chapter 1 introduction to analytical chemistry
TRANSCRIPT
Lecturer: Dr Sumaiya Zainal AbidinRoom: A3-08
Email: [email protected]
◦4.00 PM – 5.00 PM (Tuesday)
◦10.00 AM – 11.00 AM (Wednesday)
Lectures
4.00 PM – 6.00 PM (Thursday; W-DK-01; 2 hours)
4.00 PM – 5.00 PM (Friday; W-DK-01;1 hour)
Method of Assessment % Distribution
Test 1 20%
Test 2 20%
Presentation 6%
Quizzes 7%
Assignments 7%
Final Examination 40%
Total 100%
David Harvey – Modern Analytical Chemistry (McGraw Hill)
Kealy & Haines – Analytical Chemistry Skoog et al. – Fundamental of Analytical
Chemistry
CLASS POLICY100% attendance
PunctualityAsk questions
Chemical analysis includes any aspect of the chemical characterization of a sample material.
Analytical Chemistry?◦“Science of Chemical Measurements”
Quantitation:◦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? Separation:
◦How can the species of interest be separated from the sample matrix for better quantitation and identification?
Analytical Chemistry provides the methods and tools needed for insight into our material world…for answering four basic questions about a material sample?
What? Where? How much? What arrangement, structure or form?(Fresenius’ J. Anal. Chem. 343 (1992):812-
813)
Analytical chemists work to improve the reliability of existing techniques to meet the demands of for better chemical measurements which arise constantly in our society.
They adapt proven methodologies to new kinds of materials or to answer new questions about their composition.
They carry out research to discover completely new principles of measurements and are at the forefront of the utilization of major discoveries such as lasers and microchip devices for practical purposes.
Classical methods: early years (separation of analytes) via precipitation, extraction or distillation
Qualitative: recognized by color, boiling point, solubility, taste
Quantitative: gravimetric or titrimetric measurements
Instrumental Methods: newer, faster, more efficient
Physical properties of analytes: conductivity, electrode potential, light emission absorption, mass to charge ratio and fluorescence, many more…
©Gary Christian, Analytical Chemistry, 6th Ed. (Wiley)
Qualitative analysis is what.
Quantitative analysis is how much.
Qualitative analysis is what.
Quantitative analysis is how much.
Gravimetric Methods determine the mass of the analyte or some compound chemically related to it.
Volumetric Methods measure the volume of a solution containing sufficient reagent to react completely with the analyte
Electroanalytical Methods involve the measurement of electrical properties such as voltage, current, resistance, and quantity of electrical charge
Spectroscopic Methods are based on the measurement of the interaction between electromagnetic radiation and analyte atoms or molecules, or the production of such radiation by analytes
Miscellaneous Methods include the measurement of such quantities as mass-to-charge ratio, rate of radioactive decay, heat of reaction, rate of reaction, sample thermal conductivity, optical activity, and refractive index
Fig. 1.1. Steps in an analysis
An analysis involves several steps and operations which depend on:
•the particular problem
• your expertise
• the apparatus or equipment available.
The analyst should be involved in every step.
An analysis involves several steps and operations which depend on:
•the particular problem
• your expertise
• the apparatus or equipment available.
The analyst should be involved in every step.
©Gary Christian, Analytical Chemistry, 6th Ed. (Wiley)
Different methods provide a range of precision, sensitivity, selectivity, and speed capabilities.
Different methods provide a range of precision, sensitivity, selectivity, and speed capabilities.
©Gary Christian, Analytical Chemistry, 6th Ed. (Wiley)
Numbers used in analytical chemistry: Units of measure Significant figures
Measurable units used in analytical chemistry:
Mass Volume Concentration
(of solute)(of solvent)
(of solution)
Concentration is a general measurement unit starting the amount of solute present in a known amount of solution/solvent
Concentration= amount of solute amount of solution
= amount of solute amount of solvent
Units for Expressing Concentration
Molarity, M – Is the concentration of a particular chemical species in solution
Formality – is a substance’s total concentration in solution without regard to its specific chemical form
Normality, N – the amount of one chemical species reacting stoichiometrically with another chemical species
EW = FW / n , n = number of equivalentsN = n x M
Molality – used in thermodynamic calculation where a temperature independent unit of concentration is needed
Weight, volume and weight to volume ratios - %w/w, %v/v and %w/v express concentration as units of solute per 100units of sample
Parts per million, billion and trillion are the minute concentration units which also use the compatible metric units as follows:
ppm = mg/liter = g/mLppb = g/liter = ng/mLppt = ng/liter = pg/mL
Other Concentration Units
Name Units Symbol
Molarity Moles solute/liters solution M
Formality No.FWs solute/liters solution F
Normality No.EWs solute/liters solution N
Molality Moles solute/kg solvent m
Weight % g solute/100g solution %w/w
Volume % mL solute/100mL solution %v/v
w/v % g solute/100 mL solution %w/v
ppm g solute/106 solution ppm
ppb g solute/109 g solution ppb
ppt g solute/1012 g solution ppt
Other Concentration Units
List of Presentation Topics
◦ Gravimetric Analysis◦ Titrimetric Analysis◦ UV-Vis◦ Infra-Red◦ Atomic Absorption Spectrometry◦ Flame atomic Emission Spectroscopy◦ Inductively Coupled Plasma Spectrometry◦ Gas Chromatography◦ Gas Chromatography Mass Spectrometry ◦ Liquid Chromatography◦ Liquid Chromatography Mass Spectrometry
Basic/General Principles and Theory Types/Variation Description of instruments (if any) Mechanism of Analysis/Method/Instruments Examples and Applications