Burettes
Burettes
Used to dispense and measure a variable amount of a chemical solution in analytical chemistry at the same time, burettes feature a long, graduated glass tube with a stopcock on its lower end for liquid measurement. The stopcock valve is used to control the flow of liquid from the burette in either a steady stream or drop-by-drop. Unlike a pipette, the sample quantity delivered by a burette is changeable. For gas measuring burettes, the stopcock is located at the top of the burette’s glass tube. Digital burettes that deliver exactly measured samples, increasing accuracy and precision, are also available.
Titrations are performed to determine the concentration of a specific substance by adding another substance that interacts with the first to neutralize it or to form another compound. Liquid is slowly dispensed from a burette into a flask or beaker that holds a known amount of the test substance. The burette has a solid glass or PTFE stopcock or other fitting to regulate the flow of the liquid.
The “unknown” substance is mixed constantly (via magnetic stirrer/stir bar or similar method) to ensure that the reaction is complete. Often, the end-point of the reaction is a specific change in the acidity or pH of the liquid; a chemical indicator may be used to produce a color change when the reaction is complete.
Burettes may be designed for single or multiple uses; replacement stopcocks, glassware, and other parts are available for most reusable versions.
Other burette features include:
- Material: Glass or plastic
- Size: Usually from 10 mL to 50 mL capacities
- Graduations: Choice of precision (0.01 or 0.1 mL)
- Certification: Class A or Class B, serialized and non-serialized
- Construction: Single-use or with replacement parts
- Types: Standard or self-filling/automatic
- Burets with PTFE-plug stopcocks
- Break-resistant, self-zeroing automatic burets
- Reservoir fill burets
Borosilicate Glass Class B Burette with Stopcock
Manufactured from borosilicate glass and omplies with BS-ISO 385 standards. Fisherbrand™ Borosilicate Glass Class B Burette with Stopcock includes single bore, interchangeable glass or PTFE stopcock with 0.10mL blue ceramic graduations.
Pyrex™ Labware Class AS Borosilicate Glass Burette
Manufactured from precision-bore tubing (borosilicate glass) for high accuracy and complies with ISO 385 standards. Pyrex™ Labware Class AS Borosilicate Glass Burette includes grease-free interchangeable PTFE key with 1.5mm bore. Graduations in white enamel provide increased visibility with dark solutions.
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Fisherbrand™ Borosilicate Glass Class AS Burette with Teflon Tap
Complies with BS-IS 385 standards. Fisherbrand™ Borosilicate Glass Class AS Burette with Teflon Tap includes single bore with interchangeable PTFE stopcock. Blue ceramic graduations make volume assessment easy.
Pyrex™ Labware Class AS Borosilicate Glass Burette Works Certified
Manufactured from precision-bore borosilicate glass tubing for high accuracy. Pyrex™ Labware Class AS Borosilicate Glass Burette Works Certified is individually tested and supplied with certificate showing exact volume dispensed at three points on the scale. Includes 1.5mm bore PTFE key which requires no lubrication.
Thermo Scientific™ Nalgene™ Acrylic Burets with PMP Tip, TFE Stopcock and Plug
Accurately perform applications with these acrylic burets with PMP tip, TFE stopcock and plug, which meet ASTM E287 standards.
Thermo Scientific™ Nalgene™ Break-Resistant Self-Zeroing Automatic Burets
Ensure repeatable, accurate results with these break-resistant, self-zeroing, automatic burets which meet ASTM E287.
Pyrex™ Labware Class AS Borosilicate Glass Schellbach Burette with PTFE Key
Manufactured from chemically resistant borosilicate glass and complies with ISO 385 standards. Pyrex™ Labware Class AS Borosilicate Glass Schellbach Burette with Glass Key features a vertical white stripe and central blue ribbon to facilitate accurate reading of the meniscus. Funnel top makes filling easier and safer. Includes grease-free interchangeable PTFE key with 1.5mm bore.
BRAND™ BLAUBRAND™ Borosilicate Glass Compact Burettes
Fast to dismantle and easy to clean. BRAND™ Blaubrand™ Borosilicate Glass Compact Burettes are also simple to repair because all individual components replaceable.
Pyrex™ Labware Class B Borosilicate Glass Burette with PTFE Key
Manufactured from chemically resistant borosilicate glass and complies with ISO 385 standards. Pyrex™ Labware Class B Borosilicate Glass Burette with PTFE Key includes white enamel graduations for good visibility with dark colored solutions.
BRAND™ BLAUBRAND™ Borosilicate Burettes with Lateral PTFE Stopcock
Constructed from borosilicate glass. BRAND™ Blaubrand™ Borosilicate Burettes with Lateral PTFE Stopcock are calibrated to deliver contents that correspond to a volume as specified.
BRAND™ SILBERBRAND Compact Automatic Burette with Schellbach Stripe
Compact Automatic Burette designed to be fast to dismantle and easy to clean.
BRAND™ BLAUBRAND™ Borosilicate Burette with Straight Stopcock
Borosilicate glass construcion. Calibrated to deliver (TD, Ex). Supplied with batch number and enclosed one batch certificate per packing unit of the manufacturer.
BRAND™ SILBERBRAND Compact Burette with Schellbach Stripe
Compact Burette designed to be fast to dismantle and easy to clean.