Detection of TNT by a molecularly imprinted polymer film-based surface plasmon resonance sensor

A surface plasmon resonance (SPR) sensor using a molecularly imprinted polymer (MIP) film as a recognition element for detection of 2,4,6-trinitrotoluene (TNT) was developed. The TNT-imprinted polymer film was prepared by thermo initiated polymerization on the bare Au surface of an SPR sensor chip. Template TNT molecules were quickly removed with an organic solution of acetonitrile/acetic acid (9:1, v/v), causing a shift of 0.7A degrees in SPR angle. The limit of detection for TNT was demonstrated to be as low as 1x10(-8) mol/L. In the concentration range of 1x10(-8)-1x10(-5) mol/L, the change of SPR angle was linear with the negative logarithm of TNT concentration. Selectivity studies showed that the SPR sensor had no response to TNT analogues 2,4,5-trinitrotoluene and 1,3,5-trinitrohexahydro-1,3,5-triazine at a concentration of 1x10(-4) mol/L. The results suggest that the SPR sensor combined with a MIP film has the advantages of high sensitivity and selectivity, and long-term stability toward the analyte TNT.