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Final Decision to Certify Hazardous Waste Environmental Technology


(Trinitrotoluene in Water and Soil)

Certification No: 95-01-017

Technology Description:

The Ohmicron TNT RaPID Assay System uses enzyme-linked immunosorbent assay (ELISA) technology. It differs from other systems in that polyclonal antibodies are supplied attached to magnetic particles. TNT in water is assayed directly; for soils, the system uses extraction with alkaline methanol. The immunoassay system is semi-quantitative. Provided that the materials are used properly, detection is possible at 0.25 to 5.0 ppb in water and 0.25 to 5.0 ppm in soil; ranges can be extended upward by dilution of the extracts. Quantitative readings about a selected target level are obtained in a microprocessor-equipped, hand-held, battery-operated photometer or a compact table top photometer supplied by the manufacturer, or a standard laboratory photometer. The calibration is not biased, but the user is instructed to select target levels so as to determine the degree of confidence in avoiding false negative results. The reaction with other nitroaromatics is insignificant except for 1,3,5-trinitrobenzene (a contaminant in technical grade TNT), HMX, RDX, Dinoseb, 2,4-dinitrophenol, and mononitroaromatics do not interfere. Differences in the extraction efficiency of TNT from various soils may cause positive or negative errors in the immunoassay results. Users should evaluate these factors before attempting to quantify results.

Great care is required and established safety measures must be observed in sampling and handling soil containing explosives. As with similar assays, certain temperature controls are required for reagent storage and for carrying out the assay. The assay should be used only by trained individuals to reduce operator-caused variability.

Issued to:
Ohmicron Environmental
Diagnostics, Inc.
375 Pheasant Run
Newtown, PA 18940
Mr. Paul Georgantas or
Mr. Charles Mamrak
Effective Date:
March 4, 1996
Expiration Date:
March 4, 1999
DTSC Contact:
Dr. Wolfgang Fuhs
(510) 540-3076

A copy of the published Certification Notice may be obtained by contacting us at:

Department of Toxic Substances Control
Office of Pollution Prevention and Technology Development
P.O. Box 806
Sacramento, California 95812-0806
Phone: (916) 322-3670
Fax: (916) 327-4494
e-mail: techdev@dtsc.ca.gov

File last updated: October 9, 1996

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