Absorbance, transmittance, emission, limitations

Absorbance, transmittance, emission, limitations

1. Absorbance

   • Sample absorbs specific wavelengths energy
     • Used for identificaiton
     • Absorbance spectrum
       • Difference in energy
     • Incident radiation passed through the sample
       • of range of wavelengths introduced
     • Transmitted radiation is emitted from sample
       • Wavelengths not absorbed pass through sample (transmitted)
       • Absorbance spectrum- peaks at wavelengths absorbed

2. Transmittance

   • Similar to absorbance
     • Same process
     • Same equipment
     • Transmittance spectrum
   • Spectrum is of transmitted radiation
   • Transmittance spectrum-troughs of wavelengths absorbed

3. Emission

   • Absorbed energy quickly lost
   • Emission radation
   • Different wavelength (energy) to absrobed
   • Specific radiation for sample compound or elements
   • Emission spectrum- peaks at emission wavelengths

4. Limitations

   • Components of mixtures not separated
   • Separate compounds/elements of interest
     • Chemical reaction
     • Separation
   • Contamination
   • Interference
   • Measures to limit their influence on analysis