MEMORY EFFECTS IN GAS-CHROMATOGRAPHIC DETECTION WITH A MICROWAVE-INDUCED PLASMA

Capillary gas chromatography coupled to microwave-induced-plasma detec tion furnishes sensitivity adequate for trace analysis when the signal is monitored at a carbon emission line. Work performed with one of th ese systems at high electronic gain for the carbon signal has revealed solvent band widths in excess of four minutes; these impeded quantifi cation of peaks eluting after the solvent. This report discusses two p henomena which could be related to the unexpected intensity of this so lvent response: photomultiplier tube saturation and carbon deposits in the quartz plasma discharge tube.