1. Glassware Calibration
By : Abhilasha Pandey
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2. Basics Review and Calibration of Volumetric
Glassware
In order to avoid systematic errors and for making accurate
measurements in analytical procedures , each of these
instruments must be properly calibrated. And to reduce the
Random Errors inherent when using these instruments, their
proper use must be understood.
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3. Type of Glassware
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TC (To Contain)
The contained quality of
liquid corresponds exactly
to the capacity contained on
the instrument . Ex:
Volumetric Flasks
TD (To Deliver)
The delivered quality of
liquid corresponds exactly to
the capacity indicated on the
instrument, IN TD all volumes
are measured b/w an initial
and final readings. Ex: Bulb
Pipettes and Burettes.

4. • Calibrated weighing balance.
• Calibrated thermometer, accurate to 0.1 ⁰C
with calibration certificate and values
traceable to NIST.
• Pure distilled or deionized water.
• Stop watch.
• Glassware should be clean properly.
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Requirements of glassware calibration

5. ∗ Calibration procedure for Volumetric Flasks
a. Calibration Should be carried out at 25±2 ⁰C.
b. Tare the weigh balance.
c. Weigh the empty volumetric flask and record value in gm.
And note if this is Class-A or other device.
d. Fill the volumetric flask up to mark with distilled water ,
and re-weigh it.
e. Measure the temperature of the water used.
f. Repeat the process minimum five times.
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Calibration Procedure

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Calculation performed for volumetric
calibration
GLASSWARE CALIBRATION FORM
Volumetric Flask
Glassware ID: AAS/50VF/01
Volume/Volume
range(in mL): 50
Manufacturer: Brand Date of Calibration:25/04/2014
Temperature of
water: 24O
C Density of water at above temperature: 0.99732
Correction factor: +0.188
S.No.
Empty flask
Weight (gm)
Weight of
flask with water
(gm)
Weight of
water (gm)
Weight of water
with correction
factor at 27O
C (gm)
Volume
(Weight/Density)
(mL)
1 39.3942 88.9992 49.6050 49.8050 49.9388
2 39.3944 88.9985 49.6041 49.8041 49.9379
3 39.3949 88.9998 49.6049 49.8049 49.9387
4 39.3942 89.1005 49.7063 49.9063 50.0404
5 39.3948 88.9993 49.6045 49.8045 49.9383
Mean Volume
(mL)= 49.9588 Deviation from actual value 0.0412
Acceptance criteria for 50ml ± 0.0600
Accuracy (%)= (Observed mean volume)X100/Actual volume= 99.92%

7. UNCERTAINTY TYPE A
Uncertainty due to Repeatability (U1)
S.No. x x-xm (x-xm)^2
1 49.9388 -0.0200 0.00040080
2 49.9379 -0.0209 0.00043765
3 49.9387 -0.0201 0.00040481
4 50.0404 0.0816 0.00665530
5 49.9383 -0.0205 0.00042107
xm 49.96ml 0.00831963
Variance 0.00207991
SD 0.04560600
Std uncertainty 0.02039562 ml
Relattive std
uncertainity U1 0.00040825
UNCERTAINTY TYPE B
Uncertainty due to Mass (U2): Rectangular Distribution
Balance Uncertainity from Certificate [S.No.- B016026993]
Uncertainity of Balance as per calibration certificate
at 95% of confidence Level (k=2) +/-0.14 mg
Uncertainty due to balance (+/-)0.14/2 0.07mg
Relative Standard Uncertainity (Weight- 50.0g) 0.00001U2 (gm)
COMBINED UNCERTAINTY: (U1)^2+ (U2)^2
Relative combined uncertainity
SQUARE ROOT OF CU 0.00040831
Std combined uncertainity 0.02039
EXPANDED UNCERTAINTY: Std Combined Uncertainty x 2 = 0.0408
(Coverage Factor is 2 At 95% Confidence Level)
Volume 49.96 ± 0.04 ml
Uncertainty 0.0817 %
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8. ∗ Calibration procedure for Burette
a. Calibration Should be carried out at 25±2 ⁰C.
b. Use your cleaned 50mL burette. Note if this is a Class A or other
device. Fill the burette with water. Make sure the tip is free of
bubbles. Drain into a waste beaker until it is at, or just below, the
zero mark.
c. Allow 10-20 seconds for drainage. Make an initial reading to a
precision of at least 0.01 ml. Test for tightness of the stopcock by
allowing the burette to stand for 5 minutes and then re-reading the
volume. There should be no noticeable change in the reading.
d. Once the tightness of the stopcock is assured, refill the burette and
again drain into a waste until it is at, or just below, the zero mark.
e. Drain about 5 mL of water from the burette into a clean previously
weighed beaker and weigh the beaker , and read the burette.
f. Repeat the process five times for same volume .and repeat this
process for 15,25,45 ml also.
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GLASSWARE CALIBRATION FORM
Burette
Glassware ID: N69-BUR06 Volume/Volume range(in mL): 50
Temperature of water: 24O
C Density of water at above temperature: 0.99732
Set Volume (ml) Empty Weight
Gm W1
Weight of beaker with water (gm) W2
1 2 3 4 5
0.5 60.0218 60.5207 60.5117 60.5146 60.5155 60.5198
5 60.0218 64.9999 65.0004 64.9998 65.0001 65.0000
25 60.0218 84.8064 84.8104 84.8038 84.8058 84.8404
50 60.0218 109.7205 109.7232 109.7154 109.7432 109.8439

