Bürette

A Bürette, in English burette, is a precision glass instrument used in chemical titrations to dispense measured volumes of a liquid, typically a titrant, into a reaction vessel. It enables accurate determination of the amount of titrant required to react with a given analyte, supporting concentration calculations.

A burette consists of a long, narrow glass tube with a calibrated scale and a stopcock at the bottom. Common practical capacities are 0–50 mL or 0–100 mL. The graduations may be 0.1 mL or finer, with readings commonly taken to 0.01–0.02 mL in high-precision work. The stopcock is usually made of glass or PTFE and controls the flow of liquid. The tube is mounted vertically in a burette clamp during use, and the tip is tapered to permit steady, controlled drainage.

Calibration and procedure involve several steps. The burette is rinsed with the titrant to be used and filled with this solution, ensuring no air bubbles remain. It is then filled above the zero mark and brought to the zero point. Readings are taken at eye level from the bottom of the meniscus. The volume delivered during a titration equals the final reading minus the initial reading. Proper technique minimizes parallax error and ensures consistent flow by adjusting the stopcock gradually.

Maintenance and handling require careful cleaning after use, typically with appropriate solvents, and thorough rinsing to remove residues. The instrument should be stored upright with the stopcock closed to prevent leaks. Bürettes are standard laboratory equipment for quantitative analysis and remain a fundamental tool in acid–base, redox, and complexometric titrations.