Chemistry 407-408
Integrated Physical and Analytical Chemistry
bowling green state university chemistry department
course description
Chemistry 407-408 is a laboratory course, normally completed by chemistry majors during their junior year. Normally students take physical chemistry (Chemistry 405-406) at the same time. Although students will have taken a classical analytical course, they will not normally take the lecture course on instrumental analysis until their senior year.
The course meets each week for two three hour labs and a one hour common period. There are normally two sections and each section is limited to ten students. Students work directly with a senior faculty member who is present throughout the period and who directly grades reports. Typically students work in pairs and each experimental module requires two periods. A written report is required for each experiment completed.
The course is intended to cover a wide range of topics, instruments and techniques. It is, in fact, the only required laboratory course beyond Organic Chemistry. As a result, we include topics which we feel are needed in the curriculum, even if they are not formally Physical or Analytical chemistry. The only other advanced laboratory course in our curriculum is a one semester Biochemistry Lab and a Materials Science survey course with lab.
experimental modules
The first semester begins with an introduction to most of the basic analytical instruments. Where possible physical chemistry topics are introduced at points comparable to that of the lecture course.
- Spectrophotometry
- diode array spectrometer
- Beer's Law
- Fe3+/SCN- equilibrium
- Ni2+/ ethylene diamine complexes: extracting spectra
- extensive use of spreadsheets
- High Performance Liquid Chromatography
- instrument performance, parameters
- analysis of analgesic mixture
- Gas Chromatography
- packed columns, thermal conductivity detector
- parameters: flow rate, column temperature
- separation, resolution and quantification (usually simple hydrocarbon mixture)
- Electronics: Operational Amplifiers
- construct and test inverting and noninverting amplifiers, summing circuits, integrators, active and passive filters.
- use thermocouple, pH electrode, phototransistor (assemble direct reading thermometer and pH meter.)
- use digital oscilloscope, digital multimeter, x-y recorder, oscillator.
- The OP AMPS are part of a McKee Pedersen unit. This same ensemble is used later in the year to construct virtual instruments (including cyclic voltammetry.)
- Liquid-Vapor Binary Phase Equilibrium
- Collect liquid and vapor samples from a refluxing binary liquid
- Analyze the two phases using quantitative gas chromatography
- Construct a phase diagram.
- Gas Chromatography-- part II
- capillary column, flame ionization detector
- emphasis is on use of internal standards
- Includes a working session with GC-MS instrumentation and data.
- Atomic Absorption and Atomic Emission Spectrometry
- Flame AA, AES Instrument
- Analysis at trace amounts
- Emphasis on standards; standard additions method
- Surface Adsorption
- Gas/Surface adsorption using a vacuum line
- Library Project
- Solution Conductivity
- generally determine equilibrium constant
- Electrical Cells and Potentiometry
- actual procedure varies considerably
- Semiempirical and
Ab Initio Molecular Calculations
- includes normal mode analysis
- generally paired with a gas phase IR study of the same molecule
- Synthesis and Properties of Polyacetylene
- inert atmosphere synthesis from acetylene and liquid catalyst
- IR spectrum of polymer film (cis- and trans- iosmers; fully deuterated forms)
- Visible spectrum and electrical band gap or thin films
- doping and electrical conductivity
- IR Gas Phase Spectrum and full Vibration/Rotation Analysis
- generally diatomic: HCl, DCl (HBr, CO)
- often include H2O, CO2, C2H2
- parameter of FT-IR spectrometers
- usually include additional spectra in the near IR (overtones)
- Gas Phase Spectrum of I2 vapor
- full anharmonic vibrational analysis; calculation of bond energy
- use scanning spectrophotometer; study of factors affecting resolution
- Kinetics: Stop Flow Kinetics
- generally do Fe3+, SCN- as function of H+
- Kinetics-- Oxidation of Ascorbic acid
- followed spectrophotometrically
- temperature dependence, energy of activation
- effect of ionic strength
- Computer Interfacing
- We use a conventional interface board (ADC, DAC, binary I/O lines)
- Programs are written in QuickBasic
- A library of interface routings are available
- Write a program to log a signal vs time (ADC, timer)
- we often log the redox potential during an oscillating reaction
- Write a program which generates a simple external signal (DAC)
- Virtual Instrument-- Cyclic Voltammetry
- Use Op Amp breadboard to construct circuitry for three electrode CV
- Use DAC to generate and vary the potential (linear sweep)
- Use ADC to monitor current at the working electrode
- Plot multiple sweeps (including erasing prior scans)
- (A particularly interesting application is to oxidize a solution of aniline using a transparent electrode (tin oxide on glass.) During a sequence of sweeps one can see the appearance of new peaks. After about 5 minutes the electrode shows a change in color. During a sweep, one can observe the color change from blue to green to yellow. This color change can occur in 2-5 seconds. If desired, the sample can be oxidized to a specific state, removed, and the visible absorption spectrum can be recorded.)
- Fluorescence Spectra, Lifetime
- pulsed laser spectroscopy (methyl viologen)
- lifetime vs concentration of quencher
- NMR Spectrometry
- FT-NMR
- experiment varies: kinetics, structure, intermolecular interactions
- Optional: Semiconductor Nanoclusters
- synthesis of CDs with control of cluster size
- control via micelles or control via adsorption
- color (spectra) of materials
Instrumentation-- chemistry 407-408
Most of the instruments are part of the instructional laboratory suite. Others (marked with #) are part of a larger departmental instrument pool. items marked (*) were purchased, in part with NSF Instructional or Instrumentation Grants.
- Spectrophotometer: HP8452A Diode Array Spectrometer (gift of HP Corporation)
- Spectrometer: Ocean Optics fiber optic diode array spectrometer (*)
- Spectrophotometer, Scanning UV-Vis (Beckman Acta-M-IV)
- Atomic Absorption Spectrometer (replacing with Buck xxxx, 1997)(*)
- #FT-IR Spectrophotometer: Mattson Galaxy 2000
- #FT-near IR Spectrophotometer: Mattson xxxx
- IR Spectrometer, scanning (PE 1400)
- #NMR Spectrometer --Varian, -- MHz, with --- (*)
- HPLC-- Hewlett Packard Model xxxx (Spectrophotometric detector) (*)
- GC--HP ### (Packed column, thermal conductivity detector, locally produced data system)
- GC--HP ### (Capillary column, thermal conductivity detector) (*)
- GC- HP ### (Packed column, FID and Electron Capture GC) (*)
- (*)GC-MS Hewlett Packard ####
- Tracor Purge and Trap GC accessory (not in use) (*)
- Pulsed Laser System (PTI Nitrogen Laser PL2000/ PTI Dye Laser PL202) (*)
- Digital Storage Oscilloscopes
- Nicolet (1 microsecond/point)
- Tektronix TDS380-- 400 MHz (0.5 nsec/point)
- Other instruments used on occasion in the course
- Differential Scanning Calorimeter
- Spectrofluorometer
- Electrochemical System: (used for CV)
- Scanning Electron Microscope Facilities
- X Ray (Powder) Diffraction Facilities
- ORD Spectrometer
- HPLC-MS
- Ultracentrifuge
- Spectrophotometer-- UV-Vis Cary 219
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