Selective Detector for Gas Chromatography Based on Adduct-Modulated Semiconductor Photoluminescence

摘要

The photoluminescence (PL) of semiconducting n-CdS, Te-doped CdS, and CdSe can be used as the basis for a non destructive, selective detector for gas chromatography. When placed in a series with the thermal conductivity detector (TCD) of a gas chromatograph, the semiconductor responds in parallel with the TCD to species that can engage in adduct formation: PL intensity is enhanced by Lewis bases like amines and quenched by Lewis acids such as carboxylic acids, relative to the intensity observed in the He carrier gas. Gases that interact more weakly with the semiconductor surface like hydrocarbons are not detected by the PL-based detector. For a n-CdS:Te detector, linear response regimes and detection limits have been determined as being approx. 0.1-3.0 micro-g and o.1 micro-g for n-butylamine and approx. 0.2-1.5 mg and 0.2 mg for acetic acid. Keywords: Detectors; Gas chromatography; Semiconductors; Photoluminescence; Amines; Carboxylic acids; Tellurium; Cadmium sulfides; Selenides. (MJM)