Calibration of MIcropipettes

 Calibration of MIcropipettes

1.0 PURPOSE   

      The purpose of the standard operating procedure is to provide guidelines for calibration of various range micropipettes

2.0 SCOPE  

      The scope of this standard operating procedure includes calibration of micropipettes.

3.0 RESPONSIBILITY

3.1 Q.A. Executive

3.2 Technical Manager

3.3 Q.A. Manager

4.0 REQUIREMENTS

4.1 Purified Water

4.2 Calibrated digital Balance

4.3 Micropipette with tips

4.4 Micropipette Manual

5.0   PROCEDURE

5.1    Performance Verification of a Micropipette

5.1.1 Micropipette performance is evaluated using Gravimetric method. In Gravimetric 

         Method desired volume of purified water is placed or dispensed from micropipette &

         checked in term of weight on calibrated digital balance. The desired volume is

         termed as Nominal volume.

5.1.2  Calculation is performed to convert the weight of water to volume or vice –versa.

5.1.3 If the volume measuring device is properly operated, then the nominal volume

         will be identical to the volume as calculated from the weight of the water.

5.2    Calibration Procedure

5.2.1 Label 5 centrifuge tubes, Weigh each of them.                                                         

5.2.2  Use Micropipette of any size whichever is required for calibration, pipette the lower volume of that micropipette & aspired into the centrifuge tubes with the single tip  .

5.2.3 Weigh each of the five tubes. By subtraction, determine the weight of water in each tube.

5.2.4  A calculation is performed to convert the weight of water to volume or vice –versa.

                                   W

                 V    =   --------------

                                   D                      

            Where       W = weight in mg

                              V =   Nominal Volume in micro litre

                              D   =   density of purified water in mg/micro litre

5.2.5   Calculate the standard deviation (repeatability) of micropipette based on these five weights.

5.2.6      Determine the closeness of average weight of purified water is to the expected Weight. Example If we are using 5┬ÁL micropipette, the average weight to be 5 mg.

5.2.7     Determine the accuracy of the micropipette by percentage error.

5.2.8     Repeat all the above steps with two mid ranges of the micropipette.

5.2.9     Repeat all the above steps with single upper range of the micropipette

CLASS RESULTS: MICROPIPETTORS

Sr.No

Volume

Precision
(expressed as Standard deviation)

Accuracy
(relative per cent)

Measured Accuracy as per Instrument Specification

Measured CV   %

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 5.3    Warning & Precautions                                                                                                                  

5.3.1      Never drop a micropipette.                                                                                            

5.3.2   Never rotate the volume adjuster of an the micropipette beyond the upper or lower range of the             Instrument.                                                                                                                  

5.3.3   Never pass a micropipette through a flame.   

5.3.4   Never use a micropipette without a tip thus allowing liquid to contaminate the shaft assembly.

5.3.5   Never lay a filled micropipette on its side thus allowing liquid to contaminate the shaft assembly.

5.3.6   Never immerse the barrel of a micropipette in liquid, only immerse the tip.

5.3.7   Never allow the plunger to snap up when liquid is being aspirated.

5.3.8   Store micropipette set to their highest volume. This releases pressure on the spring inside the               micropipette

6.0     REFERENCE   

6.1    The Biotechnology Project Laboratory Exercise 3 Measuring Volume. 

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