The Recent Advances in Bulk and Microfluidic-Based pH Sensing and Its Applications

Abstract

The determination of pH is of paramount importance in environmental, pharmaceutical, and medicinal sciences, etc., for accurate controlling, monitoring, and adjusting whole processes on microscale and macroscale. Therefore, the pH measurements have drawn continuous efforts from a great deal of research. The bulk pH determination can tackle part of the demands from laboratories and industrial applications. However, more and more studies have started to pay more attention to microfluidic-based pH sensing by integrating with metal oxides and solid-state-based pH sensing applications. This review paper focuses on the recent development of pH sensing, the mechanisms of pH sensing, a few common pH sensors, and microfluidic-based pH determinations from the aspects of fabrication techniques to the various applications in biology, environmental study, and food safety. The future trends of pH sensing, as well as microfluidic-based pH sensing, were discussed as well at the end of this review.