Chemistry
502 - Instrumental Methods of Analysis – Spring 2003
Qualitative
and quantitative methods of chemical analysis for organic, biochemical, and
inorganic compounds fall into two categories, classical (or wet) methods
and instrumental methods. Chemistry 313 surveyed many classical methods
and some instrumental methods of analysis. Although there is not always a clear
barrier between the two, the primary difference arises from the type of
physical property used to provide information. Classical methods often rely on
reactivity or physical properties such as solubility, melting and boiling
points, odors, or refractive indices for qualitative information, while
gravimetric, volumetric, and titrimetric measurements provide quantitative
information. Classical methods for the
separation of mixtures are mainly solvent extractions or distillations.
Instrumental methods typically utilize other physical properties such as
absorption or emission of light, mass-to-charge ratio, or electrode
potential. Separations are carried out
by more efficient chromatographic methods.
Instrumental
methods certainly extend well beyond the chemistry lab. These instruments are
found in biotechnology, environmental, geological, materials, forensic,
medical, nutritional, and industrial labs. Unfortunately, some scientists view
and utilize these instruments as "black boxes". This term implies a
device in which the scientist places a sample and somehow a number is generated
that influences the scientist’s decision-making process. It should be apparent
that this approach could be dangerous, as the old saying "Garbage In/Garbage
Out" is often true. As such any scientist using such sophisticated
equipment needs at least a basic understanding of how these instruments work.
Instrumental
Methods of Analysis is a broad subject, but the methods are generally
categorized as either spectroscopic, electrochemical, or chromatographic. We will essentially take the cover off the
"black box" and see how these instruments are constructed and
measurements made from the underlying chemical and physical properties of the
substance. Quantitative problem solving
will be utilized as a means to demonstrate physical principles applied in the
design and performance of instruments.
The
goal of this course is not to make you an "expert" on each type of
instrumentation encountered, but rather to introduce and educate you to the
many types of instruments available for chemical analysis and the type(s) of
information these instruments provide. It is my hope that you will then expand
your knowledge of the instruments you come into contact with during your
scientific career, thereby avoiding the "black box" problem.
Specific
Course Objectives:
By
the end of this course, you should:
- Have an
understanding of how chemical and physical properties of substances are
used in the design and construction of sophisticated instrumentation used
in chemical analysis
- Have a broad
knowledge of the types of instrumentation generally available and the
information provided by each
- Understand the
advantages, disadvantages, and limitations of different instruments used for
similar types of analyses
- Use rigorous
mathematical methods for evaluating instrument performance
Time/Location:
11:00 - 12:15 TR / Sims 301-B
Professor:
Dr. C. Calloway callowayc@winthrop.edu
Office:
312-B Sims Hall; 323-4945
Office
Hours: TRF 8:00 - 10:00
a.m. {and other times by appointment.}
Textbook:
Principles of Instrumental Analysis, 5thedition,Skoog,
D.A., Holler, F.J., Nieman, T.A.
You
may find the website, "Chemistry Hypermedia
Project" (Analytical Chemistry Tutorial), a useful tool.
Grading/Evaluation:
Note: Since all graded work (including homework to
be collected, quizzes, papers, mid-term examinations, final examination, research
proposals, laboratory results and reports, etc.) may be used in the
determination of academic progress, no collaboration on this work is permitted
in this course unless the instructor explicitly indicates that some specific
degree of collaboration is allowed. This statement is not intended to
discourage students from studying together, seeking help from the instructor,
or working together on assignments that are not to be collected.
Grades in this course will be determined from three
sources, as follows:
- Homework (20%):
Periodically, homework problems will be assigned, from the textbook or as
handouts, and collected. Of those assigned, a random number, or all, will
be graded and returned. Due dates
given for each assignment are the final date each assignment will be
accepted.
- Mid-term Exams
(60%): There will be 4 exams given during the term covering the topics
listed below. Make sure to bring a pencil and calculator to the exam. No
make-up exams will be given. If an
exam is missed with a valid excuse, as determined by the instructor, the
final exam will count as the missed exam grade. The exams are scheduled as follows:
- Exam
1: February 4
- Exam
2: March 4
- Exam
3: April 8
- Exam
4: April 24
- Final Examination:
20% {Thursday, May 1/11:30 a.m.} There will be a cumulative final
examination given during exam week. If you score higher on the final exam
than your lowest mid-term exam, the final exam grade will replace the
lowest exam grade, before averaging.
