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column was conditioned at 250°C, and the capacity ratio for acetone, diethyl ether, 1,2-dichloroethene, and n-hexane were measured after 64 and 500 hours conditioning at this temperature. The results are given in Table 3. Table it is clear to see that the capacity ratio remains almost unchanged after continuous use at 250OC. The dk/dt value forn-hexane is 0.001 15 h-', which results in an estimated life time of 380 days according to [12]. Therefore the column can be conditioned for more than a year at 25OoC, during which a capacity decrease of 50% is found. From this ConclusionThe coating of a porous polymer onto fused silica capillary columns combines the unique retention characteristics of porous polymers with high resolution capillary gas chromatography. The use of adsorption chromatography for the separation of results in analyses temperatures which are above ambient and therefore easy to control. Analysis of oxygenated gases, like CO and C02, is possible without significant tailing. The strong hydrophobic character of the PoraPLOT Q porous polymer makes the determination of water at ppm level possible.PoraPLOT Q columns can be used up to 25OOC without deterioration of the adsorbent. The unique selectivity and retention makes the PoraPLOT Q column a powerful tool in the separation of permanent gases and the column will also find an application as a substitute for many capillary columns in gas liquid chromatography. References [l][2]J.

Summarydifficult to prepare capillaries for adsorption chromatography or to increase the surface area andlor energy by roughening the surface.A method has been developed for fabricating fused silica capillary columns which have specificsurface properties but still retain the excellent strength, flexibility, and resilience of pure fused silica. By using the Modified Chemical Vapor Deposition process (MCVD), typicallyusedfortheproductionof optical fiber lightguides, inorganic dopants such as Al, Nd, Ge, and P can be introduced into the preform-tube by MCVD. Doped columns have a wide range of specific surface properties, and columns with undoped fused silica prepared by MCVD are more chemically inert and less acidic than columns prepared by conventional methods. This paper describes the method for fabricating capillaries and the initial studies to characterize them.

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