Burette

A burette (also buret) is a device used in analytical chemistry for the dispensing of variable, measured amounts of a chemical solution. A volumetric burette delivers measured volumes of liquid. Piston burettes are similar to syringes, but with precision bore and plunger. Piston burettes may be manually operated or may be motorized. A weight burette delivers measured weights of liquid.

Uses

Overview

A burette is distinguished from a pipette by the fact that the quantity delivered is variable. Thus in a titration, one solution is dispensed with a pipette, and another solution is added to it from a burette in aliquots of varying size.

Burettes may be designated for use at a particular temperature. If used at another temperature they should be subject to calibration.

Volumetric burettes

Analogue

A traditional burette consists of glass tube of constant bore with a graduation scale etched on it and a stopcock at the bottom. The barrel of the stopcock may be made of glass or the plastic PTFE. Stopcocks with glass barrels need to be lubricated with vaseline or a specialized grease. Burettes are manufactured to specified tolerances, designated as class A or B and this also is etched on the glass.