Polycyclic Aromatic Hidrocarborbons (PAHs) represents one of the major categories of pollutants formed during incomplete combustion of organic matter. The sediments of mangroves have unique features such as high productivity, abundance of debris, high concentrations of organic carbon, making this environment highly complex and vulnerable to anthropogenic contamination. The aim of the present work is optimize an analytical procedure for extraction, separation and detection of 16 USEPA priority pollutant polycyclic aromatic hydrocarbons (PAHs). The separation methodology of the standard solution including the 16 PAHs was developed, using HPLC/UV/Vis and a reverse phase C-16 column. Many parameters were studied such as the solvent composition, flow rate, isocratic and gradient elution. The separation and quantification by gradient elution is more effective in the determination of the 16 PAHs. The best results were obtained with elution gradient that started at 50% CAN, remain fixed for 5 minutes and then slowly increases the percentage of CAN until the value reaches 85% during 50 minutes analysis. Ultrasonic extraction technique were applied and different time periods were tested (10, 15 and 20 minutes). The recovery efficiency of the PAHs was equivalent for all the solvents tested and the best time for extraction was 20 minutes. In this study, three different solvents (acetone, methanol and acetonitrile) were tested. Acetone was the best solvent among the three solvent tested during the extraction of PAH in sediment 16, followed by methanol and acetonitrile. The optimized method was applied in two sediment cores that were took out in Lagoa Salina near Bragança city. The results shown that among the PAHs detected only 6 have a concentration above the limit of detection. The naphthalene was the PAH that exhibited the higher concentration (0,231 and 0,238 mg/kg dry weight).
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