Absorbance based light emitting diode optical sensors and\ud sensing devices

摘要

The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this,\udappropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and\udcompatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical\udsensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements.