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Real-Time Biosensor for the Detection Of Trace Levels of TNT in Aquatic Environments

May 24, 2007 By: Peter Adrian


This content is excerpted from Sensor Technology Alert and Newsletter, a sensor intelligence service published by the Technical Insights unit of Frost & Sullivan.

Sensor Technology Alert

Toxic pollutants have always been a source of concern to the health of aquatic bodies. Ranging from the release of chemicals to oil spills, the effect of such events, particularly in terms of their impact on the population of aquatic species, have alerted us of the degree of harm they can have on the overall ecosystems. As a result, the capability to detect the presence of such pollutants has been a key concern for various government and nongovernment organizations.

Trinitrotoluene, or more commonly known as TNT, is a major source of hazardous water pollution and is produced through military installations involved in manufacturing, storage, and handling of munitions. Past research has proved that TNT contamination occurs via surface water runoff or ground water inflow and has been found to be particularly detrimental to benthic invertebrates, fish, and plants. TNT detection techniques include the use of high-pressure liquid chromatography (HPLC) coupled with ultraviolet (UV) detection, immunochemical methods, and many others. The technique based on HPLC has a number of drawbacks such as its high cost, and inability of real or near-time assessment at low concentrations. Additionally, the Environmental Protection Agency (EPA) has its own method for the detection of TNT, which is based on using antibody-based detection systems. This process has a fixed sensitivity and specificity criteria for investigators using it. However, all these techniques can have drawbacks either in terms of the speed of detection or sensitivity.

Researchers from Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary have worked on a project with Sapidyne Instruments Inc., Boise, ID to develop and assess a biosensor to detect TNT in near real time in aquatic samples. The KinExA (Kinetic Exclusion Assay) sensor developed by Sapidyne Instruments Inc. is a highly sensitive TNT immunosensor that consists of a specific monoclonal antibody coupled with a prototype fluorescence-based detector system. The detection technology is based on fluid phase interaction of the target with a specific antibody and detection of fluorescence inhibition.

The developed biosensor has proven to be reliable in the test trails to identify a wide range of TNT concentrations. Further developments are envisioned and include reagent cooling and an in-built computerized control system. This would provide on-site capabilities to carry out autonomous assessment of pollutant concentrations. The impact of particulate matter and dissolved organic carbon on the system's performance is also seen as a probable area of research.






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