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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.
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.
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