66295 - Chemometrics

Course Unit Page

  • Teacher Dora Melucci

  • Credits 6

  • SSD CHIM/01

  • Teaching Mode Traditional lectures

  • Language Italian

  • Campus of Bologna

  • Degree Programme Second cycle degree programme (LM) in Chemistry (cod. 9072)

  • Teaching resources on Virtuale

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Quality education Industry, innovation and infrastructure

Academic Year 2021/2022

Learning outcomes

Students learn basics about theory and practice of Chemometrics for Analytical Chemistry.

At the end of the course, students have the following expertise: design of experiments; data processing by multivariate analysis; use of modern software for the application of mathematical and statistical methods.

Students will be able to apply the new skills to real problems concerning applications and research.

Course contents

Prerequisites

Students attending this course must have a good education in the fundamentals of analytical chemistry and instrumental analytical techniques.

Target

The course aims to provide students with the ability to design a chemical-analytical methodology from sampling to data analysis, starting from the design of experiments to arrive at the correct processing of data and presentation of the final technical report.

With these objectives, the following mathematical and statistical knowledge are provided:

Elements of multivariate statistical analysis
Methods of exploration of multivariate data
Multivariate modeling methods: multivariate classification and regression
Design of experiments (DOE)

The student will acquire the computer skills for the application of chemometric methods learned.

Finally, the student will develop the specific competence of a Chemometrician: optimize an entire chemical analysis process.

Contents

UNIVARIATE STATISTICAL ANALYSIS

Confidence interval. Significant figures. Significance test: t-test, F-test, Q-test, Chi-square test.

ANOVA for comparing various confidence intervals.

Calibration by means of a calibration line. Verification of the model by ANOVA. Method of standard additions, matrix effect, limit of detection. Internal standard method.

Error propagation. Paired t-test. Comparison of methods. Control cards. Non-parametric methods.

MULTIVARIATE DATA EXPLORATION

Multivariate structure of data. Matrices: dimension, transposition, centering, covariance, correlation. Pretreatment of the data. Transformation of variables. Handling of missing data.

Principal component analysis. Loading plots. Score plots. Choice of principal components (rank analysis), both numerically and graphically (scree plot).

Clusters analysis. Distance matrix, similarity matrix. Agglomerative hierarchical methods for the analysis of clusters. Dendrograms.

MULTIVARIATE MODELING

Models. Order and linearity of a model. Control parameters. Validation of a model.

Classification: qualitative models. Confusion matrix. Loss matrix. Control parameters. Misclassification risk (MR%). Classification by K-NN. Discriminant analysis (DA). Classification by SIMCA. Classification by CART.

Calibration: quantitative models. Linear regression: MLR method. Leverages. Regression coefficients. Evaluation parameters for a regression model. Correlation coefficient. Prediction coefficient. Standard error of the estimate. Diagnostic methods for regression models. Principal Component Regression (PCR). Partial Least Squares Method (PLS). Practical examples of calibration by means of PLS regression: spectrophotometry, pulsed stripping voltammetry, chromatography-mass spectrometry.

DESIGN OF EXPERIMENTS

Multivariate methods for the selection of standard samples and variables for model creation. Full Factorial Design. Fractional Factorial Design. Mixtures Design.

Readings/Bibliography

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

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

- Richard Kramer, Chemometric techniques for quantitative analysis, Marcel Dekker, 1998

- Ron Wehrens, Chemometrics with R, Spinger, 2011

Teaching methods

The course consists of lectures (32 hours) and exercises in the computer lab (24 hours).

Lectures are dedicated to the acquisition of the basic concepts of Chemometrics and to the acquisition of specific informatic tools (software for mathematics and statistics).

Exercises in the computer lab are designed to enable students to use Chemometrics tools and to apply concepts and software to solve real problems of multivariate chemical analysis.
In consideration of the type of activity and the teaching methods adopted, the attendance of this training activity requires the preventive participation of all students in modules 1 and 2 of training on safety in the study places, [https: //elearning-sicurezza.unibo .it /] in e-learning mode.

Crucial will be the use of material provided by the lecturer made available online [https://virtuale.unibo.it/] and lecture notes.

Assessment methods

At the end of the course, students must deliver a report about a chemometric problem, relevant to a dataset provided by the teacher. Problems are individual: each student works on a different dataset. The chemometric data-processing in the final report is similar to what explained during the course, in guided exercises relevant to model-datasets. The report must be in the form of a text document. It is NOT required to deliver file corresponding to the numerical calculations, while it is required that numerical or graphical outputs be included . The teacher assigns a mark to the final report.
The examination consists of oral questions about the final report and the theory explained in the room lessons (definitions and demonstrations). The teacher assigns a mark to the oral examination.
The final mark is the average of the mark assigned to the report and the mark assigned to the oral exam.

Teaching tools

Blackboard for theoretical lessons. Video projector for explanation of spreadsheets. Informatic laboratory for exercises.
For lectures and exercises the teacher uses the following programs: Microsoft Excel and "R". The software "R" is used in the simplified version CAT, which can be dowloaded from the site http://gruppochemiometria.it/index.php/software.


To carry out individual exercises and calculations for the final report, students can use the PCs of the informatic laboratory or they can use their computers, both in presence and in remote mode.

Office hours

See the website of Dora Melucci