Analytical Chemistry - Section 1.pdf

University of Mines and Technology Analytical Chemistry (CH & RP 174) Section 1 Dr Benjamin Edem Meteku Department of Chemical & Petrochemical Engineering [email protected] June 2024  Course Objec...

University of Mines and Technology Analytical Chemistry (CH & RP 174) Section 1 Dr Benjamin Edem Meteku Department of Chemical & Petrochemical Engineering [email protected] June 2024  Course Objective The objective of this course is to enable students develop: ❖ An understanding of the fundamentals of analytical chemical concepts ❖And their industrial applications BEM 2  Course Content ❖ Introduction to Analytical Chemistry ❖ Steps in Chemical Analysis ❖ Basic Tools and operation in the analytical Laboratory ❖ Data Evaluation ❖ Volumetric Analysis ❖ Gravimetric Analysis ❖ Spectrophotometric methods of analysis ❖ Chromatography and Electroanalytical Procedures ❖ Modern Instruments and trends in Analytical Chemistry BEM 3  Mode of Delivery ❖ Lectures ❖Tutorials ❖Group Work ❖Assignment. BEM 4  Assessment of Students ❖ Attendance [10%] ❖ Continuous Assessment [30%] - Assignments - Quizzes ❖ End of Semester Exams [60%] BEM 5  Reading Materials i. Skoog, D.A., West, D.M., Holler, F.J. and Crouch, S.R. (2013), Fundamentals of analytical chemistry, Cengage learning, Massachusetts, United States, 9th Edition, 1001 pp. ii. Cases, M. V., López-Lorente, Á. I. and López-Jiménez, M. Á. (2018), Foundations of Analytical Chemistry, Springer International Publishing, Cham, 487 pp. iii.Gary, D. C., Dasgupta, K. P. and Schug, K. A. (2013), Analytical Chemistry, Wiley, New York, United States, 7th Edition, 848 pp. BEM 6  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ What is Analytical Chemistry? ❖Analytical chemistry is the branch of chemistry that deals with the separation, identification and determination of components in a sample. It also includes the statistical treatment of data. BEM 7  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Main Objective of Analytical Chemistry BEM 8  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Objectives of Analytical Chemistry BEM 9 INTRODUCTION TO ANALYTICAL CHEMISTRY BEM 10  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Applications of Analytical Chemistry ❖ Medicine: Analytical Chemistry is the basis for clinical laboratory test which helps physicians to diagnose diseases and chart progress in recovery. ❖ Industry: Analytical Chemistry provides the means of testing raw materials, assuring the quality of products whose composition is critical ( pharmaceuticals, household products, fuel, paints etc) BEM 11  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Applications of Analytical Chemistry ❖ Environmental Quality: Often evaluated by testing for/ monitoring suspected contaminants ❖ Nutritional Value of Food: Major components of food such as protein, carbohydrates, trace amounts of vitamins and minerals. Even calories in food are often calculated from chemical analysis. BEM 12  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Applications of Analytical Chemistry ❖ Forensic Analysis: Analysis related to criminology such as DNA finger printing, blood analysis etc. ❖ Pharmaceutical Sciences: For quality control purposes in the pharmaceutical industry, analytical toxicology( concerned with detection, identification and measurement of drugs and other foreign compounds in biological species) BEM 13  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Applications of Analytical Chemistry ❖ Safety and Quality of Food: For assuring the safety and quality of food and water via the measurement of critical parameters ❖ Research and Regulatory Compliance: For research into new frontiers to confirm or corroborate findings. Setting standards for legal compliance BEM 14  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ NB In the field of Chemical and Petrochemical Engineering, analytical chemistry is usually deployed as quality engineering. BEM 15  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ Codex Alimentarius: Also known as the “food code” is a collection of standards, guidelines and codes of practice adopted by FAO and WHO to ensure food safety and quality and promote fair practices in food trade. Examples include - Nutrition and labelling eg expiry dates - Biotechnology eg GMO’s etc BEM 16  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ Good Manufacturing Practices (GMP’s): GMP is a system for ensuring that products are consistently produced and controlled according to quality standards. It is mainly employed in the pharmaceutical and food industries. The five elements or