Detection of gases using an organic semiconductor, anthracene.

A new type of detector has been designed and constructed on a basis of the fact that the adsorption of gases causes a change in electrical conductivity of organic semiconductors. This detector called the organic semiconductor detector (OSD) makes use of the surface cell of anthracene single crystal. The sensitivity of the cell was dependent on applied voltage, temperature, species of gases and concentration. The OSD has been applied to gas chromatography and the effectivity and selectivity of the detector for the detection of various gases have been examined. Acetone was chosen as the internal standard and arbitrarily assigned a signal response of “1.0” unit per mole and the relative response values of various compounds investigated are reported. The sensitivity of the detector is quite good for amines, acetic acid, formic acid, acetaldehyde and normal alcohols which contain more than four carbons. The relative response values for amines were about 200~400 and these compounds could be detected up to 5×10^-9 g/s. The reproducibility of the OSD was good for each gas and the effect of fatigue on the sensitivity of the detector has not been observed over a period of four months.