Why is the pipet more accurate
Checking Pipette’s Accuracy and Precision
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the mechanical pipette which is almost
the most important device inside any
laboratory procedure that deals with
liquid transfer the mechanical pipette
is used to transfer small volumes of
liquids
since laboratory procedures usually
involve small liquid volumes the pipette
has to be accurate
therefore a procedure to ensure the
accuracy of the perpetual is a must in
order to make sure that your pipette is
actually drawing and dispensing the
right volumes for accurate and reliable
results there are multiple methods to
check your pipette accuracy but in our
laboratory we follow the gravimetric
method provided by ISO
you
before you start determine the z factor
the Z factor is determined by measuring
the temperature and the atmospheric
pressure
they use the table provided by ISO to
locate the Z factor that matches your
temperature and atmospheric pressure
the Z factor is one point zero zero
three four because the temperature of
our laboratory is 23 degrees Celsius and
the atmospheric pressure is ninety five
Cola tasko
now we can start
put the flask on the balance
note it is recommended to have water in
the flask prior starting the procedure
blanket to prevent your flasks weight
from interfering with your measurements
put on a tip suitable to pipette to be
calibrated
it is recommended to draw and dispense
multiple times to wet the tip before
using it then
draw a 100
percent of Pripet samin volume then
dispense it in the flask to measure its
weight
record the weight on your notebook
repeat the same procedure 9 more times
you
after 10 measurements repeat the same
procedure with 50 percent and 10 percent
of the maximum volume multiply each
single measurement by the Z factor to
correct your measurements these are our
measurements multiplied by the z factor
calculate a systemic and random errors
using the corrected measurements again
these are our results and these are the
calculations for each volume
obtain the maximum permissible error
from ISO 8655 protocol
our pipette is good to go since all of
the results are below the maximum
permissible error
you
