Interpretation and identification of cryotrapping GC-FTIR spectra using conventionally recorded reference data
Interpretatie en identificatie van spectra verkregen m.b.v. "cryotrapping" GC-FTIR
Visser T , Olsthoorn M , Vredenbregt MJ
RIVM Report 502501020
The utility of literature reference data, extracted from infrared (IR) spectra recorded with conventional sample preparation methods, for the interpretation and identification of spectra obtained with cryotrapping gas-chromatography-Fourier transform infrared spectrometry, has been investigated. Spectra of 158 compounds of various structure and origin have been studied in parallel. Differences between cryotrapping IR spectra, recorded at 77K, and spectra recorded at ambient temperature, appear to be small. Most frequency shifts of functional group vibrations are in the order of the optical resoltuin (2 cm-1) and the observed intensity changes are usually small. Therefore, frequency-structure correlation tables based on conventionally recorded spectra, remain useful for the interpretation with hardly any modification. Incidentally, larger differences have been observed. These can be attributed to the phase difference liquid-solid and to crystallisation effects. The minor differences between cryotrapping and conventionally recorded IR spectra permits successful application of library search procedures in reference collections of conventionally recorded data. Spectra recorded at optical resolution of 8 cm-1, provide better results than their analogues recorded at 2 cm-1.