Preparation and Optimization of Optical pH Sensor Based on Sol-Gel

Abstract

Making use of the sol-gel technique, an optical pH sensor was prepared, which was made from an organic carrier with four indictors including congo red, bromophenol blue, cresol red, and chlorophenol red, cross-linked by tetraethyl orthosilicate (TEOS) and cellulose acetate. The actual detection range of the optical pH sensor is 2.5–11.0. The optimal ratio of ethyl orthosilicate, absolute ethanol, deionized water, and hydrochloric acid in glue precursor of the sensor-sensitive membrane was explored. The orthogonal experiment was designed to optimize the dosage of cellulose acetate, N,N-dimethylformamide (DMF), indicator, hydrochloric acid, and precursor glue in preparing the sensor-sensitive membrane. The linearity, measurement accuracy, repeatability, stability, and response time of the prepared pH sensor were tested. The measurement results were analyzed using a support vector machine and linear regression. The experimental results show that the optical pH sensor has a measurement accuracy of up to 0.2 pH and better stability and repeatability than the traditional pH glass electrode.

A simplified methodology: pH sensing using an in situ fabricated Ir electrode under neutral conditions

“…Optical pH sensors usually consist of a pH indicator immobilised on an organic carrier. The indicator changes its chemical structure after interacting with H + ions, which leads to a variation of its optical response as a function of pH [35]. However, because the response of the colour change is sigmodal with pH, the accuracy is constrained and the useful detection range can be relatively narrow, often being 2-4 pH units only [36].…”

Recent advances in cellulose-based membranes for their sensing applications

“…Zhang Jianxin fabricated an optical pH sensitive membrane via sol–gel method, which was developed by embedding four indicators of congo red, bromophenol blue, cresol red and chlorophenol red into an organic carrier, simultaneously cross-linked by tetraethyl orthosilicate (TEOS) and cellulose acetate (Zhang and Zhou 2018 ). According to a linear relationship between Power (µW) and pH values, a working detection range (2.5–11.0) was obtained, with a measurement accuracy (0.2 pH) of the sensor.…”

A new soft tissue constructed with chitosan for wound dressings-incorporating nanoparticles for medical and nursing therapeutic efficacy

“…One of the primary limitations is their inability to provide information about wound healing and environmental conditions, including temperature, humidity, or inflammation. These factors significantly impact the wound healing process, and controlling them is necessary to accelerate healing [ 27 , 28 ].…”