SUPERCRITICAL-FLUID EXTRACTION OF MONONITRATED POLYCYCLIC AROMATIC-HYDROCARBONS FROM TEA - CORRELATION WITH THE PAH CONCENTRATION

The ability of supercritical fluid extraction (SFE) to extract nitropo lycyclic aromatic hydrocarbons (nitro-PAHs) from tea matrices is descr ibed and discussed. An experimental approach was set up to determine t he influences of various extraction parameters, i.e. pressure, tempera ture, extraction time and addition of modifier. The evaluation of the method was carried out by analysing samples of fortified tea and then comparing the results with those obtained from conventional extraction procedures, such as Soxhlet extraction and ultrasonication. SFE prove d to be far better than the conventional methods at monitoring levels of nitro-PAHs in tea. However, due to the wide range of polarity of th e analytes investigated, selective extraction with supercritical carbo n dioxide was not possible; hence, subsequent purification steps were necessary, prior to the final GC/MSD analyses. The nitro-PAHs and PAHs concentrations in several tea samples were determined, any correlatio n between nitro-PAHs and PAHs was studied and the results are presente d in this article.