C8587 - ANALISI DEGLI INQUINANTI ORGANICI

Learning outcomes

The course offers students the opportunity to consolidate and expand their knowledge of Organic Chemistry II, applying it to one of today’s most relevant and pressing topics: the study and analysis of organic pollutants in the environment. Special emphasis will be placed on advanced spectroscopic and spectrometric techniques for the identification and characterization of organic compounds, including Nuclear Magnetic Resonance (NMR) Spectroscopy and Mass Spectrometry (MS), with practical examples related to the analysis of pesticides, polycyclic aromatic hydrocarbons, and other emerging contaminants. The course aims to provide not only a solid theoretical foundation but also a practical perspective on how organic chemistry contributes to the assessment and monitoring of environmental pollution, offering valuable preparation for students interested in careers in research, environmental science, and chemical analysis.

Course contents

PREREQUISITES

Basic knowledge of organic chemistry, organic functional groups, and fundamental concepts of physical chemistry.

Course Program NMR Spectroscopy

Spin magnetic moment, orientation in a magnetic field, and Larmor frequency. Sensitivity of the NMR experiment. Selection rules for atomic nuclei. CW and FT acquisition techniques. Vector description of magnetization. Magnetization vector and radiofrequency pulses.

¹H NMR spectroscopy. Theory of chemical shift and selection of reference standards. Signal integration. Theory of spin-spin coupling, spin systems, and coupling patterns in AX, AMX, AX₂, AX₃, and ABX₃ systems. Interpretation of experimental aliphatic spectra. Chemical and magnetic equivalence, strongly coupled spectra. Analysis of ortho-, meta-, and para-substituted aromatic spin systems.

¹³C NMR spectroscopy. Fully coupled spectra and broadband-decoupled spectra. Integration of carbon spectra. DEPT experiments for NMR signal assignment.

Theory of dipolar relaxation. NOE spectroscopy. Difference NOE and transient NOE techniques. Qualitative interpretation of NOE spectra for the determination of molecular geometry.

Mass Spectrometry

Fundamental principles of mass spectrometry: nominal mass and exact mass. Identification of the molecular ion. Determination of molecular composition from high-resolution mass spectra. Isotopic patterns of carbon, bromine, and chlorine.

Ionization methods: electron impact (EI), electrospray ionization (ESI), and MALDI. Mass analyzers: magnetic sector, quadrupole, ion trap, time-of-flight (TOF), and FT-ICR. Isotopic composition. Definition of primary and secondary fragmentation. Classification of primary fragmentation processes. Fragmentation mechanisms and characteristic ions.

Atropisomerism

Introduction to axial chirality. M and P nomenclature. The boundary between configuration and conformation.

Readings/Bibliography

Robert. M. Silverstein et al

IDENTIFICAZIONE SPETTROMETRICA DI COMPOSTI ORGANICI

Terza Edizione

Casa Editrice Ambrosiana

ISBN 978-88-08-18350-7

 

A. Randazzo, A. Mangoni, G. Giorgi, R. Gobetto

ANALISI STRUTTURALE DELLE MOLECOLE

Loghìa

ISBN 978-88-95122-67-0

Teaching methods

Lectures will be delivered by the teacher using slide presentations and molecular models. Approximately one-fifth of the lessons hours will be devoted to in-class exercises carried out under the guidance of the teacher.

Assessment methods

The examination consists of a single written test to be taken during the official examination sessions. The test is based on a structural elucidation exercise.

The structural elucidation exercise requires students to determine the structure of an unknown organic compound using experimental NMR and mass spectrometric data. The correct structure must be identified from a set of chemical structures provided in the examination paper.

During the final written examination, students are permitted to consult textbooks, lecture notes, handouts, and personal notes. The use of devices capable of connecting to the Internet (e.g., tablets, smartphones, and similar devices) is strictly prohibited.

Registration through the “Alma Esami” system is mandatory in order to take the written examination and must be completed within the prescribed deadlines, which are strictly enforced.

Teaching tools

All lecture slides presented in class, the exercises completed during the lectures, and a selection of past examination papers are made available at the beginning of the course through the “Online Teaching” (Insegnamenti On Line) platform, accessible via Virtuale [https://virtuale.unibo.it] .

Office hours

See the website of Michele Mancinelli