etc

• anything smaller than 400 nm is ultraviolet light
• anything larger than 700 nm is infrared light
• band pass - the actual range of wavelengths that pass through a test solution; all wavelengths hitting a sample
• target wavelength - largest quantity of wavelengths hitting sample
• %T

  A) I

  B) Io

  C) 100

  
• concentration vs %T

  A) concentration

  B) %T

  
• absorbance vs concentration

  A) Absorbance

  B) Concentration

  
• absorbance

  A) 2

  B) -

  C) log(%T)

  
• A=

  A) E

  B) b

  C) c

  
• A=Exbxc

  E(epsilon) = molar absorptibity
• A=Exbxc

  B - length of light path through solution
• A=Exbxc

  C- concentration of the absorbing molecules
• formula for unknown concentration

  A) unknown

  B) absorbance of unknown

  C) standard

  D) absorbance of standard

  
• turbidimetry properties

  • blocks light as well as scatters it
• • Nephelometry
  • Measures light scatter
• nephelometry benefits

  • minimizes errors due to color
• • Fluorometry spectra
  • Excitation spectra aka excitation maxima
  • Wavelength of light that wil produce maximum # of excited electrons
  • Use this term instead of incident light
• fluorometer spectra

  • Emission spectra
  • Wavelength of light emitted on return to ground state
  • Instead of emitted light
• fluorometer spectra

  • Stokes shift
  • The difference between the emission and excitation “maxima” or wavelength
• • dvantages of fluorometry
  • Only need a small sample volume
  • Cost effective - dealing with light not chemicals
  • High specificity and sensitivity
• fluorometry

  • Disadvantages:
  • Sensitive to environmental changes
• fluorometry sensitivity to environment

  • Change in temperature - electrons collide with each other instead of jumping to next higher shell
  • Causes Loss of either electrons or fluorescence (caused by loss of electrons)
• fluorometry sensitivity to environment

  • Changes in pH - changes availability of electrons
• fluorescence polarization

  • radiant=emission
• fluorescence polarization

  • incident = excitation
• fluorescence polarization is used for therapeutic drug use
• FPIA - fluorescent polarized immunoassay
• • Ion selective electrode now used - electrode that has coating on it that will only allow target ions through membrane; uses electricity to determine concentration of that particular ion
• atomic absorption spectrophotometry

  • both sensitive and precise
• in atomic absorption spectrophotometry, a radio frequency is used to excite the elements in the bulb emitting light specific to the element we are testing
• • Zone electrophoresis - what is commonly used in clinical laboratory to track the migration of macromolecules 
• agarose gel and polyacrylamide gel do not have a net charge
• cellulose acetate may have a net charge
• Electroendosmosis - interference or influence of gel that has its own net charge
• the filter of a densitometer may be used to select wavelength of light
• densitometer

  A) lamp

  B) slit

  C) filter

  D) sample

  E) detector

  F) recorder

  
• chemiluminescence -

  • Fluoresence but instead of using light, use chemical (usually an oxidant) to give off light
• chemiluminescence theory

  • oxidant added to sample
  • analyte decays
  • gives off radiant energy
• • Bioluminescence - uses an enzyme called luciferase 
  • Ultrasensitive; subject to interferences 
  • Used on a limited basis
  • Sometimes in immunoassays, but fluorescence is preferred
• thin layer chromatography is a type of liquid chromatography