Topic world Gas chromatography

Selective GC detector for trace analysis of halogen and sulphur compounds

The Echelle Plasma Emission Detector (EPED) is an element-specific detector for the selective analysis of halogen and sulphur compounds. It is more robust and sensitive than the comparable element-specific atomic emission detector (AED). Contrary to an MS detector, quantification can be performed using an equimolar response, i.e. easy determination of concentration in complex matrices without primary standards. The analytes are introduced directly after the GC column into the plasma cell, a quartz glass tube with pulsed high-frequency helium plasma. This direct transfer prevents adsorption effects to a great extent, which is particularly essential for quantification in fluorine analysis. To avoid soot formation, the plasma is switched off during the solvent peak (solvent delay), which increases long-term stability and sensitivity of the detector. Quantification is based on the emitted light energy, which is detected by a CCD camera and is directly proportional to the concentration over a wide concentration range.