Characterization of a fast response fiber-optic pH sensor and illustration in a biological application

• Published in: Analyst (London) 2021-08, Vol.146 (15), p.4811-4821
• Main Authors: Werner, Jan, Belz, Mathias, Klein, Karl-Friedrich, Sun, Tong, Grattan, K. T. V
• Format: Article
• Language: English
• Subjects: Biomonitoring; Drift; Dyes; Environmental monitoring; Fiber optics; Hydrogels; Leaching; Optical measuring instruments; Optics; Response time; Retinal cells; Sensors; Stability
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d1an00631b

Optical, and especially fiber-optic techniques for the sensing of pH have become very attractive and considerable research progress in this field has been made over recent years. The determination of the value of pH across a broad range of applications today, important for areas of study such as life sciences, environmental monitoring, manufacturing industry and widely in biological research is now accessible from such optical sensors. The need for such technology arises because familiar, commercial sensors are often limited in terms of their response time and the presence of drift, all of which emphasize the value of newer and rapidly developing technologies such as fiber-optic sensors, to address these wider applications. As a result, a new compact sensor design has been developed, designed around a specially-formed fiber-optic tip, coated with a pH-sensitive dye, and importantly covalently linked to a hydrogel matrix to provide high stability. The sensor developed was designed to have a very fast response time (to 90% of saturation, Δ t 90 ) of