Abstract: By combining HTHS sampling with GC separation, a method for the confirmation and quantification of residual hydrocarbons having a number of carbon atoms ranging from 5 to 8 in edible oil samples has been developed and tested. The sample was heated at 90 ℃ to achieve equilibrium and increase the transfer of residual hydrocarbons into the headspace, and then, a 25% squalane packed-column was used to perform the isolation and determination. The results showed that no interferences were noted within 0.5h equilibrium. The repeatability of the analytes (expressed as a relative standard deviation, RSD) for simulant sample is: <0.2 % for retention time and <5 % for peak area, the total recovery 99.2%, and LOQ (limit of quantitative) less than 0.5mg/kg. The equilibrium model, chromatographic separation model and quantitative method lead to a significant difference between the new method and the current GB method. The making-up of standard solution of No.6 solvents from different resources definitely affects the quantification of analytes by GB method. The achieved method may better be used to follow variations of residual solvents during vegetable oil manufacturing process and to detect the quality of refined oil.

Key words: vegetable oil, residual solvents, high temperature headspace (HTHS ), separation, gas chromatography (GC)