The document provides information about analytical chemistry lectures including the lecturer's contact details, lecture times, assessment breakdown, recommended textbooks, class policies, and an overview of topics to be covered in student presentations which include various analytical techniques such as gravimetric analysis, titrimetry, spectroscopy, chromatography, and mass spectrometry.
7. Chemical analysis includes any aspect of the
chemical characterization of a sample
material.
Analytical Chemistry?
◦ “Science of Chemical Measurements”
8. 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?
9. 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)
10. 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.
11. 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…
13. 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
17. Numbers used in analytical chemistry:
Units of measure
Significant figures
Measurable units used in analytical chemistry:
Mass
Volume solute)
(of
Concentration
(of solvent)
(of solution)
18. Units for Expressing Concentration
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
19. Other Concentration Units
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 equivalents
N=nxM
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 = µg/mL
ppb = µg/liter = ng/mL
ppt = ng/liter = pg/mL
20. 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
21. 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
22. Basic/General Principles and Theory
Types/Variation
Description of instruments (if any)
Mechanism of Analysis/Method/Instruments
Examples and Applications
Notas do Editor
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.