37478 - Analytical Chemistry of Organic Materials

Learning outcomes

At the end of the course the student will acquire knowledge on analytical techniques based on chromatography and mass spectrometry for the characterization of organic materials in cultural heritage, including sample pre-treatment procedures and critical aspects of data interpretation. At the end of lessons and informatic laboratory concerning data processing, the student knows how to choose and apply the most appropriate method for performing the statistical analysis.

Course contents

Unit 1. The element carbon (isotopes, allotropes) and its compounds; elemental composition (graphite and charcoal), atom connectivity (structural formula, isomers, functional groups). Classification of organic materials. Chemical properties relevant in chemical analysis: molecular mass, polarity(lipophilic and hydrophilic substances), volatility. Basic concepts of the analytical procedure. Sample treatment: solubilisation, solvent extraction (definition, solvent selection), chemical degradation (hydrolysis, methanolysis), thermal degradation (pyrolysis). Chromatography, definition, types of chromatography (liquid chromatography, reversed, normal, adsoprtion, partition, paper, column, thin layer; gas chromatography, high temperature GC), retention and selectivity, retention time, peak area, calibration. Mass spectrometry, types of ions, ionisation methods, mass spectra, quadrupole. Hyphenated techniques: HPLC-ESI (APCI)-MS, GC-QMS, GC-IRMS, Py-GC-MS. Strategies of identification of organic materials: relative distribution (chemical fingerprinting), compound ratios, molecular markers (examples). Isotope ratios 13C/12C, 15N/14N (delta notation). Confounding factors: degradation processes, mixtures, matrix effects, analytical artefacts. Analysis of lipids, carbohydrates, proteins. Unit 2. Gauss distribution; confidence interval; significant figures; significance test; calibration of chemical-analytical methods: external standard method, standard addition method, internal standard method; quality parameters of a chemical-analytical measurement; propagation of technical and statistical errors. Multivariate statistical analysis: principal component analysis, multivariate classification and regression. Multivariate regression MLR.

Readings/Bibliography

Lesson slides in IOL. Laboratory papers.

- General concepts: J.S.Mills e R.W.White, The Organic Chemistry of Museum Objects, 1996.

- Specific examples/ advanced techniques:Organic Mass Spectrometry in Art and Archaeology. MP.Colombini, F. Modugno Eds, Wiley and Sons, 2009.

- J.N. Miller, J.C. Miller, Statistics and Chemometrics for Analytical Chemistry, Pearson Education, 2010.

- Richard G. Brereton, Applied Chemometrics for Scientists, Wiley, 2007.

Teaching methods

PRE-REQUISITE:to give the exam it is compulsory to have passed the exam of the course CHEMISTRY FOR RESTORATION

Videoprojection of power point presentation. Use of software for Chemometrics: Microsoft Excel , CAT. Concepts are illustrated by examples and case studies in the field of cultural heritage.

The participation is mandatory to Moduli 1 e 2 di formazione sulla sicurezza nei luoghi di studio, [https://elearning-sicurezza.unibo.it/] in e-learning mode.

Assessment methods

Oral examination. The student will be asked to describe the analytical concepts and definitions described in the class and slides. The knowledge of the chemical structure of the most important organic substances described in the course is mandatory.

Teaching tools

Lecturing, tutorials, utilisation of data base for searching analytical methods, exercises from case study.

Office hours

See the website of Daniele Fabbri

See the website of Dora Melucci