pillars of GMP (5 P’s of GMP) are: - People (should be well trained) - Procedures (work instruction for an activity) – SOP’s - Products (constant testing and comparison) – master formula - Premises (clean and hygienic) - Processes (well documented) – problems with a batch traceable BEM 17  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ ISO Standards: These are a set of internationally recognized standards that were created to promote levels of homogeneity in the provision of services and development of products. ISO 9001:2015 ISO 14001:2015 ISO 22000:2018 and HACCP ISO 45001:2018 ISO 17025:2017 (Management System for Labs) BEM 18  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ Warehousing/Material Storage The basic function of the warehouse in the production chain is to ensure raw materials are available for production or finished products are available for the market. Rules - FEFO - FIFO Necessary Documents - COA - MSDS BEM 19  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ ASTM Methods American Society for Testing and Materials is a standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials and products 1898 – Charles Benjamin Dudley ( American Society for Testing Materials) 1961–American Society for Testing and Materials 2001 – ASTM International ( currently, over 13000 standards) BEM 20  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ ASTM Methods Example ASTM standard test for crude oil quality parameters is D--- Eg Cloud point of crude oil – ASTM D2500 Pour point of crude oil – ASTM D97 Sulphur content of crude oil – ASTM D4294 Total Acid Number (TAN) of crude oil – ASTM D664 API Gravity by hydrometer – ASTM D287 BEM 21  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer ❖ Root Cause Analysis Tools In industrial production, problems are bound to occur……. RCA is the process of identifying the root cause of problems in order to identify appropriate solutions. 1. Pareto Analysis: 80% of problems or challenges are traced back to 20% of causes. 2. FMEA: Failure Modes and Effect Analysis proactively anticipates possible failure modes of equipment 3. Ishikawa diagram: visually shows how causes and effect BEM 22  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Introductory Concepts for the Quality Engineer Ishikawa diagram: BEM 23  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ ASSIGNMENT Question: 1. Identify a resource in your Hometown 2. State the District and the Region 3. State any two uses of the resource or final products of the resource 4.List any 2 quality parameters of the resource or product and state any standard test method that can be used for the analysis. BEM 24  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Basic Definitions and Terminologies ▪ Sample: Is anything that comes to mind in the air, water, soil, food and living organisms such as a piece of rock, a piece of meat, some water from a tank or river or sea, some tissue or blood from human etc. The sample is usually taken to the laboratory and analyzed ▪ Analyte: Is a constituent of a sample that is analyzed for and its concentration determined (constituent of interest) BEM 25  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Basic Definitions and Terminologies ▪ Analysis: Is a process that provides chemical or physical information about the constituents in the sample or the sample itself. ▪ Matrix: All other constituents in a sample except for the Analyte. ▪ Determination: An analysis of a sample to find the identity, concentration, or properties of the Analyte ▪ Measurement: An experimental determination of an analyte’s chemical or physical properties BEM 26  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Basic Definitions and Terminologies ▪ Technique: A chemical or physical principle that can be used to analyze a sample ▪ Method: A means for analyzing a sample for a specific analyte in a specific matrix. ▪ Procedure: Written directions outlining how to analyze a sample. ▪ Protocol: A set of written guidelines for analyzing a sample provided by an agency BEM 27  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Basic Definitions and Terminologies ▪ Precision: Describes the reproducibility of a result ▪ Accuracy: Describes how close a measured value is to the true value High Precision High Precision Low Precision Low Precision High Accuracy Low Accuracy High Accuracy Low Accuracy BEM 28  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative and Quantitative Analysis BEM 29  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Types of Analysis (Qualitative and Quantitative) The two general areas of analytical chemical analysis, Qualitative