BRAINCAKEAnalytical Techniques
Revision notes for Analytical Techniques in OCR Chemistry A (H032). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Infrared SpectroscopyInfrared (IR) spectroscopy is an analytical technique used to identify the bonds, and so the functional groups, present in an organic molecule.
- Bond Vibrations and IR AbsorptionCovalent bonds are not rigid.
- Characteristic IR AbsorptionsEach type of bond absorbs in a characteristic range of wavenumbers.
- Interpreting IR SpectraTo interpret an IR spectrum, look for a small number of key absorptions rather than trying to explain every trough.
- IR in Breathalysers and Pollution MonitoringIR spectroscopy can measure how much of a substance is present, as well as identify it.
- Mass Spectrometry of Organic CompoundsA mass spectrometer is used to find the relative molecular mass of an organic compound and to give information about its structure.
- The Molecular Ion PeakThe molecular ion peak, M+, is produced by molecules that have lost one electron but have not broken apart: M(g) → M+(g) + e− Because the molecular…
- The M+1 PeakLook closely at a mass spectrum and you will usually see a very small peak one unit to the right of the molecular ion peak.
- FragmentationMolecular ions are often unstable and break apart in the mass spectrometer.
- Combining IR and Mass SpectraNo single technique proves the structure of an unknown compound.