SOP - OPERATION AND CALIBRATION OF STANDARD ELECTRONIC BALANCE MODEL No: CP225D (MAKE: SARTORIUS)

1.0 Objective

To lay down a procedure for operation and calibration of CP225D analytical balance to give accurate and reproducible results.

2.0 SCOPE

This sop covers the operation and calibration procedure of analytical Balance and it is applicable to Quality control department.

3.0 Responsibility

Officer / Executive

4.0 Accountability

Department Head

5.0 Procedure

5.1 general cleaning PROCEDURE

5.1.1 Ensure that the power supply to the balance is switched ‘ OFF’ before cleaning

5.1.2 Clean the pan and inside of the balance with a brush.

5.1.3 Clean the outside of the balance with a clean dry cloth every day. occasionally wet cloth dipped in dilute soap solution maybe used .Precaution has to be taken to clean the balance immediately with dry cloth to remove the moisture.

5.2 Operating Instructions

5.2.1 Ensure that the balance is properly connected to power supply.

5.2.2 Check that the spirit level is in the center of the level or not and if necessary adjust the level by turning the leveling screws.

5.2.3 Switch on the main switch, this balance displays ‘±8,8,8,8,8,8,8,8,8,8,8,8’ followed by 0.00000 g (display unit is in gm)

5.3 WEIGHING PROCEDURE:

5.3.1 Place a clean butter paper on the pan, close the balance door and press at
“ TARE” position on the bar to tare the paper weight. The display should read 0.00000g.

5.3.2 With a clean spatula add required quantity of sample carefully on to the butter paper. Close the balance door.

5.3.3 Allow the balance to display ‘g’ along with the weight.

5.3.4 Carefully transfer the sample into the flask and place the butter paper again on the pan of the balance.

5.3.5 Record both initial and final readings.

5.4 PRECAUTIONS :

5.4.1 During the transferring of sample to the flask ensure that the neck of the flask, where the butter paper would be in contact is absolutely dry.

5.5 CALIBRATION

5.5.1 SELF CALIBRATION

5.5.1.1 Ensure that the power supply to the balance is switched ‘OFF’ before cleaning.

5.5.1.2 Clean the pan and inside of the balance with a brush.

5.5.1.3 Check that the spirit level is in the center of the level or not and if necessary adjust the level by turning the leveling screws and close the balance doors.

5.5.1.4 Switch on the balance and allow it to stabilize for 10 minutes.

5.5.1.5 Press the CAL button and display shows ‘C’ .After some times, the display shows as ‘CC’ and followed by 0.00000 g. which denotes the end of self calibration.

5.5.2 CALIBRATION AGAINST STANDARD WEIGHTS

5.5.2.1 Check the weight of the standard weights 100 mg, 200 mg, 500mg and 1g five times by keeping the weight on the ‘·’ positions on the Weight pan as shown in the figure.

5.1.1.1 Take 10 individual weights of 500 mg standard weight and note down the weights.

5.1.1.2 Calculate the Standard Deviation of the 10 individual weights and calculate the measurement of uncertainty by using the following formula.


= Standard Deviation x 3 .
Standard weight of 500 mg

5.1.1.3 Standard weight of 500 mg should be taken from the calibration certificate supplied along the weight box.

5.1.1.4 ACCEPTANCE CRITERIA

Tolerance shall not exceed 0.1% of the weight

5.1.2 ACCEPTANCE CRITERIA
The uncertainty measurement should not be more than 0.001


5.1.3 Record all the observations in the calibration record as per annexure-1.

5.1.4 Affix a ‘CALIBRATED’ label on the instrument.

5.1.5 Report any discrepancy observed during calibration or operating the instrument to department Head and notify the defect to Service engineer to rectify the defect. Affix “BREAK DOWN” label on the instrument till it gets rectified.

5.7 Frequency of calibration

Once a month and after each maintenance job.


6.0 REASON FOR REVIEW:

First time issue.