and Quantitative analysis may be either; Classical Or Instrumental BEM 30  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative Analysis ▪ It involves the identification of elements, ion and compounds present in a sample. ▪ The sample may be solid, liquid or gas Example: In a forensic analysis, the presence of a gunpowder residue on the hand generally requires only qualitative analysis. ( why???) BEM 31  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative Analysis ▪ A qualitative test may be performed by selective chemical reactions or with the use of instrumentation. ▪ Selective and Specific Reactions: - Selective Reactions can occur with other substances but exhibits a degree of preference to the substance of interest. - Specific Reactions are reactions that occur with only the substance of interest. NB: Only few reactions are specific but many are selective BEM 32  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative Analysis - Classical ▪ This analysis detects (identify) the type of all or some of the substances present in the sample (elements or ions or compounds) using simple tools or basic equipment ▪In other words it gives an answer to the question: What substances are present in a sample? ▪ Many reagents that give distinctive colors with some of the substances and can be used in the detection of these substances. The flame also can be used for the detection of some common metals BEM 33  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative Analysis - Classical For example, when you add silver nitrate solution to the sample solution a white precipitate formation indicates the presence of chloride ion in the sample. BEM 34  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Qualitative Analysis - Instrumental There are many instruments that separate and distinguish substances in a sample such as Gas Chromatography – Mass Spectrometry (GC- MS), High Performance Liquid Chromatography – Mass Spectrometry (HPLC- MS), Infra-red spectra (IR), Induced Coupled Plasma – Mass Spectrometry (ICP –MS), etc BEM 35  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Quantitative Analysis ▪ Determination of how much (amount/quantity) of one or more constituents is present Example: The price of diesel will be determined by the percent of Sulphur impurity present ▪ A large portion of this course will deal with quantitative methods (how much of a material is present) BEM 36  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Quantitative Analysis ▪ Depending on the concentration of the desired substance in the sample, classical or instrumental analysis may be used. BEM 37  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Quantitative Analysis - Classical Depends on chemical reactions such as volumetric and gravimetric analysis. It involves the use of simple equipment such as burettes, balances, flame, furnace. It is used to estimate high concentrations ( more than 0.001M) BEM 38  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Quantitative Analysis - Instrumental This type of analysis uses instruments and depends on the physico-chemical properties of the analyte such as absorption or emission of electromagnetic radiation (spectroscopic methods of analysis) or electrical properties. BEM 39  INTRODUCTION TO ANALYTICAL CHEMISTRY ❖ Quantitative Analysis - Instrumental All these methods are used to estimate low concentrations of the analyte (less than 0.001 M), but most of the instrumental analysis methods require expensive instruments. BEM 40  STEPS IN CHEMICAL ANALYSIS ❖ Analytical Methodology (Steps in Chemical Analysis) 1. Plan: This involves identifying and defining the problem, the information required, or available and which technique is suitable or available for use. 2. Sampling: A chemical analysis is often performed on a small portion of material. This portion must have some characteristics of the whole sample. BEM 41  STEPS IN CHEMICAL ANALYSIS 3. Sample Preparation: Depends on the analytic technique to be used. Sample preparation steps may include crushing, drying, dissolution etc. Most analytical methods require liquid forms of sample hence samples are dissolved quantitatively and diluted to the required concentration. BEM 42  STEPS IN CHEMICAL ANALYSIS 4. Eliminating Interferences: The sample to be analyzed may contain solutes which interfere with the determination of the analyte. The sample should be separated from the sample matrix to avoid interference. BEM 43  STEPS IN CHEMICAL ANALYSIS Analytical Methodology 5. Analytical Measurement: This implies conducting the specific analytical procedure and collecting the required data 