To obtain a univocal identification we need two independent analytical information. Main flavour and fragrance components prior to gas chromatographic separation are usually identified with MS spectral comparison and linear retention indices (LRI).

Even using this two information diastereomeric or positional isomers can present identical retention behaviour and MS spectrum, thus it can cause misidentification. The development of a unique condensed phase FTIR provide the solution using the GC to separate the components and FTIR spectrometer to give structural elucidation in a single analysis.