Abstract: A competitive immunoassay based on surface plasmon resonance (SPR) for the detection of 2,4-D has been developed. The assay is based on the regeneration of the chip surface by the reversible interaction between a monosaccharide (0-glucose) and a lectin (Concanavalin A). The interaction between anti-2,4-D antibodies and surface-bound Concanavalin A-2,4-D conjugate was monitored by SPR and the response was used for the quantification of 2,4-D. The chemiluminescent reactions of peroxidases and alkaline phosphatase, with luminol and CSPD, respectively, have been exploited in multianalytical TELISA approaches to the simultaneous analysis of different pesticides: 2,4-D; 2,4,5-T; atrazine and simazine. Statistical assays were conducted in two different formats using a COD camera and a flow injection system. Covalent chemistries were applied for directed coupling of either the antibodies or their Concanavalin A conjugates to the surface. Both competitive and non-competitive (sandwich) ELISA5 have been used. Using molecularly imprinted polymers instead of antibodies, FIA and microformat binding assays analogous to competitive enzyme immunoassays have been developed. In one example 2,4-D was labelled with a transgenic tobacco perioxidase, and the chemiluminescent reaction of Luminol was used for detection. This demonstrated for the first time that an ELISA-like assay based on molecularly imprinted polymers could be comparable with a classical antibodybased ELISA