Micro-plasma emission detector unit and method

A micro-plasma emission detector unit for use with a gas chromatograph, the detector unit including:

• an airtight housing made of a monolithic block of a transparent material and having an internal ionization chamber, the housing including a carrier gas inlet and a gas outlet that are in fluid communication with the ionization chamber through internal passageways, the housing further including a makeup gas inlet and a makeup gas inlet chamber, the makeup gas inlet chamber being in fluid communication with the carrier gas inlet upstream the ionization chamber, and at least one light collection window area in registry with the ionization chamber;
• a pair of spaced-apart ionization electrodes provided in the housing and positioned on opposite sides of the ionization chamber;
• and
• a permeation device containing a semi-permeable membrane, the semi-permeable membrane being at least partially and removably insertable inside the makeup gas inlet chamber.