Letter
grades will be assigned as follows:
90 - 100%: A
80-89%: B
70-79%: C
60-69%: D
Menu
of Topics:
- Analytical Figures
of Merit, Basic Electronics, Signal-to-Noise Theory (Ch. 1,2,and 5)
Exam 1
- Spectroscopic
Instrument Design & Atomic Spectroscopy - (Ch. 6 – 10)
Exam 2
- Molecular
Electronic and Vibrational Spectroscopy (Ch. 13-18)
- Nuclear Magnetic
Resonance Spectroscopy- (Ch. 13-19)
Exam 3
- Atomic and
Molecular Mass Spectrometry (Ch. 11,20)
- Surface Analysis
(Ch. 21)
- Electro-analytical
Chemistry (Ch. 22-25)
Exam 4
Students
with Disabilities: If
you have a disability and need classroom accommodations, please contact
Services for Students with Disabilities, at 323-2233, as soon as possible. Once you have your “professor notification
letter”, please notify me so that I am aware of your accommodations well before
the first test.
My
advice, to help you succeed in this endeavor:
- Read your
textbook.
- Be sure you
know how to do mean, standard deviation, and linear regression on your
calculator.
- Stay ahead
of the lectures in your reading.
- Work the
homework problems by yourself, without any aid.
- Don’t fall
behind.
- Wear
sunscreen.
- Read your
textbook.
- Floss at
least once a day.
- Talk to your
professor, especially if you are confused.
- Get a good
night’s rest.
- Read your
textbook.
- Sing
occasionally.
- Above all,
read your textbook.
We, the members of the
Winthrop University Community, pledge to hold ourselves
and peers to the highest standards of honesty and integrity
Instrumental Analysis
Student Competencies
Principles of Instrumental Analysis, 5th. Ed.,
Douglas A. Skoog, F. James Holler, Timothy A. Nieman, 1998.
Chapter 1 Student competencies
Upon completion of this chapter, students should
be able to:
- Differentiate
between Classical Methods of Analysis and Instrumental Methods of
Analysis.
- Describe the
different domains through which data is passed within a sophisticated
instrument.
- Understand
the terms detector, transducer, and sensor.
- Have a
general knowledge of how to select an analytical method for chemical
analysis.
- Calculate
and interpret analytical figures of merit, including accuracy, precision,
signal-to-noise ratio, sensitivity (calibration and analytical), limit of
detection (LOD), linearity via log-log plots, and linear dynamic range
(LDR)
- Utilize
calibration, standard addition, and internal standard methods of analysis,
as introduced in Quantitative Analysis.
Chapter 2 Student competencies
Upon completion of this chapter, students should
be able to:
- Utilize
the basic laws of electricity, including Ohm’s Law, Kirchoff’s current and
voltage laws, and the power law to find voltage, current, resistance or
wattage.
- Determine
the total resistance in a series circuit or calculate voltage at various
points in a voltage divider.
- Determine
the total resistance in a parallel circuit or calculate the current at
various points in a current divider.
- Differentiate
between dc and ac circuits.
- Work
with expressions for sinusoidal currents, including terms related to
amplitude, period, frequency, angular velocity, and phase angle.
Chapter 5 Student competencies
Upon completion of this chapter, students should
be able to:
- Determine
and interpret the meaning of the signal-to-noise ratio.
- Explain
sources of instrumental noise, including shot, flicker, and environmental
noise, and factors that influence the magnitude of each.
- Classify
an instrument as shot or flicker noise limited.
- Understand
the various hardware techniques used to reduce environmental and external
electronic noise sources.
- Describe
the purpose of differential and instrumental amplifiers in instrumental
design as well as contrast the advantages and disadvantages of each type
of amplifier
- Describe
the purpose of high pass; low pass; and narrow band pass analog filters in
instrument design.
- Discuss
the technique of modulation/demodulation in noise reduction of dc signals.
- Describe
how a lock-in amplifier works.
- Understand
the various software techniques used to reduce noise including ensemble
averaging, boxcar averaging, digital filtering, and Fourier transform.
Chapter
6 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the wave and particle properties of electromagnetic radiation.
- Inter-convert
between wavelength, frequency, period, energy, and wavenumber.
- Describe
the relative ordering of the electromagnetic spectral regions and the
types of transitions that occur in each region.
- Describe
the superposition of wave theory, and how this relates to Fourier
transform
- Describe
diffraction of radiation.
- Define
coherent radiation, blackbody radiation, fluorescence, phosphorescence,
resonance fluorescence, Stokes and Anti-Stokes Shifts.
- Contrast
line, band, and continuum spectra.
- Inter-convert
between transmittance and absorbance data.
- Utilize
Beer’s Law to determine concentrations from absorbance data, and vice
versa.
