Novel sensor devices and monitoring strategies for green and sustainable chemistry processes

The principles of green chemistry include a statement as to the necessity for realtime analysis for prevention of pollution. Methodologies need to be developed for real-time, in-process monitoring and control prior to the formation of hazardous substances. These should be carried out by (chemical) sensors. Monitoring also allows optimizing the efficient use of reagents and permits determination of the composition of waste and effluents. In this paper, new monitoring strategies are surveyed and some of the recent advances which have been achieved with respect to novel devices in terms of miniaturization and reliability are indicated. Emphasis is given to continuous and online flow and injection methodologies and the requirements for successful sensors. Particular attention is given to the future potential of electrochemical flow and batch injection sensors which can often be used without external sample pretreatment. Electrochemical sensors using carbon film-based electrodes, including their application in room-temperature ionic liquids (RTILs) for which electrochemical methodologies are directly suited are also described.