E F Schipper | PubMed Health

PubMed1998

The waveguide Mach-Zender interferometer as atrazine sensor.

Immunoanalytical techniques used in combination with a highly sensitive Mach-Zender waveguide sensor give a device that is capable of fast on-line monitoring of immunoreactions. The on-line monitoring is especially attractive when the sensor can be used as an environmental probe. It is demonstrated that low concentrations of atrazine can be measured with a sensitivity around the EC limit of 100 ng/L. These measurements are performed with an inhibition technique. In combination with "a dynamic slope method" one complete measurement is done within 10 min. Sensor measurements show the same sensitivity and errors as parallel ELISAs.

Atrazine↗

PubMed1996

The critical sensor: a new type of evanescent wave immunosensor.

A new planar waveguide immunosensor has been developed in which adsorption at a surface, changing the refractive index contrast, is measured. In this "critical" sensor the change in the effective refractive index contrast is transducted to a shift of the critical reflection angle. The sensor's theoretically. In addition, an experimental sensitivity evaluation on the basis of several immunosensing experiments is presented. The obtained lower detection limit is 2 x 10(-2) nm in adlayer growth, equivalent to 12 pg/mm2 of analyte coverage. This sensitivity is comparable to the performance of the surface plasmon resonance sensors or the grating coupler sensors. However, the "critical" sensor has some advantages. These are mainly the ease of fabrication and adjustment prior to a measurement, and the fact that for an experiment no metal layer has to be used.

Antigen-Antibody Reactions↗