n-hexane

2,5-Hexanedione (2,5-HD), the main metabolite of n-hexane was extracted from urine samples using cold fiber head space solid-phase microextraction (CF-HS-SPME) based on thermoelectric cooling and analyzed with gas chromatography equipped with a flame ionization detector (GC-FID). Important parameters for improved efficiency of fiber sorption including sample volume, extraction time and temperature were optimized using a central composite design. The optimum conditions were determined, under which the detection limit and the relative standard deviations were found.

The results of the research of extraction of oil from the none-crushed and crushed sunflower seeds of different fractions by the method of extraction are presented. The mechanism of extraction and process kinetics is investigated. It has been shown that the process of extracting oil from sunflower seeds is complex and consists of both intra-diffusion and external-diffusion transfer of oil. It is stated that the process is similar to the extraction of the target components from the seeds of most types of plant raw materials.