Determinations of N-nitrosodimethylamine at part-per-trillion concentrations in contaminated groundwaters and drinking waters featuring carbon-based membrane extraction disks
- Oak Ridge National Lab., TN (United States)
A new solid-phase extraction procedure extracts N-nitrosodimethylamine (NDMA) at part-trillion (ng/L) concentrations from aqueous samples using a C{sub 18} (reversed-phase) membrane extraction disk layered over a recently introduced carbon-based extraction disk. The reversed-phase disk removes nonpolar water-insoluble neutrals and is set aside; the carbon-based disk is extracted with a small volume of dichloromethane. NDMA is quantified in the organic extract using a gas chromatograph equipped with both a short-path thermal desorber and chemiluminescent nitrogen detector. The detection limit for the procedure, calculated using two statistically unbiased protocols, is 3 ng of NDMA/L; the analyte recovery is nearly 57%. A related procedure substitutes a standard automatic sampler for the short-path thermal desorber and is suitable for determining NDMA in heavily contaminated ($GTR@300 ng of NDMA/L) aqueous samples. The detection limit for the procedure, calculated in the same manner as above, is 300 ng of NDMA/L, with an analyte recovery of nearly 64%. The detection limits and measured recovery values are comparable to those observed in earlier work. The newer procedures described herein offer a 50-fold savings in extraction time and a 100-fold reduction in dichloromethane consumed per sample while maintaining the wide range (3-4 orders of magnitude concentrations of NDMA) observed for the original procedures used in tandem. 22 refs., 1 fig., 5 tabs.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 405337
- Journal Information:
- Analytical Chemistry (Washington), Vol. 68, Issue 15; Other Information: PBD: 1 Aug 1996
- Country of Publication:
- United States
- Language:
- English
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Determination of N-nitrosodimethylamine at part-per-trillion levels in drinking waters and contaminated groundwaters
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