INO has developed a novel fiber optic chemical sensor technology based on ion-selective membranes. This sensor relies on the membrane’s absorption spectrum, which depends on the concentration of a target ion. The membrane is used as the cladding when deposited on a multimode fiber, which guides the signal. The uniqueness of this technology comes from the fact that the concentration of ions in the solution is monitored via evanescent wave spectroscopy. This configuration allows concentration measurements in colored or even opaque solutions, since the light propagating in the core only interrogates the membrane and never “sees” the medium under testing. Moreover, the membrane composition can be adjusted to detect different ions.
Our ion-selective fiber technology is available for technology transfer.
Patented design to optically interrogate the ion-selective fiber cladding
Spectral analysis methods for calculating ion concentrations
Custom-tailored membrane composition to
improve sensor lifetime
adjust sensor pH range
adjust sensor sensitivity
Insensitivity to electromagnetic interference
Measurements in opaque solutions
Fast response time
Low-cost disposable probe, no recalibration required
Custom-tailored system for multi-ion or multi-site detection
By combining chemical membrane spectroscopy expertise with our extensive optical system design and development know-how, we can adapt the platform to specific client applications and requirements.
Pulp and paper
Chemically or physically aggressive media
The actual membrane is composed of a plasticized PVC lipophilic matrix incorporating a pH sensitive dye, some ionic sites, and an ionophore selective to a particular ion. The membrane is thus selective to the target ion present in an aqueous solution. The ionophore, bound to the specific ion, will cause the dye to release a proton and change its absorption spectrum. This spectral change is then measured and correlated to the target ion concentration. The membrane, constituted with the same basic components, can be rendered sensitive to a given application. Several ion-selective membranes have already been developed (Na+, Ca2+), and the ion-selective fiber (ISF) platform is compatible with multi-ion detection.