Chapter
7 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
and diagram the basic components in absorption, emission, and luminescence
optical spectrometers
- List
and describe some common light sources used in the infrared, visible, and
UV regions of the electromagnetic spectrum
- Describe
the differences between line, continuum, and quasi-continuum light
sources, and the applications of each.
- Describe
the components of a laser.
- Describe
the four mechanisms involved in a laser and which processes contribute to
or attenuate laser power.
- Describe
various wavelength selectors including absorption filters, interference
filters, and monochromators (Bunsen, Czerny-Turner, and Echelle.
- Describe
how diffraction gratings disperse light.
- Utilize
the grating formula to calculate wavelengths at various incident and
reflected angles for various orders.
- Understand
the terms single channel and multi channel radiation transducer.
- List
and describe phototubes, photomultiplier tubes, and silicon photodiodes.
- List
and describe linear diode arrays, charge coupled devices, and charge
injection devices.
Chapter
8 Student competencies
Upon completion of this chapter, students should
be able to:
- Understand
data found in atomic energy level diagrams
- Describe
natural, Doppler, and pressure line broadening effects in atomic
spectrometry
- Utilize
the Boltzman equation to determine relative populations of atomic energy
levels at various temperatures.
- Describe
common atomizers used in atomic spectroscopy including flames,
electrothermal vaporization, inductively coupled plasma (ICP), direct
current plasma (DCP), microwave induced plasma (MIP), glow discharge, arcs
and sparks, differentiating between continuous and non-continuous operation.
- Describe
common sample introduction methods in atomic spectrometry including
pneumatic and ultrasonic nebulization, electrothermal vaporization,
hydride and cold vapor generators, direct insertion, laser ablation, arc
and spark ablation, and glow discharge sputtering.
Chapter
9 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the process occurring during atomization.
- Describe
common atomizers used in atomic absorption and fluorescence spectrometry
including flames, electrothermal atomizers, glow discharge, cold vapor,
and hydride generation.
- Describe
the structure of a flame, the various fuels and oxidants used, and
absorption observed in a flame.
- Describe
the components of an electrothermal atomizer, including the purpose of the
L’vov platform.
- Describe
the stages of operation in an electrothermal atomizer.
- Compare
performance characteristics of a flame and electrothermal atomizer
- Describe
the purpose and method of using hydride generators and cold vapor atomization
techniques.
- Describe
hollow cathode lamp sources and electrodeless discharge lamps
- Explain
the purpose of source modulation in AAS
- Discuss
spectral interferences in AAS and correction methods including the
two-line, deuterium, Zeeman, and Smith-Hieftje methods.
- Discuss
chemical interferences including ionization and oxide formation, as well
as methods used to reduce these problems.
- Describe
the instrumentation commonly used for atomic fluorescence spectrometry.
Chapter
10 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the construction and operational characteristics of an inductively coupled
plasma (ICP)
- Describe
sample introduction techniques used in ICP.
- Describe
the construction and operational characteristics of a dc plasma (DCP)
- Compare
the advantages and disadvantages of ICP vs. DCP and sparks/arcs.
- Explain
why ICP can be employed as a simultaneous elemental analysis technique.
- Discuss
the use of internal standards in atomic emission spectrometry.
Chapter
13 Student competencies
Upon completion of this chapter, students should
be able to:
- Differentiate
between radiant power and intensity.
- Define
and calculate transmittance and absorbance.
- Differentiate
between absorptivity and molar absorptivity in Beer’s Law
- Derive
Beer’s Law.
- Give
limitations to Beer’s Law
- Utilize
Beer’s Law in solving for concentration of mixtures and equilibrium
concentrations.
- Describe
what is meant by photometric error.
- Describe
the components and arrangements of a single beam and double beam
spectrophotometer and the purpose of each design.
- Describe
common sources and detection systems used in molecular UV/Vis
spectrometry.
Chapter
14 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the types of transitions commonly observed in UV/Vis spectrometry,
including ÔàÔ*,
nà
Ô*,
nà
Ñ*,
and Ñ à
Ñ*
- Predict
the types of transitions available for molecules, approximate wavelength
ranges, and expected molar absorptivities.
- Define
the term chromophore, and list common organic compound chromophores.
- Apply
common methods of chemical analysis, including calibration curve and
standard addition to UV/Vis absorption data.
Chapter
15 Student competencies
Upon completion of this chapter, students should
be able to:
- Explain
the terms resonance fluorescence, Stokes shift, diamagnetic, paramagnetic,
singlet state, doublet state, and triplet state.
