1. CALIBRATION OF
PIPETTE
LABORATORY EXPERIMENT NO. 1
ANALYTICAL CHEMISTRY
GROUP 1
2. CONTENT OF
THE PRESENTATION
I. INTRODUCTION
II. METHODOLOGY (ILLUSTRATED)
III. DATA AND RESUTS
TABULAR SET OF VALUES AND VARIABLES
DERRIVED FROM THE TRIALS HAD
*STANDARD DEVIATION
*MEAN
*RELATIVE STANDARD DEVIATION
IV. DISCUSSION
V. CONCLUSION
VI. REFERENCES
3. I. INTRODUCTION
In this course-Analytical Chemistry, precision
and accuracy are the fundamentals to gain
realistic findings, hence we must first secure
the measurement glass wares usually used in the
laboratory by checking its calibration.
Calibration is the operation that determines the
functional relationship between measured values
wherein there is the standard value and the unit
under test.
In this experiment, pipette is the measuring
device being calibrated.
4. II. OBJECTIVES
To forecast good precision and
accuracy of the pipette.
To demonstrate proper usage of
pipette.
To identify instrumental errors
during the calibration.
To calculate and detect error by
formulating solutions.
5. WHAT IS A PIPETTE?
A pipette is used for
measuring small volume
directly from the reagent
bottle.
7. Then, do the 3rd
and 4th
procedure
continuously
until you arrived
at 10th trial.
8. IV. DATA AND RESULTS
WEIGHT OF THE LIQUID IN PIPETTE IN (ML)
MEASUREME WEIG TRIALS MASS OF gram of V= M/D
BEAKER WITH
NT HT H2o IN (g)
H2O (ml)
g/OC X
WEIGHT OF 66.9 1 76.9 10.00 10.06ml
EMPTY BEAKER
WEIGHT OF 76.9 2 88.65 11.75 11.82ml
BEAKER + 10ml
H2O
WEIGHT OF THE 10 3 98.65 10.00 10.06ml
SAMPLE (H2O)
TEMPERATURE 30oC 4 108.40 9.75 9.80ml
DENSITY 0.995g 5 115.40 7.00 7.04ml
/ml
6 129.15 13.75 13.83ml
7 139.80 10.65 10.71ml
8 150.15 10.35 10.41ml
9 160.00 9.85 9.91ml
10 170.00 10.00 10.06ml
13. RANGE OF PRECISION AND ACCURACY
16
14
12
10
Series 1
8
Column1
Series 3
6
4
2
0
TRIAL 1-3 TRIAL 4-6 TRIAL 7-9 TRIAL 10
14. V. DISCUSSION
In this study we used to identify the
significance of calibration certainly in our
course-Analytical Chemistry which was the basic
foundation in our discipline.
Based on our further study, we do commit errors
commonly and this error was subdivided; the two
frequently commit are:
*INSTRUMENTAL ERROR
*PERSONAL ERROR
Thus, this two usual error must be lessen to
achieve precision and accuracy.
15. MEAN/AVERAGE/ X
X=10.47
X
10.06ml
WE THEREFORE GET 11.82ml
ABOVE THE EXACT 10.06ml
CALIBRATION SINCE 9.80ml
NEARLY AT FIRST TRIAL 7.04ml
WE DO GET HIGHER 13.83ml
CALIBRATION AND THE 10.71ml
FLOW OF THE TRIALS IS 10.41ml
NOT CONSTANT . 9.91ml
10.06ml
16. STANDARD DEVIATION
S= 1.69
THIS MEANS THAT THIS VALUE IS THE
VALUE THAT DENOTES TO HOW CLOSE THE
SET OF NUMBERS ARE.
THIS VALUE WAS INFLUENCED MOST OF
THE MASS GOT BEFORE CONVERTING IT TO
VOLUME BECAUSE ACCORDING TO OUR
OBSERVATION, THE TRIPLE BEAM BALANCE
HAS ALSO A DEFECT WHILE IN USE, AND
THIS WAS PRESENTED IN THE DIVERGING
SET OF NUMBERS
17. RELATIVE DEVIATION
%RSD=16.20%
RSD WAS DERIVED FROM DEVIDING THE
STANDARD DEVIATION TO THE MEAN THEN
MULTIPLY THE QUOTIENT TO 100 AS THE %
SIGNIFIES.
THIS VALUE WAS KNOWN TO BE THE
PERCENTAGE ERROR THAT YOU WILL
COMMIT WHENEVER YOU USED THE PIPETTE
THAT WAS CALIBRATE.
THIS PERCENT OF ERROR IS A “NO, NO, NO”
IF YOU DESIRE PRECISION AND ACCURACY.
18. OTHER SIGNIFICANT AND USUALLY
USED MEASURING GLASSWARES
BURETTE-like pipette is also significant in
measuring discharge or collected liquid as it has
a stopper for controlling it.
VOLUMETRIC AND ERLENMEYER FLASK-are
both use for measuring large quantity of liquid
thus they will also offer large error if its
calibration is not correct.
THERMOMETER-its calibration ranges from 0OC
to 100OC and it is very complex to solve some
analysis if it has a failure particularly as it will
present incorrect measurement. Such getting
the density, temperature play a role in providing
the solution, that’s why we need to assure those
cases.
