Lecture (1) - Analytical.pdf

Dr. Yasmeen AlZahrani Building 1, GF 20 [email protected] YasmeenMoeid Evaluation of Introduction to Analytical Chemistry 1st Semester 2024- 2025 Requirement Week Due Weights Quizzes (1 & 2) 6,12 10% 1 min Report T...

Dr. Yasmeen AlZahrani Building 1, GF 20 [email protected] YasmeenMoeid Evaluation of Introduction to Analytical Chemistry 1st Semester 2024- 2025 Requirement Week Due Weights Quizzes (1 & 2) 6,12 10% 1 min Report Through Semester 5% Midterm exam Official Schedule 15% Final exam Official Schedule 40% Lab Through Semester 30% Total 100%  Analytical Chemistry Books 1) Modern Analytical Chemistry David Harvey DePauw University. 2) Dean's Analytical Chemistry McGraw-Hill Handbooks, 2013- Analytical chemistry for technicians / by John V. Kenkel. CRC press— Fourth Edition 2013. 3) Gary Christian, Analytical Chemistry, 6th Ed. (Wiley)  Lecture (1) Analytical chemistry Chapter 1 ▪ General introduction to analytical chemistry. ▪ Review of Fundamental concepts. ▪ Classification and principles of quantitative methods and chemical analysis. What is Analytical Science? ▪ Analytical Chemistry provides methods and tools needed for giving insight into our material world. ▪ For answering four basic questions about a material sample… o What? o Where? o How much? o What arrangement, structure or form? Conclusion: Chemical analysis includes any aspect of the chemical characterization of a sample material.  Introduction to Chemical Analysis Definition of Analytical Chemistry: ▪ Is a science of chemical measurements or ▪ Is a school of science consisting of a set of powerful methods that are useful, affects in all fields of science and medicine. Analytical chemistry is a science with applications throughout industry, medicine, and all the sciences like: o Physical Chemistry, Organic Chemistry, Inorganic Chemistry: Theory guides but Experiment decides. o Biotechnology: Distinguishing isomers with differing bioactivities & Biosensors. o Materials Science: High-temperature superconductors. o Manufacturing: Quality control of packaged foods specifications. o Forensics: Chemical features for criminal evidence.  Distinction between analytical chemistry and chemical analysis That analytical chemists work to improve established methods. For example, several factors complicate the quantitative analysis of Ni2+ in ores, including: o The presence of a complex heterogeneous mixture of silicates and oxides. o The low concentration of Ni2+ in ores. o The presence of other metals that may interfere in the analysis. ▪ After dissolving a sample of the ore in a mixture of H2SO4 and HNO3, trace metals that interfere with the analysis, such as Pb2+ , Cu2+ and Fe3+ , are removed by precipitation. o Any cobalt and nickel in the sample are reduced to Co and Ni, isolated by filtration and weighed (point A). o After dissolving the mixed solid, Co is isolated and weighed (point B). o The amount of nickel in the ore sample is determined from the difference in the masses at points A and B. 𝑴𝒂𝒔𝒔 𝑷𝒐𝒊𝒏𝒕 𝑨 −𝑴𝒂𝒔𝒔 𝑷𝒐𝒊𝒏𝒕 (𝑩) Ni % = × 100 𝑴𝒂𝒔𝒔 𝑺𝒂𝒎𝒑𝒍𝒆 Examples Of uses: ▪ The concentrations of oxygen and of carbon dioxide are determined in millions of blood samples every day and used to diagnose and treat illnesses. ▪ Smog-control is done by the measurement of quantities of hydrocarbons, nitrogen oxides, and carbon monoxide in automobile exhaust. ▪ Analytical chemistry helps diagnose parathyroid diseases in humans' measurements of ionized calcium in blood serum. ▪ Determination of nitrogen in foods establishes their protein content and thus their nutritional value. ▪ Analysis of steel during its production permits adjustment in the concentrations of such elements as carbon, nickel, and chromium to achieve a desired strength, hardness, corrosion resistance, and ductility. ❑ What do chemical analyst do? ▪ Analyst: o Applies known measurement techniques to well defined compositional or characterization questions. o Research Analytical Chemist. ▪ Senior Analyst: o Develops new measurement methods on existing principles to solve new analysis problems. ▪ Research Analytical Chemist: o Creates and /or investigates novel techniques or principles for chemical measurements. o Conducts fundamental studies of chemical/physical phenomena underlying chemical measurements.  The Analytical Perspective The analytical approach as there are analytical chemists, it is convenient for our purposes to treat it as a five-step process: ◦ 1. Identify and define the problem. ◦ 2. Design the experimental procedure. ◦ 3. Conduct an experiment and gather data. ◦ 4. Analyze the experimental data. ◦ 5. Propose a solution to the problem. ❑ Areas of Chemical Analysis and Questions Qualitative and quantitative methods of analysis ▪ The areas of Qualitative and Quantitation analysis means: How much of substance X is in the sample? ▪ Detection: Does the sample contain substance X? ▪ Identification: What is the identity of the substance in the sample? what is present in a sample? ▪ Separation: How can the species of interest be separated from the sample matrix for better quantitation and identification? ▪ Most qualitative analyses methods used in qualitative applications of identifying organic and inorganic compounds, such as: o Infrared spectroscopy o Nuclear magnetic resonance o Mass spectrometry  Common Analytical Approach for Solving Problems a) Qualitative analysis: o An analysis in which we determine the identity of the constituent species in a sample. b) Quantitative analysis: o An analysis in which we determine how much of a constituent species is present in a sample. c) Characterization analysis: o An analysis in which we evaluate a sample’s chemical or physical properties. o Determinations of chemical structure, equilibrium constants, particle size, and surface structure are examples of a characterization analysis The purpose of a qualitative, quantitative, and characterization analysis is to solve a problem associated with a sample. d) fundamental analysis: o A fundamental analysis, on the other hand, is directed toward improving the experimental methods used in the other areas of analytical chemistry. o Extending and improving the theory on: Which a method is based Studying a method’s limitations Designing new and modifying old methods are examples of fundamental studies in analytical chemistry  Classifying Quantitative Analytical Methods 1. Gravimetric methods: determine the mass of the analyte, or some compound chemically related to it. 2. Volumetric methods: The volume of a solution containing sufficient reagent to react completely with the analyte is measured. 3. Electroanalytical methods: Involve the measurement of such electrical properties as voltage, current, resistance, and quantity of electrical charge. 4. Spectroscopic methods: These are based on measurements of the interaction between electromagnetic radiation and analyte atoms or molecules or on the production of such radiation by analysts. 5. Finally, groups of different methods that include the measurement of such quantities as mass-to-charge ratio of molecules by mass spectrometry, rate of radioactive decay, heat of reaction, rate of reaction, sample thermal conductivity, optical activity, and refractive index. The sample size dictates what measurement techniques can be used.