Desorption Device Research Articles

Desorptions- und eichvorrichtung zur spurenanalyse von organischen luftinhaltsstoffen mittels adsorptiver anreicherung und kapillar-gaschromatographie

For capillary gas chromatographic determination of organic air pollutants at ppb (10 9) levels being based on adsorptive sampling a desorption device were constructed permitting a substance trasfer from adsorption tubes to glass capillary columns. The gas chromatograph was additionally equipped with an arrangement of capillary columns which allows a controlled dosage of very small amounts of substances onto adsorption tubes with respect to identification and calibration. The performance of the technique reported was characterized by means of the reproductibility of the recoveries and retention data. On the basis of two air samples of different origin the practical applicability of the method was discussed.

Mise en evidence de l'influence de la temperature sur le gain d'un multiplicateur tubulaire d'electrons sans fenetre

The gain of twenty units of different channel electron multipliers are studied as a function of temperature for variable applied voltages and incident fluxes. The devices show an exponential reduction of gain when the temperature decreases dating from 50°C, upper limit of utilization. This reduction depends on the contamination of the layer and it is necessary to obtain accurate and stable characteristics to find a rapid desorption device of the inner channel surface. The interpretation of this law shows that the output current is proportional to the conduction layer current.