Surface Plasmon Resonance (SPR) is a resonant charge density oscillation that can occur at the interface of two media with dielectric constants of opposite signs, for instance, a metal and a dielectric, when p-polarized light strikes the surface. Under the condition of total internal reflection an evanescent wave is formed. If the energy and momentum of the photons is right, the photons are converted to plasmons, reducing the intensity of the reflected light at a specific angle. This angle is called the resonance angle and is highly sensitive to any change of the boundary between the two media, allowing precise measurements of thin film properties as well as monitoring of molecular interactions in real-time.
The SPR instrument at Chalmers Materials Analysis Laboratory (CMAL) is the BioNavis SPR Navi 220A. This instrument is a so called multi-parametric SPR enabling measurements on a number of samples, surfaces and conditions that are not possible with traditional SPR instruments. Full angular reflectivity spectra can be measured. Measurements can be performed on polymers, metals, alloys, ceramics and organic layers, ranging from a few Ångström to at least one micron in thickness. The measurements can be done in air or liquid phase. It is possible to measure physical properties such as thickness, swelling and adsorbed mass as well as optical properties and electrochemical behaviour. Furthermore, real time molecular interactions can be detected, including kinetics, on and off rates, adsorption, desorption, affinity and concentration determinations.
The instrument can be booked here. For more information, please contact Research Engineer Katarina Logg.
• True goniometric SPR with rotating lasers
• Laser wavelengths: 670 nm and 785 nm
• Two optical channels
• SPR angle range 40-78°
• Refractive index range: 1.00-1.40 (bulk)
• Sensitivity: 1μRIU (Refractive Index Unit)
- corresponds to 50 ppm change in
reflectance signal in the fixed angle mode
• Noise level: 1 μRUI
• Electrochemical flow cell
• Chemical resistant flow cell
• Temperature: 15-40°C