Improved method for the storage of groundwater samples containing volatile organic analytes

Archives of environmental contamination and toxicology (1999-02-27)
Kovacs, Kampbell
RESUMO

The sorption of volatile organic analytes from water samples by the Teflon septum surface used with standard glass 40-ml sample collection vials was investigated. Analytes tested included alkanes, isoalkanes, olefins, cycloalkanes, a cycloalkene, monoaromatics, a polynuclear aromatic, and two chloroethenes. Both laboratory prepared test mix solutions and petroleum contaminated groundwater from three field sites were tested. A rapid loss of n-alkane and isoalkane concentrations (>10%) was observed within 24 h when stored at room temperature. Aliphatic losses were also observed (>10%) over a 21-day holding period when samples were held at 4 degrees C. Loss of the less sorptive analytes was demonstrated by exposing analyte solutions to greater Teflon surface areas. The demonstrated sorption of aliphatics from water samples by Teflon-lined septa indicates that the accuracy of volatile petroleum hydrocarbon determinations may be reduced by the traditional storage method. An alternative storage protocol is reported combining a lead foil septum surface and 1% (w/w) tribasic sodium phosphate dodecahydrate (Na3PO4. 12H2O) preservative. This method prevented loss of the test analytes, including alkanes and isoalkanes for at least 21 days at room temperature.

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Lead, foil, 150x150mm, thickness 0.5mm, as rolled, 99.95%
Lead, foil, 50x50mm, thickness 0.25mm, as rolled, 99.95%
Lead, foil, 50x50mm, thickness 0.1mm, as rolled, 99.95%
Lead, foil, 100x100mm, thickness 3.0mm, as rolled, 99.95%
Lead, foil, 100x100mm, thickness 3.0mm, as rolled, 99.99+%
Lead, foil, 100x100mm, thickness 6.0mm, as rolled, 99.99+%
Lead, foil, 150x150mm, thickness 0.125mm, as rolled, 99.95%
Lead, foil, 150x150mm, thickness 0.15mm, as rolled, 99.95%
Lead, foil, 150x150mm, thickness 0.1mm, as rolled, 99.95%
Lead, foil, 150x150mm, thickness 0.25mm, as rolled, 99.95%
Lead, foil, 150x150mm, thickness 0.55mm, as rolled, 99.999%
Lead, foil, 150x150mm, thickness 1.0mm, as rolled, 99.5%
Lead, foil, 150x150mm, thickness 1.0mm, as rolled, 99.95%
Lead, foil, 250x250mm, thickness 3.0mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.125mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.125mm, as rolled, 99.99+%
Lead, foil, 25x25mm, thickness 0.15mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.1mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.25mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.25mm, as rolled, 99.99+%
Lead, foil, 25x25mm, thickness 0.55mm, as rolled, 99.999%
Lead, foil, 25x25mm, thickness 0.5mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 0.5mm, as rolled, 99.99+%
Lead, foil, 25x25mm, thickness 1.0mm, as rolled, 99.5%
Lead, foil, 25x25mm, thickness 1.0mm, as rolled, 99.95%
Lead, foil, 25x25mm, thickness 1.0mm, as rolled, 99.99+%
Lead, foil, 25x25mm, thickness 1.5mm, as rolled, 99.99+%
Lead, foil, 25x25mm, thickness 3.0mm, as rolled, 99.99+%
Lead, foil, 300x300mm, thickness 0.125mm, as rolled, 99.95%
Lead, foil, 300x300mm, thickness 0.15mm, as rolled, 99.95%

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