Surface plasmon resonance immunosensor for anionic surfactants based on an indirect competitive immunoreaction

A highly sensitive surface plasmon resonance immunosensor for the determination of linear alkylbenzene sulfonate (LAS) was fabricated. The method is based on an indirect competitive reaction of an anti-LAS antibody in a sample solution with LAS immobilized on a sensor chip and with LAS in the sample solution. A sensor chip immobilized with LAS was prepared by utilizing an electrostatic interaction between an LAS conjugate, LAS-horseradish peroxidase (LAS-HRP), and a self-assembled monolayer of 11-amino-1-undecanethiol hydrochloride, which was preliminary prepared on a gold thin film of the sensor chip. The quantitative determination of LAS in the concentration range 10-1000 ppb was achieved by using the proposed immunosensor.