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Calculation performed for Burette
GLASSWARE CALIBRATION FORM
Burette
Glassware ID: N69-BUR06 Volume/Volume range(in mL): 50
Temperature of water: 24O
C Density of water at above temperature: 0.99732
Set Volume
(ml)
Correction factor W3
Weight of water with correction factor (gm) at 27O
C [W4= (W2 + W3],W2= wt of Beaker
with water-Wt of empty beaker
1 2 3 4 5
0.5 0.0023 0.5012 0.4922 0.4951 0.4960 0.5003
5 0.0226 5.0007 5.0012 5.0006 5.0009 5.0008
25 0.1130 24.8976 24.9016 24.8950 24.8970 24.9316
50 0.2260 49.9247 49.9274 49.9196 49.9474 50.0481

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S. no. Set Volume (ml) Volume of water (W= W4/Density)
1 2 3 4 5
Mean
Volume
%
Accuracy
1. 0.5 0.5025 0.4935 0.4964 0.4973 0.5016 0.4983 99.6591
2. 5 5.0141 5.0146 5.0146 5.0143 5.0142 5.0144 100.2880
3. 25 24.9645 24.9685 24.9619 24.9639 24.9986 24.9715 99.8859
4. 50 50.0589 50.0616 50.0537 50.0816 50.1826 50.0877 100.1753
Accuracy (%)=
(Observed mean
volume/Actual Volume)X100

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UNCERTAINTY TYPE A
Uncertainty due to Repeatability (U1)
S.No. x x-xm (x-xm)^2
1 50.05890 -0.02878 0.00082829
2 50.06160 -0.02608 0.00068017
3 50.05370 -0.03398 0.00115464
4 50.08160 -0.00608 0.00003697
5 50.18260 0.09492 0.00900981
xm 50.08768 ml 0.01170987 Sum of square of (x-xm)
Variance 0.00292747
SD 0.05410607
Std uncertainty 0.02419697 ml
Relative
std U1 0.00048309
UNCERTAINTY TYPE B
Uncertainty due to Mass (U2): Rectangular Distribution
Balance Uncertainity from Certificate [S.No.- B016026993]
Uncertainity of Balance as per calibration certificate
at 95% of confidence Level (k=2) +/-0.14mg
Uncertainty due to balance (+/-)0.14/2 0.07mg
Relative Standard Uncertainity ( 50.ml) 0.00001U2 (gm)
COMBINED UNCERTAINTY: (U1)^2+ (U2)^2
Relative combined SQUARE ROOT OF (U1)^2+ (U2)^2
0.00048
Standard Combined Uncertainity (RCU*M) 0.02420
EXPANDED UNCERTAINTY: Std Combined Uncertainty x 2
(Coverage Factor is 2 At 95% Confidence Level) 0.0484
Volume 50.08 0.05 ml
Uncertainty 0.0966 %

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