Development of a one-step integrated pressurized liquid extraction and cleanup method for determining polycyclic...

A rapid and accurate one-step integrated pressurized liquid extraction (PLE) and cleanup method was developed and validated for 34 polycyclic aromatic hydrocarbons in marine sediments, giving an extract that could be analyzed by gas chromatography-mass spectrometry without further cleanup. Marine sediment (5 g) was loaded into the stainless-steel extraction cell above activated copper (5 g) and activated silica gel (5 g). An extraction temperature of 100°C and two 5 min extraction cycles using a 4:1 (v/v) hexane-dichloromethane mixture gave a good extraction efficiency. The integrated method gave extracts that were as clean as those obtained using PLE, followed by separate activated copper and silica gel cleanups. The method was validated, in terms of its accuracy, precision, and application using a certified reference material (NIST SRM 1944), marine sediments spiked at low and high concentrations, and contaminated harbor sediments. The mean recoveries were 92% and 94% for the low and high spike concentrations, respectively, and the accuracy was good (giving a mean of 86% of the certified reference material concentrations). The method developed gave a precision and accuracy equal to or better than the precision and accuracy found using PLE with separate cleanups. The method developed gives a shorter sample preparation time and uses much less solvent than PLE and separate cleanups.