Annular denuder tube preconcentrator for nitrobenzene determination by gas chromatography with electron-capture detection

A platinum/lead alloy-coated annular denuder tube was employed to concentrate nitrobenzene from nitrogen atmospheres of relative humidity < 5% at ambient temperatures. The limit of detection achieved was 1.7 ng of nitrobenzene, which could be obtained from a concentration of 0.15 μg m^?3 of nitrobenzene in nitrogen. Quantification was carried out at concentrations above 0.12 μg m^?3 of nitrobenzene in nitrogen over a 4-month period, although ageing and deterioration of the denuder system were noted, necessitating regular recalibration. The results support claims made elsewhere regarding the suitability of denuder tubes for organic vapour determination, in this instance with an analyte-selective collection surface.