Analytical balances are highly sensitive weighing devices used to measure small masses in the sub-milligram range. They have an enclosed weighing pan inside a transparent draft shield to prevent dust and air currents from affecting measurements. Analytical balances must be calibrated regularly and located in areas free of vibration and electromagnetic interference to provide accurate readings. Proper weighing technique requires taring the balance, centering samples on the pan, and allowing readings to stabilize before recording results.

1. Analytical Weighing Balance
Md. Abdul Karim Mia
Analyst
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh

2. Balance
Balance: A weighing device, especially one consisting of a rigid beam horizontally
suspended by a low-friction support at its center, with identical weighing pans hung
at either end, one of which holds an unknown weight while the effective weight in
the other is increased by known amounts until the beam is level and motionless.
Analytical balance is a class of balance designed to measure small mass in the
sub-milligram range. The measuring pan of an analytical balance (0.1 mg or better)
is inside a transparent enclosure with doors so that dust does not collect and so any
air currents in the room do not affect the balance's operation. This enclosure is
often called a draft shield.
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh

3. History of Balance
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Simple Balance was used as early as 2400-
1800 B.C near Indus river valley ( Now
Pakistan)
Balance comes from the Latin word “ Lilanx”
means `Two pans`
The lightweight technique is developed
Joseph Black.
The modern analytical balance originated
during the mid-18th century

4. Types Of Balance
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Type- I
Type- II
Type- III
Light weighing capacity
and
Highly Sensitivity
Built-in weights for analytical
balances
and
Laboratory weights for routine
analytical weights
Precision Balances
and
all other weighing equipments
Semi Micro balance:
5 µg to 500mg
Micro balance:
2mg to 20 gm
Analytical balance
100 mg to 100 gm
Top Load balance
1.0 kg to 2.0 kg

5. Sartorius Analytical balance
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Weighing pan
Tare/Zero switch
Gram/g
Display
Level Indicator
CAL button
On/off switch
Adjustable feet
Windbreak door
Function Key
Calibration Tag

6. Where to locate analytical Balance
 Install the balance on a solid bench that is (AVT) anti vibration table.
 Doesn't locate AVT corner of the room-room access through a sliding door.
 The balance should not be installed near sources of electromagnetic
radiation such as radio frequency generators, electric motors, hand held
communication devices (including card less telephones and cell phones)
 humidity range 45 - 60% Operate. Humidity range <20 – 80<% Never operate
 Never disconnect the balance from the power supply and leave it always
switched on / STAND BY mode. If “OFF” mode: warm-up for 1 hour after
switching ‘ON’ the power supply.
Note: Stable anti vibration table-has affect on balance for measurement 0.01g or
less.
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh

7. Weighing Procedure of analytical Balance
 Ensure the instrument is clean and free from dust. If presence clean with soft
brush
 Check the adjustment bubble within the center and calibration tag within expiry
date.
 Ensure that daily calibration is done and check the log book.
 Place the weighing paper on the weighing pan, close the windbreak door and
press tare button to zero.
 Place the sample of standard or sample on the weighing pan using spatula and
close the windbreak door.
 Take the reading from display shows as gram after stabilized.
 Record the weighing results on log book.
 Carefully remove the weight and left clean for another analyst
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh

8. Calibration Parameters
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Minimum Weight/Repeatability: Repeatability is a measure of the ability of a balance to
supply the same result in repetitive weighing's with one and the some load under the
same measurement conditions. Measurements must be carried out by the same
operator, using the same weighing method, in the same location on the same pan
support, in the same installation location, under constant ambient conditions, and
without interruption.
Procedure:
1. Take measurement of 50 % or more load of the balance for 10 times.
2. Record the value and calculate as follow
Minimum weight: IF SD>0.41d Desired minimum weight = 2*SD*1000
IF SD<0.41d Desired minimum weight = 2*0.41d*1000=820d
Repeatability: 2*SD / Desired minimum sample weight Lt: ≤0.1%

9. Calibration Parameters
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Accuracy: Accuracy is defined as the proximity of measured results to the reference
value. Accuracy is the systematic error.
Procedure:
1. Determine the range of test weights that will be used to make sure their mass is
between 5-100% of the balance capacity.
2. Measure the test weight placing in center position on weighing pan.
3. Repeat the measurement for all weight previously determined in that range.
4. Record the value and compare within range or not.
Lt: Measured value does not deviate by more than 0.1% of the test weight value.

10. Calibration Parameters
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Accuracy and Precision
(i) Accuracy: refers to how close an answer is to the “true” value
Generally, don’t know “true” value
Accuracy is related to systematic error
(ii) Precision: refers to how the results of a single measurement compares from one trial to the
next
Reproducibility
Precision is related to random error
Low accuracy, low precision Low accuracy, high precision
High accuracy, low precision High accuracy, high precision

11. Calibration Parameters
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Linearity:
Linearity describes how well a balance can follows the linear relation between the load
and the displayed value. A characteristic weighing curve should be a straight line from
zero to the maximum load.
Non-linearity defines the limits within which a measured value can deviate (positively or
negatively) from the ideal linear curve.
Eccentricity (Corner Test):
Deviation of the measurement value through off-center (eccentric) loading. The corner
load increases with the weight of the load and its distance from the center of the pan
support.

12. Trouble shooting
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Display Cause Solution
No segments
appears in display
1. No AC power is available
2. The power supply is not plugged in
1. Check the AC power supply
2. Plug in the power supply
H The load exceeds the balance capacity Unload the balance
L or Err 54 1. Something is touching the weighing pan
2. CPA2P-F model: calibration/ adjustment
nor possible without cover
1. Move the object touching the
weighing pan
2. To calibrate/adjust position either
the standard pan (8g) or the filter
pan (5g) along with the cover(3g)
Err 01 Display overrun Change the configuration in operating
menu
Err 02 Calibration parameter not meet. Eg
-Balance not zeroed
- Load on weighing pan
Calibrate balance when zero is
displayed.
Err 10 Tare memory not allowed Press (tare)

13. Trouble shooting
National Control Laboratory (NCL), DGDA, Dhaka, Bangladesh
Display Cause Solution
Err 10 The tare key is blocked when there is data in
the second memory, only one tare function
can be used at a time
1. Press (CF) to clear the memory and
release the tare keys
Err 22 Weight id too light or when using the
application program, there is no sample on
the balance
Increase the weight on the balance
Err 30 1. Interface port for the printer output is
blocked
1. Reset the menu factory settings
Err 235 Connecting cable do not correctly plugged
in
Plug in the cable correctly

14. Thank You