67031 - Instrumental Analytical Chemistry and Laboratory Laboratory

Learning outcomes

The course aims to develop in students the ability to identify and understand the elements that constitute the "analytical process": 1) definition of the objective; 2) sampling; 3) removal of interferences/concentration; 4) measurement; 5) evaluation of results. Faced with a specific analytical problem, they should be capable of outlining its resolution by fully defining the five aforementioned steps. In particular, they will be able to identify the characteristic properties that can be effectively exploited for the instrumental analytical determination of one or more analytes, even if present simultaneously, in samples of moderate complexity, including real samples, and choose the most suitable method for the analysis.

Course contents

Knowledge and Understanding

By the end of the course, students will have acquired knowledge of:

• statistical methods for error treatment, the main significance tests, techniques for constructing calibration functions, the definitions of limit of detection and limit of quantification, and their application to instrumental analytical determinations;
• the principles governing partition equilibria and separation processes;
• the operating principles and instrumental configurations of the most commonly used analytical instruments, including potentiometers, conductivity meters, gas chromatographs, high-performance liquid chromatographs, UV–Vis spectrophotometers, and atomic absorption spectrometers;
• the components and structure of an analytical report.

Students will also have developed an understanding of:

• the role of chemical equilibria—including acid–base, complexation, redox, and partition equilibria—in processes used to remove interferences;
• the role of partition equilibria in chromatographic processes;
• the interaction of UV–Vis electromagnetic radiation with matter in the generation of analytical signals;
• the issues associated with direct and indirect potentiometric measurements, including the relationship between measured potential and analyte activity, calibration curves, and limits of detection;
• the relationship between the electrical conductivity of a solution and the quantitative determination of one or more ionic species.

Skills and Competences

By the end of the course, students will be able to:

• prepare an analytical report;
• construct and use calibration curves, including non-linear calibration curves;
• identify when the standard-addition method is required for the quantitative determination of analytes;
• correctly use and interpret measurements obtained during an analytical determination;
• identify the individual stages of the analytical process within an analytical procedure;
• assess the suitability and performance of an analytical method in relation to its intended purpose;
• compare and critically evaluate the performance of different analytical approaches used to analyse the same sample;
• design analytical determinations for relatively simple matrices, selecting the most appropriate procedures and instrumentation.

Course Content

Description of the stages of the analytical process. Main components of an analytical instrument. Introduction to issues related to sampling, sample collection, and sample preservation. The analytical report and the laboratory report.

Statistics in instrumental analysis. Signal-to-noise ratio. Effect of digital sampling on instrumental response. Calibration curves and regression equations. Standard addition. Confidence intervals for concentrations determined from a calibration line and by the standard-addition method. Limit of detection and sensitivity in instrumental chemical analysis. Limit of quantification. Error in the analytical process.

Partition equilibria between phases. Liquid–liquid extraction. Percentage extraction. Effects of secondary equilibria on partitioning and their use in the isolation of chemical species. Main solvent-extraction techniques.

Theoretical foundations of chromatographic separations and counter-current extraction. Mechanism of column chromatography. Chromatographic band broadening and its phenomenological interpretation: plate theory and kinetic theory. Instrumental chromatographic techniques: gas chromatography and high-performance liquid chromatography (HPLC). Evaluation of chromatographic column efficiency. Main chromatographic parameters. Quality of chromatographic separations. Qualitative analysis: relative retention time and Kováts retention indices. Quantitative methods in chromatography. Characterisation of chromatographic stationary phases using the Rohrschneider–McReynolds indices. Introduction to solid-phase extraction and purification techniques, including SPE and SPME.

Electrochemical techniques. Electrical conductivity of electrolyte solutions. Specific conductivity, equivalent conductivity, and equivalent conductivity at infinite dilution. The conductivity meter and its applications. Direct conductivity measurements. Conductometric titrations, including acid–base, precipitation, and complexometric titrations. Ion-selective electrodes and reference electrodes. Potentiometric methods using ion-selective electrodes and metallic indicator electrodes. The Gran method for determining titration end points.

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, and the Boltzmann law. Qualitative and quantitative analytical methods using flame atomisation.

The course includes at least one laboratory experiment integrating several analytical techniques. Under the supervision of the teaching staff, students will be partly responsible for designing the experimental work.

Students are reminded that studying the recommended textbooks is essential for adequate preparation for the examination. Specific chapters from the textbooks listed in the “Texts/Bibliography” section will therefore be indicated for each topic covered. Students may freely choose among the recommended textbooks. The material contained in these textbooks is consequently an integral part of the course content.

Knowledge and Skills Required to Undertake the Course

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

In particular, students must:

• be able to apply the principles of chemical equilibrium in moderately complex contexts and fully understand their effects on the progress of chemical processes;
• be able to represent, both graphically and mathematically, situations in which several chemical equilibria operate simultaneously;
• confidently perform stoichiometric calculations of moderate complexity;
• possess basic knowledge of optics and algebra;
• be able to work with simple mathematical functions;
• be able to represent experimental trends correctly using Cartesian plots;
• be familiar with the use of spreadsheets and their main functions;
• know the nomenclature of the most common organic and inorganic chemical compounds;
• have developed a reasonable level of proficiency in the use of laboratory glassware and in carrying out volumetric titrations.

Readings/Bibliography

A wide range of authoritative and comprehensive textbooks covering the course content is available, many of which can be consulted through the University libraries.

