A Fluorescence Intensity Ratiometric Fiber Optics–Based Chemical Sensor for Monitoring pH. Issue 12 (17th September 2018)

• Record Type: Journal Article
• Authors: Rosenberg, Martin; Laursen, Bo W.; Frankær, Christian G.; Sørensen, Thomas Just
• Is Part Of: Advanced materials technologies. Volume 3:Issue 12(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-17
• Subjects: fluorescent dyes -- optical pH sensor -- pH optode -- porous sol–gels -- sensors; Materials science -- Periodicals; Technological innovations -- Periodicals; Materials science; Technological innovations; Periodicals; 620.1105
• DOI: 10.1002/admt.201800205
• Languages: English
• ISSNs: 2365-709X

Abstract

Abstract: Accurate determination of pH is essential, yet a single technology is relied upon for almost all pH measurements. Here, a new optical pH sensor is described. Two highly photostable fluorescent dyes with a polymerizable side chain are incorporated into a composite polymer that allows for fast transport of protons. A pH‐responsive dye and a reference dye with limited response to pH are used, thus allowing for determining pH using a ratiometric fluorescence intensity response. The sensor material—dyes covalently attached in the composite polymer—is deposited on a polycarbonate hemiwicking substrate, and immobilized on the inside of a shaker flask. In this manner, two robust pH optodes with p K a values of 5.30 and 6.11 are prepared. The pH‐responsive composite materials are addressed using fiber optics, and the response is recorded on a fiber spectrometer. The optodes are shown to have low drift, fast response time, no leachables, and the sensor is shown to work in heterogeneous media exemplified with coffee, beer, and cola. Abstract : Biocompatible and chemically stable optical sensors that enable robust and noninvasive measurements of pH are presented. The sensors rely on the intensity ratiometric response to pH of two highly photostable, fluorescent triangulenium dyes. The sensor performance is characterized and shows that these optical pH sensors can be used in the range from pH = 3.8 to pH = 7.6.