A thermal desorption gas chromatograph/mass spectrometer (TDGC/MS) has been evaluated for on-site detection of polychlorinated biphenyls (PCB) In soll/sedlment. The MS was operated In the selected Ion monitoring mode for the simultaneous detection of PCB congeners 1-8, octachlorinated naphthalene, and deuterated polycyclic aromatic hydrocarbon standards. The linearity of the detector was established over 3 orders of magnitude of compound thermally desorbed. Methods were developed which provided screening level (semlquantitatlve) analyses In 2-5 min/sample and more quantitative analyses In less than 20 mln/sample (Including sample preparation time). Method detection limits were established at sub ppm levels. A commercially purchased PCB standard soli was evaluated to determine method performance In the field. Approximately 35 ppm PCB was found In the soil by thermal desorption from a hexane extraction; soil certified to be 35 ppm PCB, Aroclor 1242. The TDGC/MS was transported to a U.S. Environmental Protection Agency (EPA) hazardous waste (Superfund) site and operated by battery. Several samples were collected and compared between laboratory GC/MS and field TDGC/MS measurements. Findings Indicate that the field methods provide data quality comparable to methods mandated by the EPA for the analysis of soils as prescribed by Superfund.
Qecent years have marked a shift in the U.S. public perception of and policy toward environmental contamination and hazardous waste production, treatment, and disposal. Legislation and changing public attitudes have altered the emphasis from expedient waste disposal to waste reduction, treatment, and remediation of contaminated sites. As a result, by the year 2020 more than 3000 national Superfund sites may be listed by EPA, with cleanup costs in excess of $150 billion [1-3). Moreover, the facility and landfill cleanups for the Department of Energy (DOE) and Department of Defense are estimated to exceed $2 trillion and $100 billion, respectively. DOE estimates that it will spend $15^5 billion for analytical services over the next 30 years.The current sample volume for hazardous constituent analyses exceeds 400,000 samples per year, and analytical costs at some of the larger DOE sites are in excess of $10 million annually (4).Site characterization-one of the most important components of the cleanup process-is conducted before, during, and after remediation, with analytical costs accounting for up to 80% of site delineation and 50% of remediation expenses (3).Current environmental sampling and analysis methods are time consuming, costly, and present potential exposure hazards to workers and the community. Measurement of environmental contaminants in the field can be preferable to laboratory analysis. The savings in time translate into cost savings by reducing the need for remobilization of field crews, and improved characterization resulting from "real-time," interactive sampling decisions. In addition, manipulation during sample collection, transportation, and storage can affect the sample integrity and thus the analytical results. Therefore, where possible, in-situ measurements of environmental contaminants in soil, water, and waste are preferred if they meet the data quality objectives and are cost competitive.Field analytical methods (FAMs) are designed to cheaply and rapidly produce data of sufficient quality to meet data quality objectives in nearreal time. We review here the state of the art and the application of gas chromatography/mass spectroscopy (GC/MS) FAMs. This important organic analytical technique is a prime example of the trend in several areas of chemical and physical measurements of taking the measurement to the sample and providing information rapidly to facilitate decision making. Advantages of field analytical methodsFAMs range from adaptations of accepted laboratory methods with identical data quality objectives and documentation requirements to various screening methods. The latter include methods in which compound classes, not specific compounds, are identified; in which data quality objectives are consistent with project requirements; and in which documentation requirements are abbreviated. The field
A Polyporus sp. generated characteristic oakmoss flavour components such as methyl 2,4-dihydroxy-3,6-dimethyl benzoate (evernyl, methyl p-orcinate), 2-hydroxy-4-methoxy-6-methyl benzoic acid (everninic acid), 3-hydroxy-5-methyl phenol (orcinol) and 3-methoxy-2,5-dimethyl phenol (p-orcine monomethylether) when grown in submerged culture. Volatile compounds were isolated from the culture medium by solvent extraction and an adsorption technique. Gas chromatographic methods and, because certain compounds were not sufficiently volatile or too unstable at elevated temperatures, a specially developed HPLC method were applied to characterize the fungal metabolites. As well as oakmoss components, the Polyporus sp. produced many other volatiles, such as the sesquiterpene 7p-hydroxydihydrodrimenin, phenolics, and aliphatic alcohols.
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