Performance Evaluation and Comparison of Four SPR Immunoassays for Rapid and Label-free Detection of TNT

A simple and highly sensitive surface-plasmon-resonance (SPR) immunoassay has been demonstrated for rapid and label-free detection of 2,4,6-trinitrotoluene (TNT). The immunoreaction between a home-made polyclonal anti-2,4,6-trinitrophenyl-keyhole-limpet-hemocyanine antibody (P-TNPh-KLH Ab) with a physically immobilized TNPh-ovalbumin (TNPh-OVA) conjugate was utilized for TNT quantification based on the principle of indirect competitive immunoreaction. The performance of the P-TNPh-KLH Ab was compared with three commercially-available antibodies and was observed that the home-made antibody exhibited the highest sensitivity to TNT (1 ppt) among the other antibodies with a response time of 2 min.