Sensor: The Evolution Of Chemical Sensors

INTRODUCTION:

1. Sensor: A sensor is a device which detects and measures a physical property and responds to it. Sensors are classified into –chemical sensors and physical sensors. A molecular sensor or chemical sensor is a device that interacts with the analyte to produce a detectable change. The evolution of chemical sensors is an active area in analytical research. Physical sensors are mainly to detect physical responses. Biosensors are also type of chemical sensor used to sense the biological activity of proteins, nucleotides, tissues. Sensor consists of receptor and transducer parts.

The chemical sensor provides information about the chemical state of the process. It consists of an active sensing material and signal transducer. A sensor generally has

For static quenching τ0=1 , τ for Dynamic quenching F0 =τ0 . F τ

Static quenching affects absorption spectra of fluorophore while dynamic quenching affects only the excited state of fluorophore. At high temperature, dynamic quenching is high as collision is fast while static quenching is low.

Dynamic quenching: At the excited state quencher fuses into fluorophore and returns to ground state without emission of a photon. The decrease in fluoroscence intensity caused by dynamic quenching is explained by Stern-Volmer equation: F0 = 1 + kqτ0[Q] = 1+KD[Q]