- Draw
energy level diagrams representing fluorescence and phosphorescence
indicating absorption, internal conversion, vibrational relaxation,
intersystem crossing, fluorescence, and phosphorescence.
- Distinguish
between fluorescence and phosphorescence.
- Define
quantum yield.
- Discuss
variables that affect fluorescent and phosphorescent quantum yield including
structure relationships, type of transition, dissolved oxygen, heavy
atoms, temperature and pH.
- Explain
relationship between fluorescent intensity and concentration leading to
quantitative methods of analysis
- Discuss
sources of deviation from linearity for fluorescence including
self-quenching and self-absorption
- Explain
the difference between Excitation and Emission Spectra.
- Describe
the typical components and arrangement of a typical spectrofluorometer.
- Describe
the components used for phosphorimetry.
- Discuss
standardization of fluorescence instruments
- Discuss
methods of analysis in molecular luminescence including the use of
fluorescent derivatives and measurement of luminescent lifetime.
- Use
calibration curve and standard addition methods of analysis for
concentration determination from luminescence measurements
Chapter
16 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the various types of molecular vibrations and the factors that lead to
infrared radiation absorption.
- Describe
and utilize mathematical relationships from the classical and quantum
mechanical models for molecular vibration to calculate vibrational
frequencies.
- Calculate
the number of normal modes of vibration for linear and non-linear molecules.
- Describe
vibrational coupling and its consequences.
- Discuss
various components of infrared spectrometers.
- Explain
time and frequency domain spectroscopy
- Describe
the frequency problem in time domain IR spectroscopy and a Michelson
interferometer.
- Use
mathematical relationships to relate interferogram to source frequencies.
- Use
mathematical relationships to calculate resolution in Fourier transform
instruments.
- Compare
dispersive and Fourier transform IR spectrometers.
Chapter
17 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
various sample handling techniques for solids, liquids, and gases in
infrared spectrometry including attenuated total reflectance.
- Discuss
and show how infrared spectra can be used for qualitative analysis
- Discuss
and show how infrared spectra can be used for quantitative analysis
including instrumental deviations leading to non-linear response.
Chapter
18 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the mechanism leading to Raman and Rayleigh scattering, including
definition of virtual state, leading to Stokes and Anti-Stokes shifts.
- Compare
the factors that lead to Raman spectra with infrared spectra.
- Describe
the components of a typical Raman spectrometer.
- Convert
frequency shifts in Raman spectra to wavelength for a given source.
- Explain
how a depolarization ratio is determined in Raman and the information
gained.
Chapter
19 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
how a proton NMR spectrum arises quantum and classical descriptions,
including calculation of transition frequency and influence of magnetic
field strength.
- Use
Boltzman calculation for population of excited state.
- Describe
saturation and relaxation processes in NMR
- Describe
Fourier transform in NMR.
- Describe
environmental influences to NMR signals including chemical shift and
spin-spin splitting.
- Discuss
decoupling techniques in NMR
- Describe
the components of a typical FT-NMR.
- Describe
the purpose of locking and shimming an NMR spectrometer.
- Describe
and show how NMR can be used for qualitative analysis.
- Apply
NMR theory to carbon-13 nuclei.
- Discuss
application of 2-D NMR to structure elucidation.
Chapter
11 Student competencies
Upon completion of this chapter, students should
be able to:
- Define
the mass-to-charge ratio and the calculation of exact mass to isotope
specific substances.
- Describe
the typical components of a mass spectrometer.
- Describe
the mechanism of mass separation in a quadrapole, time-of-flight, and
double-focusing mass spectrometer.
- Discuss
how ICP has been coupled with mass spectrometry, and the function of the
ICP.
- Discuss
various spectroscopic interferences encountered in ICP-MS.
Chapter
20 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
electron impact, chemical ionization, field ionization, MALDI,
electrospray, and FAB ionization in mass spectrometry, including various
types of samples and information likely to be gained from each method.
- Describe
the mechanism of mass separation in a magnetic sector
- Calculate
resolution in mass spectrometry.
- Describe
ion trap mass analyzers including ion cyclotron resonance in Fourier
transform mass spectrometers.
- Discuss
and show how mass spectra can be used in qualitative analysis taking into
account isotope ratios.
- Discuss
mass spectrometry in hyphenated techniques such as gas and liquid
chromatography.
Chapter
21 Student competencies
Upon completion of this chapter, students should
be able to:
- Describe
the underlying processes involved in Auger and ESCA Spectroscopy for the
analysis of surfaces.
- Describe
special sample handling techniques used in surface analysis.
- Use
quantitative calculations for determination of binding energy.