Burets used by students for classical titrations may be purchased with three interconnecting components: the main glass stem, a stopcock, and a replaceable glass capillary tip. The replaceable tip makes the three-component buret more attractive than the unibody-constructed buret, which may become permanently inoperable if the capillary tip becomes clogged. Ironically, replacement of these tips may be quite challenging because of variations in the external diameter of the replacement tips. These variations are frequently the cause of leaks, which prevent the buret from being used effectively. In many cases, the application of silicone grease is inadequate in correcting leaks. As a remedy for buret leaks caused by an improper tip-to-stopcock fit, Teflon tape (1.2 cm in width) should be wrapped tightly around the glass tip before its insertion into the stopcock. This tape will fill voids as the glass tip is pushed up while twisting into the stopcock, providing the seal needed where silicone grease failed.
More Information
Citation
Boshco, Brett C.; Griffin, John J. J. Chem. Educ.2000 77 1342.
Keywords
General Chemistry; Introductory / High School Chemistry; Analytical Chemistry; Laboratory Equipment / Apparatus
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