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 5µL
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.