Non-conventional electrochemical and optical sensor systems

Electroanalytical methods are a common tool for the assessment of chemical peculiarities of aqueous solutions. Also, the analysis of water based on optical sensors is a mature field of research, which already led to industrial applications and standard laboratory practices. Nevertheless, scientific literature is still offering new sensor techniques and innovative measurement approaches in both fields. In particular, for fast characterisation of liquids and change detection applications in a continuous monitoring context, the technology of taste sensors based on electrochemical techniques is still witnessing a growing interest. Such devices are often defined as "electronic tongues" or "e-tongues". In addition, emerging inexpensive and portable devices with optical-sensing capabilities can be used for monitoring applications with a novel approach. This chapter gives an overview of recent techniques developed in both fields and presents several potential applications and case studies that deal with the context of water quality assessment. A brief introduction about the basics of each measurement technology, even if not exhaustive, is also provided.