67031 - Instrumental Analytical Chemistry and Laboratory Laboratory

Learning outcomes

The aim of the course is to give students the ability to identify and understand the elements that constitute the "analytical process": 1) definition of the objective; 2) sampling; 3) interference removal / preconcentration; 4) measurement; 5) evaluation of results. Faced with a specific analytical problem, they must be able to trace the resolution by a complete assessment of the five steps mentioned above. In particular they will be able to identify the characteristic property (ies) that can be usefully exploited for the analytical instrumental determination of one or more analytes, even if present simultaneously, in samples of moderate complexity, and to choose the most suitable method for analysis

Course contents

Knowledge and comprehension

At the end of the course the students will know:

• the statistical methods for the treatment of the error, the main significance tests, the techniques for the construction of calibration functions, the definition of limit of detection and quantification
• the principles of partition equilibria and of separation processes
• the basic elements of electronic signal processing
• the operating principles and the instrumental arrangements of the most common analytical instruments (Potentiometers, Conductivity meters, Chromatographs, UV-VIS spectrophotometers and Atomic Absorption)
• the parts and the structure of an analysis report

  At the end of the course the students will have comprehended:

• the role of partition equilibria in the processes of interferences removal
• the role of partition equilibria in chromatographic processes
• the role of UV-Vis electromagnetic radiation in the production of analytical signals
• the issues related to the execution of direct and indirect potentiometric measurements (relationship between measured potential and redox species activity, calibration curve, detection limit)
• the relationship between the measurement of the conductivity of a solution and the quantitative determination of one or more ionic species

Abilità e Competenze

At the end of the course the student will be able to:

• write an analysis report
• build and use linear and non-linear calibration curves
• to recognize when it is necessary to use the method of the standard additions for the quantitative determination of analytes
• use and correctly interpret the measurements obtained in an analytical determination
• identify the elements of the "analytical process" in an analytical procedure
• evaluate the goodness of an analytical method in relation to its objectives
• critically compare and evaluate the performance of different analytical approaches for the analysis of the same sample
• design analytical determinations in non-complex matrices, identifying the most suitable procedures and instruments.

Argomenti del corso

Description of the steps of the analytical process. Main components of an analytical instrument. Introduction to sampling and sample storage problems. The "analysis report" and the "laboratory report"

Statistics of instrumental analysis. Signal to noise ratio. Effect of digital sampling on the response. Calibration and regression curves. Standard addition. Confidence interval of a concentration obtained from a calibration line and by the addition method. Calibration curves in the case of deviations from linearity. Detection limit and sensitivity of instrumental chemical analysis. Quantification limit. The error in the analytic process.

Partition equilibrium between phases. Liquid-liquid extraction. Percent of extraction. Effect of secondary equilibria on the distribution and their use for the isolation of species. Main solvent extraction techniques.

Electrochemical techniques. Electrical conductivity of electrolyte solutions. Specific conductivity, equivalent conductivity and conductivity equivalent to infinite dilution. The conductivity-meter and its use. Direct conductivity measurements. Conductimetric titrations (acidimetric, precipitation, complexometric). Ion-selective electrodes and reference electrodes. Potentiometric methods with ion-selective electrodes and metal indicator electrodes. Gran method for the identification of the end titration point.

Theoretical bases of chromatographic separations, counter current extraction. Mechanism of the column chromatographic process. The phenomenon of band broadening in chromatography and its phenomenological justifications: plate theory and kinetic theory. Instrumental chromatographic techniques: Gas chromatography and high-performance liquid chromatography (HPLC). Evaluation of the efficiency of a chromatographic column. Main chromatographic parameters. Quality of chromatographic separations. Qualitative analysis: relative retention time and retention indices. Quantitative analytical methods in chromatography. Characterization of the chromatographic phases (Rohrschneider-McReynolds indices).

UV-Vis Molecular absorption spectrometry: principles, instrumentation, operating conditions and quality control of spectrophotometric measurements. Construction of the instrumental response curve and the Bouguer-Lambert-Beer law. Analysis of mixtures. Flame atomic absorption spectrometry: principles, instrumentation, hollow cathode lamps, Boltzman's law. Qualitative and quantitative methods in flame analysis.

The course includes many laboratory experiences, some of which will be design by the students, under the guidance of teachers.

It is recommended to complete the preparation for the exam with the study of textbooks . For each topic, specific chapters of the texts listed below (which the student can freely choose) will be suggested to be studied and will be and considered as part of the course content.

KNOWLEDGE AND ABILITY REQUIRED

In general, the knowledge and skills acquired in the courses of: Mathematics, Physics, General Chemistry, Physical Chemistry 1 and Analytical Chemistry with Laboratory are required.

