A capillary electrophoresis method was developed for the analysis of Class IV caramels using sodium carbonate buffer at pH 9·5. A relationship was established between the migration time of the coloured ‘caramel’ peak and the caramel's sulphur content. There was also a linear relationship between the concentration of caramel solids in water and the peak area of the ‘caramel’ peak in the range 0·1–10 g litre−1. A range of soft drinks was analysed for caramel. Seven non-diet and 12 diet cola products had Class IV caramel of high-sulphur, high-nitrogen content at concentrations estimated to be between 0·57 and 0·82 g solids litre−1. © Crown Copyright 1998.