A Simple Glass Connector for Teflon Tubing Teflon tubing is a useful laboratory item because it is chemically inert and con .. s. venirntlv available in a broad range of s w s from elerrronir supply ~ ~ l e lLiquid ,T~PW szap~etatco chromatography is one of the malor applirntionn of thi5 tuhing. ILSchief disadvantage is thc lark "fa simple, convcnienr menns of mnk~ngrunnectims because of it+ uell. i . . for l s m ~on known characteristi& of cold-flow,slipperiness, and inertness to adhesives. Mechanical connectors are available, but they are cumbersome and expensive and, although useful, do not solve the problem of simple connection t o glassware. For the most durable connections, Teflon can be glued t o glass using epoxy-resin adhesive after ionizing the surface of the Teflon with a solution of sodium in anhydrous liquid ammonia. This treatment is inconvenient and somewhat hazardous, and the alternative of using a commercial preparation of an organic sodium solution is unreliable. The idea ofslipping Teflon tubing over a tapered glass piece, with a Tygon cover, has been described,' but it is impractical for small sizes of tubing and, more seriously, this design, with the Teflon over the glass, will come apart under pressure expansion. Specially designed tubing, with a heat-shrinkable outer cover and a fusible interior2 has the same fault and requires special tubing. We found that Teflan-to-elass tuhine" connections can be made verv easilv and are reliable for a varietv of laboratorv " rind instrument aoolications involvine low t o moderate oressure. For examole. a 2-mm o.d. tubine connection withstands
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the Teflon tubing to be used. A shallow taper is made in the bore of the glass tubing with a carbon reamer so the Teflon tubing can be pushed into the tapered section t o make a connection (see figure). These glass connections can be used t o interconnect lengths of Teflon tubing of the same or different sizes (by joining two sizes of glass tubing) or t o connect Teflon tubing toglass apparatus, and can be quickly pulled apart and reconnected. Although this scheme appears almost too simple, we have found it to be effective and reliable in several applications in chromatography and other pressurized liquid systems, and think i t would be of value to others. 'Krulfeld, M., J. CHEM. EDUC., 44 (5), 303 (1967). Vadd, E. C., J. CHEM. EDUC., 44 (a), 486 letter (1967). National Institutes of Health Bethesda, Maryland 20014
J o h n I. Peterson William R. Dehn
Volume 54. Number 9, September 1977 / 547
