titrera

A titrera, in many Spanish-speaking contexts also called bureta, is a laboratory instrument used to dispense precise volumes of a titrant during a titration. It consists of a long, calibrated glass or plastic tube with a valve or stopcock at its lower end that allows controlled release of liquid. The device is designed to deliver accurate, reproducible volumes and is a standard tool in quantitative chemical analysis.

Construction and features: burettes commonly have a nominal capacity of 50 milliliters, though smaller 25 mL or larger sizes exist. The graduations are usually marked in 0.1 mL increments, allowing readings with fraction-of-a-milliliter precision when the meniscus is read correctly. The stopcock can be made of glass, PTFE, or other inert materials to minimize sticking and chemical reaction with the titrant. Materials are chosen for chemical resistance and optical clarity.

Operation: the titrant is filled into the burette and the tap is closed. After removing air bubbles and ensuring the initial volume is read at the bottom of the meniscus, the operator opens the stopcock gradually to deliver titrant into the reaction flask. The endpoint is reached when the analyte has completely reacted, as indicated by a color change, pH change, or an instrumental signal. The volume delivered is the final reading minus the initial reading.

Maintenance and accuracy: readings assume stable temperature, typically around 20°C, since volume changes with temperature. Burettes require thorough cleaning, proper storage, and occasional calibration to maintain accuracy. Reading accuracy depends on proper alignment, avoidance of parallax, and elimination of air bubbles.

Etymology and usage: the term titrera is the Spanish form of the device commonly called burette in English, used across chemistry laboratories for precise titration procedures.