| abstract |
The present invention relates to an optical H + -sensor, comprising an H + - indicator material, wherein the H + -indicator material is present between a support material and a H+-permeable layered structure, the layered structure comprising an H + -permeable hydrophilic layer and an H + -permeable cation exchange layer. Further, the invention relates to a method for determining the H + concentration, e.g. expressed as p H, in a product or sample thereof, the method comprising contacting the product or sample with an optical H + -sensor according to the invention, measuring an optical property of the indicator material, and determining the H + -concentration of the product or sample based on said optical property. |