Students may find the following publications useful:

1. D.C. Harris, Chimica Analitica Quantitativa, Zanichelli, 2017.
2. M. Castino and 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, 6th ed., Prentice Hall, UK, 2010.
4. D.A. Skoog, D.M. West, F.J. Holler and S.R. Crouch, Fondamenti di Chimica Analitica, 3rd ed., Edises, 2009.
5. David Harvey, Modern Analytical Chemistry, McGraw-Hill Education, 1999.

Harvey’s textbook, listed as item 5, has been made available by the author as an open-access resource at the following link (last accessed on 20 February 2023):

http://dpuadweb.depauw.edu/harvey_web/eTextProject/AC2.1Files/AnalChem2.1.pdf

Teaching methods

Lectures will be integrated by parallel laboratory activities, organised in small working groups and supervised by the teaching staff. These activities will focus on the practical application of the topics covered during the course, as well as on the active evaluation and adaptation of simple analytical methods to be applied to samples of different types.

The aim is to ensure that each member of the working group acquires sufficient skills to undertake the individual laboratory test included in the final examination (see below).

For this reason, before entering the laboratory to carry out an experiment, each student is expected to study the theoretical and practical aspects of the activity independently, also through active interaction with the other members of their group.

Supplementary materials and analytical procedures required for the laboratory activities will therefore be made available well in advance on the “Virtuale” learning platform, together with all other teaching materials, including lecture slides, worksheets, exercises, and additional study resources.

 

Safety in Study and Work Environments

In view of the types of activities and teaching methods adopted, participation in this course requires all students to complete Modules 1 and 2 in e-learning mode and to attend Module 3, which provides specific training on health and safety in study environments.

Information on the dates and attendance arrangements for Module 3 is available in the dedicated section of the degree programme website.

Assessment methods

Learning outcomes will be assessed through the evaluation of laboratory activities, by means of an unknown-sample test, and a final written examination.

Students are reminded that attendance at laboratory activities is compulsory, as they constitute an integral part of the course.

Given the limited number of laboratory sessions, any absence must be duly motivated and justified, for example by providing a medical certificate.

Laboratory attendance is certified by participation in at least 80% of the scheduled activities and by completion of the laboratory assessment.

Laboratory Test. Laboratory activities will be assessed on a thirty-point scale. The assessment will be based on the results obtained in an individual instrumental analytical determination of an unknown sample, accompanied by a short report describing the procedure followed and the results obtained.

During the laboratory test, students may consult their own laboratory notebook, but they may not access any resources available on the internet.

The laboratory test accounts for 40% of the overall course grade.

Written Examination. The written examination consists of:

• a first section containing true/false and multiple-choice questions;

• a second section consisting of numerical problems and open-ended questions.

The written examination requires students to solve problems and exercises relating to the knowledge acquired and the skills developed in connection with the theoretical, practical, and applied content of the course.

The examination may also include questions relating to prior knowledge that has not been explicitly covered during the course but is essential for understanding or applying the course content.

The first section of the written examination is considered passed if the student achieves a score equal to or greater than 40% of the maximum score available for that section.

Passing the first section of the written examination, consisting of true/false and multiple-choice questions, is a prerequisite for proceeding to the second section.

During the second section of the written examination, students may consult one textbook of their choice.

Students must bring a calculator. Calculators available on devices such as tablets or mobile phones are not permitted. Students must also bring the materials required to draw diagrams on graph paper, where necessary, including pencils, a ruler, a set square, an eraser, and a pencil sharpener.

During the examination, students may use Microsoft Excel, and they are therefore advised to become familiar with its main functions.

The use of artificial intelligence tools during the written examination is prohibited. Any use of such tools constitutes a breach of academic integrity.

Any materials required to complete the examination, including examination paper and graph paper, will be provided by the teaching staff where necessary.

The written examination accounts for 60% of the overall course grade.

Calculation of the Final Grade

The final grade is determined by the weighted average of the laboratory grade, which accounts for 40%, and the overall written-examination grade, which accounts for 60%.

For example:

Laboratory grade: 30/30
Written-examination grade: 25/30

Final grade:

30 × 0.40 + 25 × 0.60 = 12 + 15 = 27/30

The laboratory test result remains valid indefinitely.

A passed written-examination result may be retained at the student’s discretion. However, the previous written-examination result ceases to be valid when the student submits a new examination paper for assessment during a subsequent examination session.

Students may reject no more than two passing grades.

A second examination attempt may be taken only if at least 15 days have elapsed since the previous attempt, unless the teaching staff grant an exception for duly justified reasons.

Students with Specific Learning Disabilities or Temporary or Permanent Disabilities

Students are strongly advised to contact the relevant University office well in advance:

https://site.unibo.it/studenti-con-disabilita-e-dsa/it

The office will propose any appropriate adjustments for the students concerned. Such adjustments must in all cases be submitted to the course instructor for approval at least 15 days in advance. The instructor will assess their suitability, also in relation to the intended learning outcomes of the course.

Teaching tools

The main form of support for learning consists of further study of the topics covered in class through specialist textbooks, some of which are listed in the bibliography, and through the reading of articles from the scientific and technical literature.

All teaching materials selected or produced by the teaching staff, including lecture slides, worksheets, supplementary materials, and exercises, will be made available on the “Virtuale” learning platform.

Office hours

See the website of Sergio Zappoli

See the website of Andreas Stephan Lesch

See the website of Erika Scavetta