Abstract

Many polycyclic aromatic hydrocarbons (PAHs) and some of their derivatives have received much attention because some of these compounds are highly carcinogenic and mutagenic. The PAHs are produced by industrial processes and the incomplete combustion of fossil fuel, as well as by forest fires. PAHs are ubiquituos and their sources are innumerable. For this motive, has been generated great interest to optimize extraction and quantification methods. The supercritical fluid extraction (SFE) has been used for PAHs extraction mainly from solid matrices. CO2 is the most common fluid used, but studies carry out indicate the extraction with modifier is much more efficient that with pure CO2. The aim of the present work was the optimization of the conditions to carry out the extraction of 16 PAHs in spiked sand samples and in certified reference material. The procedure was developed and optimized using factorial design. The use of this experimental design allows for a reduced number of experiments to explore a wide experimental range. They are more efficient than the one at a time experiments since they allow us to detect interactions between variables. Parameters studied include pressure, temperature, time and volume of methanol as modifier. A high and a low level and a central point repeated 3 times were selected for each of the factors to be optimized for the experimental design. These 4 variables were optimized with the Statgraphics program obtaining a number of 19 measurements (24+3=19). The values of the variables were the following: pressure (1000-3000 psi), temperature (40-150°C), static extraction time (0-45 min.) and volume of methanol (0-0.7 mL). The determination was realized by HPLC technique with a DAD detector.