What are the two main types of electrochemical cell used as gas sensors? Discuss the main features of each type. Briefly explain how each of the following work and what they are typically used for:...

What are the two main types of electrochemical cell used as gas sensors? Discuss

the main features of each type.

Briefly explain how each of the following work and what they are typically used

for: (a) catalytic gate field effect transistor gas sensor, (b) metal oxide gas sensor,

(c) infrared gas sensor, (d) mass spectrometer.