6. Data Analysis: The obtained data is analyzed to check whether it makes sense or not and reported. BEM 44  STEPS IN CHEMICAL ANALYSIS ❖ 1. Planning / Technique to be used The planning stage is the first step and involves deciding on the technique to employ for analysis. Factors that determine the choice of a specific analytic procedure include: - Cost: Inexpensive methods of analysis include volumetric and gravimetric methods of analysis. Instrumental methods are relatively expensive - Availability of Equipment and Materials: Equipment and materials should be available in the lab for the chosen method. BEM 45  STEPS IN CHEMICAL ANALYSIS ❖ 1. Planning / Technique to be used - Accuracy and Precision : Accurate and precise methods of analysis are needed though are expensive. Example: In estimating salt content of sea water, there is no need for an expensive method. However, in estimating mercury level in sea water, an accurate and precise method (though expensive) is needed – why??? BEM 46  STEPS IN CHEMICAL ANALYSIS ❖ 1. Planning / Technique to be used - Sensitivity: The selected method must be able to determine the analyte in the sample. For example, if the concentration of the analyte in the sample is 0.00001 M, sensitivity of the method (instrument) should be less than 0.00001 M - Type of Interferences: Choosing methods with least or minimal interferences. Impurities are potential interferences and must be removed from the substance to be analyzed in the sample. BEM 47  STEPS IN CHEMICAL ANALYSIS ❖ 1. Planning / Technique to be used - Speed: If the analysis requires the results as soon as possible, we must choose a fast method even if it is at the expense of accuracy and precision. - The number of samples to be analyzed: If the number of samples to be analyzed is high we must choose an automatic and fast method of analysis. Check approved journals in analytical chemistry. BEM 48  STEPS IN CHEMICAL ANALYSIS ❖ 1. Planning / Technique to be used Furthermore, at the planning stage, we must know what type of information is needed eg - Complete Analysis: Determine amount of each component in sample - Ultimate Analysis: Amount of each element present without regard to actual composition - Partial Analysis: Determine one species or limited components in sample. Eg Au in an ore sample. BEM 49  STEPS IN CHEMICAL ANALYSIS ❖ 2. Sampling - Must be representative To ensure results reflect the true average composition. Example: Sampling crude palm oil, water, etc - Sample selection Requires some knowledge as to sample source and history. Random sampling may help. Powder the sample, blend the sample etc. BEM 50  STEPS IN CHEMICAL ANALYSIS ❖ 3. Sampling Preparation - The sample must be converted into a form suitable for the method of analysis. The preparation steps may include - Drying to ensure accurate weight - Sample Dissolution - Conversion of analyte into a single or measureable form usually the liquid form. BEM 51  STEPS IN CHEMICAL ANALYSIS ❖ 4. Eliminating Interferences - A reagent that reacts with a chemical species which is capable of interfering with a chemical analysis is known as masking agent. Masking agents remove impurities (interfering species) from a chemical reaction. Example: EDTA serves as masking agent in spectrophotometric determination of copper. BEM 52  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement - Measure the concentration of analyte in several aliquots. The purpose of replicate measurements(repeated measurement) is to assess the variability (uncertainty) in the analysis and to guard against a gross error in the analysis of a single aliquot. - If necessary, use different analytical methods on similar samples to make sure that each method gives the same result and that the choice of analytical method is not biasing the result. BEM 53  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement - BEM 54  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement BEM 55  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement BEM 56  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement BEM 57  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement Electrochemical BEM 58  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement Spectral Method BEM 59  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement Chromatography BEM 60  STEPS IN CHEMICAL ANALYSIS ❖ 5. Analytical Measurement BEM 61  STEPS IN CHEMICAL ANALYSIS ❖ 6. Data Analysis / Results BEM 62  ACKNOWLEDGEMENT Materials for the lecture presentations were adapted from the works of the following; 1. Rev Dr Johannes Ami 2. Dr Cornelius B. Bavoh 3. Dr Gideon Abaidoo Ocran BEM 63