Disposable Fluorescence Optical pH Sensor for Near Neutral Solutions

Sensors

Luca Ferrari¹  Luigi Rovati²  Paola Fabbri² 

[1] Department of Engineering Enzo Ferrari, University of Modena and Reggio Emilia, via Vignolese 905, Modena I-41125, Italy;

关键词: optical sensor;    pH sensor;    fluorescence sensor;    hydrogel;    polymer matrix;   

DOI  :  10.3390/s130100484

来源: mdpi

【 摘 要 】

The design, development and performance evaluation of a fluorescence-based pH sensor for on-line measurements is presented. The pK_a of the sensing element has been calculated to be 7.9, thus the sensor is suitable for measurement of near neutral solutions. The sensor consists of a low-cost disposable polymer sensing probe, in contact with the solution under test, interrogated by an optoelectronic transduction system. The pH sensitive dye is based on fluorescein O-methacrylate, which has been covalently linked to a hydrogel matrix, realized through the use of HEMA (2-hydroxyethyl methacrylate), HDDA (1,6-hexanediol diacrylate) and PEGDA (polyethylene glycol diacrylate). The optical interrogation setup, together with the electronics, has been developed to acquire and process the fluorescence signal. The sensor works over a pH range between 6.5 and 9.0. In the range between 7.0 and 8.0, the sensor shows a linear behavior with a maximum linearity error of 5%. Thanks to the good performance of the sensing element and transduction system, the short term drift of the reading (measured over 40 min) is lower than 0.15%. The measuring system also exhibits good performance in terms of response time and reproducibility.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.