A Convenient Break-Seal A break-seal of conventional design' consists of a fragile glass tip inside a glass tubing and a "hammer" far breaking the glass tip. The inconvenience in using breakseals of this kind has been experienced by many chemists. A break-seal of an alternative design is shown in the figure. I t consists of two parts, the reagent bulb (B, sealed a t one end (A)) and the receiver tube. These two parts mate with matehine male and female elass standard-taoer "ioints (C) . . (size . 12/18or 14/20). . . The male stand&-taper joint on thlreagent bulb extends to form a thin glass tubing that is to be broken at thenarrowing (E). The end (G)of the thin tubing is bent toone side. The end of the receiver tube is a female standard-taper joint. There is an indentation (F)on one side of the wall of the receiver tube. When the reagent bulb is rotated, the bent end of the thin glass tubing hits the indentation, this causes the thin glass tubing to break at the narrowing (E), and thecontent ofthereagent bulb isadmitted into the receiver tube. I f a volatile solvent is handled, it is useful to have a "grease trap" (D)just below the joint on the receiver tube so that the grease at the joint will not be thinned and washed into the receiver tube bv the vaoar of the solvent. Although n hreak-seal of this design is nor totally grease-free, it doer have several advantages w e r a hrenk-real of ronventi~maldesign. It ir more cmvenient to use, it can be made very compact in size, it can be used in any position, and the broken seal can be easily replaced after each use. A break-seal of this kind should he satisfactory for most applications that normally require such a device.
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Shrive,. D. F. "The Manipulation of Air-Sensitive Compounds": McCraw-Hill: New Yo*. 1969; p 77.
On-Kok Chang
Universily of California-Davis Davis. CA 95616
728
Journal of Chemical Education
