Electrochemiluminescence Enzyme Immunoassays for TNT and Pentaerythritol Tetranitrate

Department of Chemistry, Liverpool University, Liverpool L69 7ZD, UK.
Analytical Chemistry (Impact Factor: 5.64). 09/2003; 75(16):4244-9. DOI: 10.1021/ac034163s
Source: PubMed


Electrochemiluminescence enzyme immunoassays for 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN) are described. The latter is, to the best of our knowledge, the first report of an immunoassay for PETN. Haptens corresponding to these explosives were covalently attached to high-affinity dextran-coated paramagnetic beads. The beads were mixed with the corresponding Fab fragments and the sample. After adding a second HRP-labeled antispecies-specific antibody, the mixture was pumped into an electrochemiluminometer where beads were concentrated on the working electrode magnetically. The amount of analyte in the sample was determined by measuring light emission when H2O2 was generated electrochemically in the presence of luminol and an enhancer. The detection limits for TNT and PETN were 0.11 and 19.8 ppb, respectively. Details of bead preparation and performance are given. The increase in sensitivity obtained when Fab fragments are used instead of whole antibodies is explained, and the implications of this observation for nanoparticle-based assays are discussed.

    • "The antibody was briefly mentioned in a paper by Blackburn et al. (Blackburn et al., 2000); however, no details were given. The monoclonal antibodies were used by Wilson et al. (Wilson et al., 2003) for an electrochemiluminescence enzyme immunoassay reaching a detection limit of about 20 μg/l and some other work (Aojula et al., 2002). The hapten design for PETN antibodies is particularly difficult, because the molecule shows high symmetry and does not offer any site for chemical modification. "
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    ABSTRACT: An improved antibody against the explosive pentaerythritol tetranitrate (PETN) was developed. The immunogen was designed by the concept of bioisosteric replacement, which led to an excellent polyclonal antibody with extreme selectivity and immunoassays of very good sensitivity. Compounds such as nitroglycerine, 2,4,6-trinitrotoluene, 1,3,5-trinitrobenzene, hexogen (RDX), 2,4,6-trinitroaniline, 1,3-dinitrobenzene, octogen (HMX), triacetone triperoxide, ammonium nitrate, 2,4,6-trinitrophenol and nitrobenzene were tested for potential cross-reactivity. The detection limit of a competitive enzyme-linked immunosorbent assay was determined to be around 0.5 µg/l. The dynamic range of the assay was found to be between 1 and 1000 µg/l, covering a concentration range of three decades. This work shows the successful application of the bioisosteric concept in immunochemistry by exchange of a nitroester to a carbonate diester. The antiserum might be used for the development of quick tests, biosensors, microtitration plate immunoassays, microarrays and other analytical methods for the highly sensitive detection of PETN, an explosive frequently used by terrorists, exploiting the extreme difficulty of its detection. Copyright © 2015 John Wiley & Sons, Ltd.
    No preview · Article · Oct 2015 · Journal of Molecular Recognition
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    • "Notwithstanding various analytical methods have been used for the sensitive determination of NB, including fluorescence, high-performance liquid chromatography, gas chromatography and luminescence [11] [12] [13] [14] [15], the electrochemical methods have more advantages such as low-cost, highly sensitive and user friendly than that of aforementioned traditional methods [16]. More recently our group has found that green synthesized metal nanoparticles have excellent electrocatalytic ability toward nitro group substituted aromatic compounds owing to its high stability, conductivity, biocompatibility, low cytotoxicity and size-related electrochemical properties [17]. "
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    ABSTRACT: The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10 min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV-vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600 mu M with high sensitivity of 1.01 mu A mu M-1 cm(-2) and low limit of detection of 0.016 mu M. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples.
    Full-text · Article · Aug 2014 · Journal of Hazardous Materials
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    • "Fully Electrical Microarrays 267 explosives, biological toxins and antibiotics is the main goal (Pestka, 1991; Beier and Stanker, 2000; Loomans et al., 2003; Wilson et al., 2003; Estevez–Alberola and Marco, 2004; Lee et al., 2004). To achieve high sensitivities, physical test methods like high-pressure liquid chromatography (HPLC) or gas chromatography with mass detection (GC–MS) are enabled (Sorensen et al., 2003). "

    Full-text · Chapter · Jan 2005
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