simulant and water, e.g. electron spin resonance (ESR) 151, which requires structure identification of individual substances responsible for detected ESR signals Synthetic mixtures of additives (antioxidants, UV stabilizers) used in the manufacture of food packaging materials were separated by normal phase HPLC under isocratic or gradient elution, and by capillary SFC using CO, as mobile phase. SFC proved to be more eff icient for the separation and determination of additives with a wide range of boiling points and for substances lacking a UV chromophoric moiety. Combined SFC/MS, using a direct coupling interface, produced clear charge transfer spectra resembling El spectra and proton exchange CI spectra when ammonia was added to the ion source.