Determination of critical micelle concentration and interactions between cephalosporins and charged surfactants

An automated capillary gas chromatographic system to measure ethylene emitted from biological materials is presented. The system consists of an on-line sampling device, a thermodesorption preconcentration apparatus and a capillary gas chromatograph with a flame ionization detection system. The limit of detection achievable on the GC system alone is 5 pg ethylene. The use of the strong Carboxen 1000 adsorbent at a sampling temperature as low as −50°C allows sampling of volumes up to a few liters. Ethylene concentrations at low ppt levels can be accurately and reproducibly determined.