Determination of polycyclic aromatic hydrocarbons in marine sediments by high-performance liquid chromatography after microwave-assisted extraction with micellar media.
A simple and rapid method is developed for extraction and determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. The procedure was based on the microwave-assisted extraction of PAHs in marine sediment samples using a micellar medium of Polyoxyethylene 10 lauryl ether as extractant. Two-level factorial designs have been used to optimize the microwave extraction process. The analysis of extracts has been carried out by HPLC with UV detection. Fortified sediments gave an average recovery between 85.70 and 100.73%, with a relative standard deviation of 1.77-7.0% for PAHs with a ring number higher than three.
Extraction of Organic Pollutants from Solid Samples Using Microwave Energy
This study, which is part of an ongoing U.S. Environmental Protection Agency (EPA) research program, carried out by the Environmental Monitoring Systems Laboratory-Las Vegas, addresses new sample preparation techniques that (a) prevent or minimize pollution in analytical laboratories, (b) improve target analyte recoveries, and (c) reduce sample preparation costs. We present here additional evaluation results of the microwave-assisted extraction (MAE) procedure (described previously in this journal) for 187 compounds and four Aroclors listed in the EPA Methods 8250, 8081, and 8141A. Our results demonstrate that most of these compounds can be recovered in good yields from the matrices investigated. For example, recoveries ranged from 80 to 120% for 79 of the 95 compounds listed in Method 8250, 38 of the 45 organochlorine pesticides listed in Method 8081, and 34 of the 47 organophosphorus pesticides listed in Method 8141A. When recoveries from freshly spiked soil samples were compared with those from aged samples, we found that recoveries usually decreased ; as expected, there was more spread in recoveries with increased aging time. For 15 compounds in a reference soil, the recoveries of 14 compounds by MAE were equal to or better than recoveries obtained by Soxhlet extraction (naphthalene being the exception) ; for selected organochlorine pesticides, recoveries from spiked soil samples were at least 7% higher for MAE than for either Soxhlet or sonication extraction.
Sensitivity and limit of detection in quantitative spectrometric methods
In this paper, the more important definitions of the limit of detection and sensitivity will be discussed. The emphasis will be directed toward indicating the basis from which the different definitions are derived and the types of information provided by the various definitions of sensitivity and limits of detection.