Laboratory burettes: how can titrant be delivered accurately during titration?

Essential for volumetric analysis, the burette delivers a finely controlled volume of titrant for acid–base, redox or complexometric titrations. Whether in borosilicate glass Class A to ISO 385 with a Schellbach stripe, fitted with a PTFE stopcock for demanding chemistry, or in a digital bottle-top version to minimise parallax error and speed up series, it ensures repeatability and safety. Capacity, graduations, tolerance, chemical compatibility and purge ergonomics are the key criteria for selecting the tool suited to your method.

What are the different types of burettes and how to choose the right one?

There are three main families of burettes: graduated glass models (PTFE or glass stopcock), automatic burettes with an integrated reservoir for rapid filling, and digital bottle-top burettes mounted on a bottle. The first provide reliable direct reading (high-contrast Schellbach stripe) and excellent chemical compatibility. Automatic versions integrate a reservoir and a levelling device so you can run successive titrations without refilling. Digital burettes use a piston to dispense to 0.1 mL resolution, reducing parallax and splashes, with a recirculation valve to purge air.

Selection criteria: capacity (5–100 mL), Class A tolerance, stopcock type (inert PTFE, ground-glass requiring grease), graduation (0.01–0.1 mL), solvent compatibility, anti-drip tip, amber for light-sensitive solutions, and maintenance (easy disassembly, replaceable seals). Consider a microburette for low volumes, and an automatic burette if you run intensive series.

Type	Principle	Applications
Glass burette, PTFE stopcock	Class A graduation, purge via inert stopcock	Academic titrations, routine QC, aggressive solvents
Automatic burette with reservoir	Rapid refill, levelling, steady flow	Titration series, QC laboratories
Digital bottle-top burette	Piston and digital display, recirculation	GMP/GLP work, reduced reading errors
Microburette	Low volume, fine tip	Micro-titrations, trace analytical chemistry

In which fields is a burette used?

The burette is central to titration across many sectors. In environmental testing: hardness, alkalinity, chloride, COD (chemical oxygen demand)/permanganate index. In food and beverage: total acidity in wines, juices and dairy products. In pharmaceuticals: pharmacopoeial assays (Ph. Eur.), raw material checks. In cosmetics: neutralisation and preservative determination. In chemistry: redox, complexometry (EDTA), precipitation. In life sciences and education: lab practicals and method validation. Automatic and digital versions safeguard series runs and standardise results.

The different types of burettes available

Burette

Frequently asked questions about laboratory burettes

How to choose between Class A and B?
Class A provides a tighter tolerance (ISO 385) for traceable results. Class B is sufficient for teaching or preliminary tests.

Glass burette or digital bottle-top?
Graduated glass is economical and universal. A digital unit minimises parallax error, speeds up series work and reduces splashes.

Which stopcock should you prefer?
PTFE is inert and grease-free. A glass stopcock offers excellent sealing but requires suitable grease and regular maintenance.

How to avoid air bubbles?
Condition the burette with the titrant, purge the tip, tap the wall, and use the recirculation on a digital before reading zero.

Solvent compatibility: any precautions?
Check chemical resistance (borosilicate 3.3 glass, PTFE/PFA). Avoid solvents that swell seals. Prefer amber glass for photosensitive reagents.

Maintenance and metrological verification?
Rinse after use, disassemble and dry. Check the tolerance by weighing water at 20 °C and recalibrate/take out of service if there is an abnormal deviation.