How do the electron capture detector work?

Hint: First of all we should know about the electron capture detector and also about an electron. An electron is a negative charged particle. Electrons are important as they take part in chemical bonding and a lot of compounds are formed due to the sharing or transferring of an electron.

Complete step-by-step answer:
The electrons which occupy the outermost shell of an atom are generally referred to as valence electrons. These electrons generally determine how an atom will react.

Characteristics of an electron
-An Electron is a negatively charged particle.
-They generally revolve around the nucleus within various energy levels.
-By absorbing the energy they can be excited to a higher energy level.

Mass of the electron is just $\dfrac{1}{{2000}}$ times of proton/neutron.

About electron capture detector:
Electron capture detector is a device which is generally used for detecting atoms and molecules in a gas through the attachment of electrons by using electron capture ionization.

Working of Electron capture detector device-
When a gas is passed through the electron capture detector, some electrons of certain molecules are captured when they pass through the detector and the current which is being measured is reduced, this results in a positive peak being recorded.

Note: The common use of the electron capture detector is generally in the environmental testing for the detection of the organochlorine pesticide, herbicides and about various hydrogenated hydrocarbons. A beta emitter like radioactive tritium or 63 Ni is used to ionize the carrier gas.