TNT Detection Using Multiplexed Liquid Array Displacement Immunoassays

Abstract

The presence of trace contamination of soil and groundwater with explosives is an ongoing concern, for which improved methods are required to facilitate their detection and quantification. This is true both for the monitoring of remediation and for site characterization. Immunosensors have been found effective for solution-phase detection of environmental contaminants. Our work utilized the Luminex100 (flow cytometer) to detect TNT in a multiplexed displacement immunoassay format. The Luminex100 can perform a multiplexed assay by discriminating between up to 100 different bead sets. We used this capability to evaluate four different TNT monoclonal antibodies, two recombinant TNT antibodies, and a control antibody simultaneously for the rapid detection of TNT and other nitroaromatics. TNT could be detected at 0.1 ppb and quantified over the range of 1.0 ppb to 10 ppm. In addition, the assay was shown to be effective in various matrixes such as lake water, seawater, and acetone extracts of soil. Seawater required dilution with two parts buffer to avoid loss of microspheres, while the acetone extracts were diluted 100-fold or more to minimize solvent affects.

Self-assembled nanoparticle arrays for multiphase trace analyte detection

“…Various analytical techniques exist that can be used for molecular detection of pollutants 1,2 , explosives [3][4][5] , narcotics 6,7 , and pesticides 8 . Often "real-samples" contain a complex mixture of compounds, which need to be quantified.…”

The application of single particle aerosol mass spectrometry for the detection and identification of high explosives and chemical warfare agents

“…12 Explosives are commonly identified using colorimetry, 13 UV-absorption spectroscopy, 14,15 laser-induced fluorescence (LIF), 16,17 immunoassay, 18 ion mobility spectrometry (IMS), [19][20][21][22][23] and mass spectrometry (ion trap and time-of-flight (TOF)). [24][25][26][27][28][29][30][31][32][33] It should be noted that research into explosives detection is performed on gas, liquid, and/or solid phase explosives, and that the sampling methods and concepts of operation vary widely between the different techniques.…”

“…Anderson et al used this technique for the detection of TNT. 18 Antibodies specific for antigen/TNT were immobilized onto latex microspheres and treated with fluorescently labeled trinitrobenzene (TNB) which bound to the antibody. When TNT was introduced to the beads, it displaced the TNB, and the reduction in the fluorescence signal was quantitated.…”

“…6 Others, such as LIF, require consumables or extensive sample preparation that reduces their viability for fast analyses and may reduce the selectivity of the measurement. 18 Although other mass spectrometry …”

Displacement Immunosensor Based on Surface Plasmon Resonance for Rapid and Highly Sensitive Detection of 2,4,6-Trinitrotoluene

“…Luminex (flow cytometer)-based displacement immunoassay has also been reported. (11) That sensing system is not based on the flow system or the displacement reaction in the well on a microtiter plate, and 15 min of incubation time was required.…”