burette

A burette (also buret) is a vertical cylindrical piece of laboratory glassware with a volumetric graduation on its full length and a precision tap, or stopcock, on the bottom. It is used to dispense known amounts of a liquid reagent in experiments for which such precision is necessary, such as a titration experiment. Burettes are extremely accurate - a 50 cm3 burette has a tolerance of 0.1 cm3 (class B) or 0.06 cm3 (class A).

Also used for buretting are buretting syringes. These are calibrated to Volumetric A grade tolerances which are equal to or better than the traditional burette tolerance. The graduated buretting tube is provided with a thumb operated piston and PTFE seal which slide within the tube in a positive displacement operation. This arrangement is provided to achieve improvements in reliability, by removing problems of bubble entrapment while filling, leaks and blockages in stopcock mechanisms.

burette