Large-bore coated columns for sampling and concentration of organic volatiles in air, headspace and water analysis.

Large-bore coated (LBC) columns were used as sampling and concentrating traps in analyses for traces of organic volatiles in air and water. This simple technique utilizes long metal columns thinly coated with SE-30 for direct trapping of the organics. The sample is simply passed through the LBC column; the trapped organics are then thermally desorbed onto a conventional porous polymer pre-column or onto a second LBC column. If desired, this can be shorter or narrower bore than the initial LBC sampling column. The sample is finally desorbed onto the gas chromatographic column for analysis. Multiple transfers between LBC columns are possible, with increased concentration at each transfer, resulting in a "concentration pump" effect. The technique offers the advantages of great simplicity, efficiency and ease of sample transfer. Samples are obtained with low back-pressure and minimal interfering artifacts. The system shows almost complete imperturbability to moisture. Indifference to moisture and the low back-pressure enable direct sampling of very large volumes of air and even breath. Direct sampling of aqueous systems was also possible. The latter area was not fully investigated but offers potential for water pollution analysis and in direct examination of biological fluids and aqueous flavor extracts where heat sensitivity is a problem. With LBC columns the sampling and concentration sequence exposes the substances sought to no more drastic conditions than those they will be subjected to in the process of gas chromatographic analysis.