Sensitive detection of 2,4,6-trinitrotoluene by surface plasmon fluorescence spectroscopy

We developed a compact measurement system for surface plasmon fluorescence spectroscopy (SPFS) and a sensor surface for the detection of 2,4,6-trinitrotoluene (TNT). We employed a laser diode as a light source in the optical system for exciting fluorescence. Then, a fan-shaped beam was irradiated from the laser diode to a Au thin film using a beam expander. Fluorescence emission was captured using a photomultiplier detector. The sensor surface was modified with TNT analogues via a self-assembled monolayer. A limit of detection in the ppt range for TNT was obtained using a fluorescence-labeled anti-TNT monoclonal antibody in the SPFS system by indirect competitive assay.