title: Improved ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons in sediments.
abstract: The aim of this work was to optimize an ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons (PAHs) in sediments and to compare it with the reflux procedure using methanolic potassium hydroxide. Sample extracts were purified with a miniaturized silica gel chromatographic column and analyzed by gas chromatography-mass spectrometry (GC-MS). Ultrasonication using n-hexane-acetone (1:1, v/v) solvent mixture on dried homogenized marine sediment gave better precision (smaller relative standard deviation (RSD) values) and comparable quantities of individual PAH's compared to the reflux procedure. Ultrasonication with the n-hexane-acetone (1:1, v/v) mixture, utilizing four 15 min extraction cycles, was found to be sufficient for extracting PAHs from wet sediments. The optimized ultrasonic extraction procedure extracted aliphatic and aromatic hydrocarbons from the National Institute of Standards and Technology SRM 1941a with recoveries greater than 90%. The major advantages of ultrasonication compared to the reflux method are the lower extraction times, simplicity of the apparatus and extraction procedure. The optimized ultrasonication procedure has been used in our laboratory to extract hydrocarbons from naturally wet sediments from rivers, and coastal and marine areas.
authors.affiliation: Department of Marine Analytical Chemistry, Institute of Marine Affairs, Hill Top Lane, Chaguaramas, P.O. Box 3160, Carenage Post Office Trinidad and Tobago, West Indies. dbanjoo@ima.gov.tt
authors.forename: Darryl Ricardo
authors.initials: DR
authors.lastname: Banjoo
authors.forename: Paul Kurt
authors.initials: PK
authors.lastname: Nelson
mesh_terms: D000096:Acetone; D008401:Gas Chromatography-Mass Spectrometry; D006586:Hexanes; D006878:Hydroxides; D000432:Methanol; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D017680:Potassium Compounds; D012680:Sensitivity and Specificity; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis; D012997:Solvents; D014465:Ultrasonics
chemical_list: D006586:Hexanes; D006878:Hydroxides; D011084:Polycyclic Aromatic Hydrocarbons; D017680:Potassium Compounds; D012987:Soil; D012989:Soil Pollutants; D012997:Solvents; D000096:Acetone; C026385:n-hexane; C029943:potassium hydroxide; D000432:Methanol