Use of a programmed temperature vaporizer for off-line SFE/GC analysis in food composition studies

A simple procedure is proposed for off-line supercritical fluid extraction and capillary gas chromatography using a programmed temperature vaporizer (PTV) injector. The independent control of flow and temperature of the supercritical fluid is achieved by means of a variable restrictor (i.e., nozzle). The described system combines some advantages of the on-line coupling SFE/GC (high sensitivity and reduced sample handling) and the off-line approach (simpler performance and depressurization outside the chromatographic column). The proposed procedure and the solvent recovery method used to collect the extracted analytes are applied to the analysis of the essential oil obtained from Rosmarinus officinalis L. Also, a comparative study with the extracts obtained by using the simultaneous distillation extraction technique (SDE) is presented.