Study of VOC distribution in citrus fruits by chromatographic analysis.

The contamination of various parts of citrus fruits by toluene (a representative of volatile organic compounds-VOCs) was analyzed. The model of contamination distribution, based on investigations of the sorption and accumulation of toluene in particular parts of citrus fruits was considered. Solvent extraction of components from fruit parts (waxy layer, cuticle, and pulp) was applied. The extracts were analyzed by gas chromatography. The sorption time profiles for such citrus fruits as kumquats and mandarins were determined by plotting the extracted mass, or the relationship C/C(0), versus the sorption time of toluene. After the sorption process the highest concentration of toluene was observed in the flavedo, where the oil glands of kumquats and mandarins are located. The data obtained prove that the high dissolution of aromatic hydrocarbons results from the presence of essential oils in the oil glands. The diffusion coefficients of toluene for the cuticle and pulp of kumquats were also calculated. The results of model investigations were compared with the actual concentration of toluene in kumquats, citrons, mandarins and oranges from outdoor stands and orchards.