The two heterocyclic compounds 2 - and 4(5)-methylimidazole (2 - and 4-MI) have been the focus of interest in recent years because of their potential carcinogenic properties and their occurrence in various foods such as cola, iced tea, dark beer, soy sauce and caramel colour. They occur in small quantities as by-products of the Maillard reaction and are found in higher concentrations in ammonia- and ammoniumsulfite-caramel colour. The State of California introduced a NSRL (No Significant Risk Level) of 29 g/day for 4-MI because of its possible toxic properties. The presence of 2-MI in food, however, is not yet sufficiently clarified.This thesis aims to provide an overview of the presence and the generation of the two substances in foods. A suitable method for the chromatographic separation and detection of 2- and 4-MI by HPLC was developed. The isolation and the quantification of the chemicals from various food matrices were carried out by solid-phase extraction or ion-pair extraction and following HPLC separation and UV-Vis detection. Samples of cola, coffee, ammonia- and ammoniumsulfite-caramel colour were used. While the recovery rates from these foods were adequate, showing that the extraction was successful, in the native sample 4-MI was found only in ammoniumsulfite caramel. The reason for that might be the low sensitivity of the UV detector.With the aid of model systems, consisting of a constant source of carbohydrate (glucose), and a variable amine source, the formation mechanism of 2- and 4-MI were examined in more detail. The aqueous model systems were heated and Maillard reaction was stopped at different time points. It is very clear to see that the amine source exerts a pivotal influence on the formation of the substances. While 4-MI could be quantified in several model system, 2-MI was only detected in model 10, using glutamine as the substrate. In general with the duration of heating time, the formed amounts of analytes increased in all models.