Class B One Way, Glass Key Stopcock
Class B One Way, PTFE Key Stopcock
Class B One Way, All PTFE Key Stopcock
Class B Two Way, Glass Key Stopcock
Class B Two Way, PTFE Key Stopcock
Class B Pinch Clip Type
Dispensing, One Way, Glass Key Stopcock
Class A One Way, Glass Key Stopcock
Class A One Way, PTFE Key Stopcock
Class A One Way, All PTFE Key Stopcock
Class A Two Way, Glass Key Stopcock
Class A Two Way, PTFE Key Stopcock
Burettes are used for titrations: a known quantity of substrate is measured into a flask, and the titrant is added slowly from the burette until the end point is reached and the volume is recorded. An indicator is often used to make the end point visible. There are many different types of titration, but they are usually either acid-base or redox reactions.
Burettes are always used quantitively. The class used will determine the accuracy and traceability of the burette.. All our burettes including Class B are now made with precision bore glass for improved accuracy along the entire scale length.
Class B burettes should be used when accuracy of 0.2% is sufficient in uncontrolled environments.
Class A burettes are used when an accuracy of up to 0.1% is required and in controlled environments.
Class A burettes are calibrated to half the tolerance of Class B burettes and each has a unique serial number for traceability. A certificate of accuracy traceable to national standards can be provided if required.
Types of Stopcock
Pinch clip burettes are an older and simpler design mainly used in education.
Glass key stopcocks are the traditional type and are prefered by some technitians because of the smooth action, greater control and longer life than PTFE key stopcocks.
PTFE key stopcocks are now the most frequently used because they do not need any lubrication and are less likely to jam than glass stopcocks.
All PTFE key stopcocks are made entirely of PTFE and are particularly suitable for schools as they are much less delicate than the other types and all of the parts are replacable separately.
Two Way burette stopcocks have a tap with an extra side arm for adding solution from a reservoir without the need of filling from the top with a funnel. Used in situations where a large number of titrations are required or when hazadous solutions are being used. See Automatic Burettes.