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 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 analite's 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.

Skills and competences

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.

Course contents

 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 an integrated laboratory experience 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 20 February 2023): http://dpuadweb.depauw.edu/harvey_web/eTextProject/AC2.1Files/AnalChem2.1.pdf

Teaching methods

The lectures will be accompanied by an extensive experimental and practical project activity, organized for small working groups and guided by the teacher. The project aims to resolve simple real case studies that will address the teaching topics by developing simple analytical methods.In replacement of traditional laboratory "experiments", usually carried out in a sequence of topics and based on a more or less detailed "recipe", at the beginning of the teaching to the students, organized in heterogeneous groups of 4-5 students is assigned a problem, randomly selected from a shortlist of six. These problems offer the possibility for students to autonomously define the analytical problem they intend to address and solve, through the definition of their analytical procedure which will then be applied and tested in the laboratory. The only given condition is that the resolution of the assigned problem involves the use of at least two (if possible three) different instrumental techniques.

INTEGRATED DIGITAL TEACHING. The development of the approach described above requires intense preparatory work to be done before entering the laboratory with each working group. Each group, together with the "problem", is provided with basic materials (literature articles, book chapters, official methods) and a work agenda (in the form of Gannt). A reference teacher is also assigned to each group. Each working group has its room (channel) on Teams, where consultation files, shared work documents, materials found by the students, etc. are stored. At the start of the activity, meetings are scheduled to prepare the procedure(s), which will then be verified in the laboratory activity. These meetings will mainly be conducted on the Teams platform.

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

 

SAFETY IN STUDY AND WORK SPACES

Considering the types of activities and teaching methods adopted, the attendance of the lessons requires for all the students to partecipate to specific training on safety and health in study places: Modules 1 and 2 in e-learning mode and Module 3 in conventional mode. Information on dates and methods of attendance of Module 3 can be consulted in the specific section of the degree program website.

Assessment methods

Learning assessment takes place through the evaluation of both the laboratory activity and a final written exam.

Evaluation of laboratory activities

The laboratory activity involves the resolution of an analytical problem that is proposed to each working group in the first weeks of teaching. This activity is divided into a planning phase during which the groups (assisted by the reference teachers of the specific problem) will have to start outlining one or more possible strategies for solving the problem posed, defining a complete analytical procedure outline: type and number of tests to be carried out, necessary materials and tools, type and concentration of solutions to be prepared, division of tasks, etc...

• At the conclusion of this planning phase, the working group is expected to deliver a report in which the information useful for understanding the strategy chosen by the working group and the division of tasks among the members are summarized.

  The practical laboratory activities will be carried out by each group intensively over a week (indicatively the weeks of May will be used). Each group will have a complete and continuous week of work.

• At the end of the experience, a final group report must be drawn up following the instructions given on Virtuale

In particular, the main points of the work carried out, the data obtained, and the final result(s) accompanied by an adequate statistical analysis must be made explicit in this report. It will also be necessary to highlight which difficulties and problematic aspects have been encountered from a disciplinary, technical, and relational point of view.

Individual discussions. During the last week of the course, individual interviews relating to the laboratory activity will be held. The interviews will be held in the presence of the working group, but the questions will be posed to the individual members of the group itself. The topics under discussion will be closely linked to the activity carried out taking into consideration both the work done in the design phase (for example knowledge of the study materials, reasons for some analysis choices, etc.) and the work and results obtained in the laboratory.

The final laboratory evaluation will take into account both the evaluation given to the group report (30% weighting) and the evaluation of the individual interview (70% weighting).

Please note that the laboratory activity (certified by the final report and individual interview) is mandatory because it is an integral part of the exam and cannot be repeated.

The written exam consists of a first part of true/false and multiple choice questions and a second part consisting of open-ended questions.
The questions involve the resolution of problems and exercises relating to the knowledge acquired and the skills gained on the theoretical, practical and applied contents of the course. The test may also contain questions that focus on prior knowledge and not explicitly covered in the course but which are essential for understanding the contents of the course.

The first part of the test is considered passed if a score equal to or greater than 40% of the maximum obtainable score is achieved. Passing the first part is necessary to access the second part of the test (open-ended questions).

During the written test, the use of textbooks and lesson notes (or slides) is not permitted. 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 weighted average of laboratory evaluation (weight 40%) and of written exam (weight 60%) determine the final grade.

Example: Report grade: 30, individual interview 26, voto scritto 20.

Total laboratory grade: (30x0.3 + 26x0.7) = 27.2

Final exam grade: 27.2x0.40 + 20x0.60 = 10.9 + 12.0 = 23

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.

Part of the planning activities to define the laboratory activities will be conducted using the Teams platform

Office hours

See the website of Sergio Zappoli

See the website of Andreas Stephan Lesch

See the website of Erika Scavetta