In particular, students must:

• mastering the principles of chemical equilibrium and the graphic and mathematical treatment of simultaneous equilibria
• perform stoichiometric calculations of moderate complexity
• possess elementary notions of optics and elementary algebra
• be able to handle simple mathematical functions
• know the nomenclature of the most common chemical compounds
• have gained a good skill in the use of laboratory glassware and in the performance of volumetric titrations

Readings/Bibliography

There are many well done books useful to deal with the contents of the course

1. D.C. Harris, Chimica Analitica Quantitativa, Zanichelli, (2017)
2. M.Castino, E. Roletto, Statistica applicata. Trattamento dei dati per studenti universitari, ricercatori e tecnici. Piccin, 1999 (ISBN: 9788829909353)
3. J.C. Miller and J.N. Miller, Statistics and Chemometrics for Analytical Chemistry, 6^th ed., Prentice Hall (UK), 2010
4. D.A. Skoog, D.M. West, F.J. Holler, S.R. Crouch, Fondamenti di Chimica Analitica, III Ed., Edises, 2009
5. David Harvey, Modern Analytical Chemistry, McGraw-Hill Education, [https://www.bookdepository.com/publishers/McGraw-Hill-Education-Europe] 1999

The textbook by Harvey (4) is available in the web: (last check 30 June 2019): http://dpuadweb.depauw.edu/harvey_web/eTextProject/AC2.1Files/AnalChem2.1.pdf

Teaching methods

The lectures will be accompanied by an extensive experimental and practice design activity, organized for small work groups and led by teachers. Such activities will be based on the resolution of simple case studies that will address the topics of the course. During the course students will be asked to deliver individual or group papers related to theoretical topics and laboratory experiences. These papers will be evaluated by the teachers, but will not have a weight in the final grade. They therefore constitute an additional tool to complete their preparation on the course topics.

For the resolution of case studies, sheets, worksheets and online supports will be provided.

All teaching materials (slides, cards and in-depth material, exercises) will be shared on the Moodle platform.

h activities will be based on the resolution of simple case studies that will address the topics of the course. During the course students will be asked to deliver individual or group papers related to theoretical topics and laboratory experiences. These papers will be evaluated by the teachers, but will not have a weight in the final grade. They therefore constitute an additional tool to complete their preparation on the course topics.

For the resolution of case studies, sheets, worksheets and online supports will be provided.

All teaching materials (slides, cards and in-depth material, exercises) will be shared on the Moodle platform.

Assessment methods

During the course students will be asked to deliver individual or group papers related to theoretical topics and laboratory experiences. These papers will be evaluated by the teachers but will not have a weight in the final grade. They therefore constitute an additional tool to complete the preparation on the course topics.

The verification of learning takes place through: an individual laboratory report, an individual practical test, and the final written exam.

Individual laboratory report. Within the last week of the lab, each student will be assigned, by drawing, the experience on which an INDIVIDUAL report is required. The score of such a report is based on an evaluation grid delivered to the students at the beginning of the course and it concurres to the 40% of the overall evaluation of the laboratory.

Practical test. The practical test is carried out during the last week of the course and it is not normally allowed to repeat it. The test involves the design and execution of a simple analytical determination using one of the instrumental techniques used during laboratory experiments. During the test, the student can consult his laboratory notebook, laboratory reports and textbook. It is compulsory to have a scientific calculator (the one available on tablet or mobile devices is not allowed) and the necessary to trace diagrams on graph paper (pencil, ruler, team, rubber, pencil sharpener). It is not allowed to talk or consult with the other students during the test.

The practical test last 3 hours.

Depending on the circumstances, the practical test could take place in "remote" mode. In this case, students will be provided with real data on which to carry out their own calculations

At the end of the practical test the student must present a brief report (a model will be provided) and the analytical result with confidence interval. The evaluation of the relationship will be based on: a) the adequacy of the analytical procedure with respect to the problem posed; b) the correct preparation of the necessary materials and solutions; c) the correctness of the experimental operations; d) the correct expression of the analytical result; e) the proximity of the given result to the "true" one.

The score of the practical test contributes to the 60% of  overall laboratory activity evaluation.

The score obtained in the individual report and in the practical test is converted into thirtieths and contributes to the overall evaluation for 40% of the total

The written exam test consists of a maximum number of 10 items between: a) True / False questions; b) multiple choice questions; c) open-ended questions; c) resolution of problems and exercises related to the acquired knowledge and skills acquired on the theoretical, practical and applicative contents of the course. The test may also contain questions that relate to previous knowledge and not explicitly covered in the course but essential for understanding the contents of the course.

The written test last a maximum of 3 hours.

During the written test, the use of textbooks, the periodic table and the lesson notes (or slides) is not permitted. The laboratory notebook is allowed to be consulted. It is compulsory to have a scientific calculator (the one available on tablet or mobile devices is not allowed) and the necessary to trace diagrams on graph paper (pencil, ruler, team, rubber, pencil sharpener). The material on which to write the tests (protocol sheets, graph paper, etc.) will be made available by the teachers.

The evaluation of the written test is expressed in thirtieths and contributes to the overall evaluation for the 60% of the total.

The exam, if passed, retains its validity, at the discretion of each student, for the sessions scheduled for the academic year in which the course took place. However, it loses validity upon delivery for correction to the teacher of the test done during a subsequent appeal. A maximum of two positive ratings can be rejected. A second test can be taken only if at least 15 days have elapsed since the previous one. It is not allowed to take more than two tests for each exam session (if a higher number is offered).

Teaching tools

All the learning material (slides, cards and in-depth material, exercises) will be shared on the "Virtuale" platform.

Office hours

See the website of Sergio Zappoli

See the website of Andreas Stephan Lesch

See the website of Erika Scavetta