Phenobarbital determination and its kinetic analysis by a surface plasmon resonance sensor with an immobilized antibody

Phenobarbital could be determined by using a surface plasmon resonance (SPR) sensor with a thin gold metal immobilized monoclonal antibody. This method was based on a change in the refractive indexes on a gold surface by an immunoreaction. Phenobarbital in pure water was determined within 1 ppb similar to 1000 ppm. Phenobarbital in urine could be determined by the standard addition method without any interference due to urine impurity. The detection limit of phenobarbital in human urine was 0.1 ppm in this method. A kinetic analysis gave the association constant (k(a) = 2.7 x 10(-6) M-1 s(-1)) and the dissociation constant (k(d) = 8.6 x 10(-4) s(-1)). This SPR method was sensitive and useful for crime investigations.