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55 Cards in this Set
- Front
- Back
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Relationship between wavelength and frequency |
Inversely proportional; the greater the frequency the shorter the wavelength
E=hc/wavelength |
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Spectrum for visible light |
400-700nm |
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Absorbance and transmittance are related |
linearly |
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Relationship between %Transmittance and concentration |
inversely logarithmic |
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Solving for Absorbance |
2-log(%T) |
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solving for % transmittance |
10^(2-A) |
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Beer's law |
A=Ebc |
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Monochrometer |
isolation of individual wavelengths of light |
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Bandpass |
width of the narrow band of light that actually reaches the cuvette |
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What is more sensitive Photomultiplier Tube or Photodiodes |
PMT; photodiodes lack internal amplification |
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Flame emission photometry is used for? |
Measuring sodium, potassium, and lithium
Most labs have switched to ion-selective electrodes
energy given off is directly proportional to conc in samples |
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Components of a Flame photometer |
Atomizer, Flame, Air and gas supply, monochromators, detector, readout |
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Double beam in space vs Double beam in time |
Space: 2 beams, 2 detectors
Time: 1 beam, 2 detectors |
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Part of a Spectrophotometer |
light source, monochromator, slit, sample, detector, recorder |
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Nephlometry |
measures scattered light |
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Turbidimetry |
measures amount of blocked light |
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Stokes shift |
difference in energy between the excitation light and emission light |
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Singlet state |
spin of the excited electron pair is in opposite directions |
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Triplet |
electrons are in an unpaired condition |
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Phosphorescent light is in what state |
triplet T1 to S0 |
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S1 to S0 transition |
Fluorescence |
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Sensitivity of different tests |
spec<fluorescence<chemiluminescence |
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Chemiluminescence requires |
luminometer |
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Excitation light sources |
Mercury- 365-366nm line spectra Xenon arc -uv continuum Quartz-halogen-near UV Lasers-to specific wavelength |
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Uses of IR |
secondary structures of proteins |
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Incident light |
IO enters the slide at 100% what ever is not absorbed is reflected and measured
R=Ir/Io |
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Assayed controls |
values are provided for the expected mean and SD
2SD must still be est |
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Unassayed controls |
no values are provided for mean or SD |
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ROM |
range of means-analyzer values should fall within 2SD |
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Chromatography |
separation of compounds based on their differing affinities for the mobile and stationary phases |
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Uses of chromatography |
separation purification identification |
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Eluent |
the carrier that moves the chemical through the column |
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Effluent |
mobile phase containing the solutes that have exited the chromatographic system |
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Eluate |
material emerging from the comlumn |
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Eluted |
removed from the chromatographic system |
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Adsorption |
solute and solvent are attracted to the polar sites on the stationary phase |
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Partition |
Separation based on salute partitioning, based on relative solubility, between two liquid phases
Polar stationary phase Non polar solvent |
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Choosing an ion exchanger |
pH must be determined first
the net charge of the protein at the selected pH determines the choice of ion exhcnager |
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Increasing ionic strength |
releases bound solute molecules by displacement |
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Changing pH |
alters the strength of the interaction by changing the charge of the solute and/or resin |
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Stationary phase in paper chromatography |
water-coated cellulose |
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Mobile phase paper chromatography |
liquid differs depending on the separation desired |
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Retention factors |
ratio of the migration distance of the solute from its application point to its leading edge/ to the migration distance traveled by the mobile phase from the application point |
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TLC V Paper |
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GC separation |
based on the partition coefficient of each solute which is related to its affinities for the mobile and stationary phases |
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Parts of a GC |
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What is splitless injection used for |
small sample amounts |
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Temps in GC |
Injection port 50 deg higher than component boiling point
detector 10 deg higher than the column
Temp of the column determines the retention time and resolution |
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Capillary columns |
Polyimide coating fused silica tubing stationary phase |
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Liquid phases |
Non-polar liquids are non-selective and separate based on solute volatility
Polar liquids separate based on interactions |
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Most stable GC detectors |
TC and flame |
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Flame ionization detector |
effulent is ignited producing ions
Ions conduct electricity, changes in flame current are measured |
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TC |
Wheatstone bridge temp dependent electrical resistance of a hot wire
Organic vapors will decrease temp and the thus decrease electrical resistance |
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Qualitative information |
compare peak positions with those of standard |
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Quantitative assessment |
relative concentrations of components is obtained from peak area comparisions |
