammetry, amperometry, coulometric methods.

9. Chromatographic methods
Classification of chromatographic methods. The chromatogram, the chromatographic peak, retention time, dead time, average migration speed of the solutes. The partition coefficient. The classical theory of theoretical plates and chromatographic efficiency. Gas Chromatography, High Performance Liquid Chromatography (HPLC). Analytical applications.

10. Statistics of repeated measures
Absolute and relative error. Types of errors. Accuracy and precision. Descriptive statistics: Histograms, Position parameters, mean, mode, median, quartiles. Parameters of
dispersion: variance, standard deviation, standard error, relative standard deviation. Probability distributions. Binomial distribution. Poisson Distribution, Normal Distribution, Standardized Normal Distribution, Student Distribution, χ2 Distribution, Fisher-Snedecor Distribution. Statistical Inference. Estimation theory, sample mean distribution, sample variance distribution. Central limit theorem. Confidence interval for the mean and for the variance and for the difference between two means. Hypothesis test. Significant figures. Correlation between variables, covariance, correlation coefficient. Linear regression: least squares method, standard deviation of the regression, slope, intercept and values ​​deduced from the line, goodness of fit, coefficient of determination. Matrix effect, recovery, method of standard additions. Sensitivity. Limit of detection and quantification.

11. Construction of a photometer for absorbance measurements:
Printed circuits. Symbols for electronic components. Ohm's law, Kirchhoff's law, voltage divider and current divider. Resistances and related conventions. Intrinsic and extrinsic semiconductors, p and n dopants. Diodes: forward and reverse polarization. Light emitting diode (LED). Photoresistors. Operational amplifiers: comparison devices, voltage trackers, inverting operational amplifiers.
Photometric determination of iron in aqueous solutions.

12. Potentiometric titrations
Determination of the phosphoric acid content in Coca-cola by potentiometric method.

-Class notes

-Skoog, Leary, “Chimica Analitica Strumentale”, Edises.

-Skoog, West, Holler, Crouch, “Fondamenti di Chimica Analitica”, Edises

-Rubinson, Rubinson, “Chimica analitica strumentale”, Zanichelli