Detection of surfactants using surface plasmon resonance sensor for screening of pesticide residue

The positive list system for pesticide residues in food was introduced in Japan in 2003. Under this system, the number of regulated pesticides has increased, and a long-time analysis of pesticide residues is required. A new assay method for detecting pesticide residues more efficiently is also required. In this study, we developed a screening method for the detection of pesticide residues using a surface plasmon resonance (SPR) sensor. Self-assembled monolayers (SAMs) were formed on the sensor surface using alkanethiols. Surfactants were used as auxiliary agents in pesticides. The adsorption characteristics of the surfactants were investigated using the SPR sensor with a SAM-modified surface. We used an eicosane thiol SAM for a nonionic surfactant and an N, N,N-trimethyl(16-mercaptohexadecyl)ammonium (C16-TMA) SAM for an anionic surfactant. As a result, a detection limit of 30 ppb was achieved for imazalil and glyphosate with the anionic surfactant and a detection limit of 80 ppb was achieved with the nonionic surfactant using the SPR sensor.