An Optical pH Sensor Based on Diazaoxatriangulenium and Isopropyl‐Bridged Diazatriangulenium Covalently Bound in a Composite Sol–Gel

Abstract Optical pH sensing is still in its infancy due to lack of highly stable pH responsive dyes. The triangulenium fluorophores show remarkable photostability and have been demonstrated as the responsive dye in an intensity based ratiometric optical pH sensor using a fiber optical sensor hardware. Here, an optical pH sensor is reported where both the responsive dye and the reference dye are from the triangulenium family using free form optics for the hardware platform. A full spectrometer‐based sensor system consisting of sensor chemistry, hardware, and software is presented.