Unresolved complex mixture
Appearance

Unresolved Complex Mixture (also UCM or hump) is a feature frequently observed in gas chromatographic (GC) data. The reason for its appearance is that gas chromatography cannot resolve and identify a significant part of the hydrocarbons in crude oils. The resolved components appear as peaks while the UCM appears as a large background/platform. In non-biodegraded oils the UCM may comprise less then 50 % of the total area of the chromatogram, while in biodegraded oils this figure can rise to around 90 %. UCM is also observed in certain refined fractions such as lubricating oils ([1] and references therein).
See also
References
- ^ Gough, M. A. & Rowland, S. J. (1990) Characterization of unresolved complex mixtures of hydrocarbons in petroleum. Nature 344, pp. 648-650