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Troubleshooting

(Note: the two problems discussed on this page often (but not always) occur simultaneously)

Problem: My spectrum has "spikes" between 4000 - 3500 and/or 2000 - 1500 cm^-1 (water vapour).

• there is a discrepancy between the amount of water vapour in the air of the background spectrum and your sample spectrum. The causes for this include
   
  1. your background spectrum is too old - record a new background spectrum immediately before recording the sample spectrum (the humidity changes constantly around the instrument)
  2. an air bubble has become trapped between the salt plates (affects thin film, Nujol mull, and solution spectra)
  3. you accidentally exhaled into the sample compartment as you closed the door when recording either your background spectrum or your sample spectrum

Problem: My spectrum has a (possibly inverted) double peak between 2380 - 2290 cm^-1 (carbon dioxide).

• there is a discrepancy between the amount of carbon dioxide in the air of the background spectrum and your sample spectrum. The causes for this include
   
  1. your background spectrum is too old - record a new background spectrum immediately before recording the sample spectrum (the CO₂ level changes constantly around the instrument)
  2. an air bubble has become trapped between the salt plates (affects thin film, Nujol mull, and solution spectra)
  3. you accidentally exhaled into the sample compartment as you closed the door when recording either your background spectrum or your sample spectrum

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Last modified: Monday, February 28, 2011
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