SOP for Operation and Calibration of Micro-pipettes

This document details the procedure for the operation and calibration of various variable range micropipettes. sop for cleaning operation and calibration of micropipette

It is the policy of Xyz Limited that a written procedure shall be followed for the Operation and Calibration of various variable ranges of Micropipettes and its use monitored in order to ensure smooth operation to obtain consistent and reproducible results and minimize downtime and meet regulatory requirements.

When:- This procedure is to be applied at the time of Operation and Calibration of various variable ranges of Micropipettes.

RESPONSIBILITY AND Accountability

Persons along with their responsibilities and accountability are given below:

To prepare the SOP:- Executive – Corporate Quality Assurance

To follow the SOP accordingly:- Trainee Analyst/ Jr. Analyst/ Analyst/ Sr. Analyst

Manager – Quality Assurance:- To ensure implementation of SOP

PROCEDURE

5.1 GENERAL INSTRUCTIONS

5.1.1    Micropipettes come in many sizes. The most commonly used micropipettes found in a lab are P-1, P-10, P-20, P-50, P-100, P-200, P-250, P-1000, P-5000The number refers to the maximum volume (measured in microliters) that can be transferred The Plunger button or the body of the micropipette is marked with the minimum and maximum volume range.

5.1.2  Micropipette functions by using a disposable plastic tip which is the only part of micropipette that actually comes in contact with the solution.

5.1.3  The tips come in various sizes and colors. Each size of micropipette uses a specific size tip.

5.2 PRECAUTIONS 

5.2.1    Avoid mishandling of micropipette.

5.2.2    Never rotate the volume adjuster of a micropipette beyond the upper or lower range because this will damage the micropipette.

5.2.3    Never pass a micropipette through flame/fuming chemicals or reagents.

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

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

5.2.6    Do not contaminate the barrel of a micropipette with the liquid, only immerse the tip.

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

5.2.8    After usage micropipette should be set to their highest volume as this releases pressure on the spring  inside the micropipette

5.2.9    Perform calibration by wearing gloves in hands.

5.3 OPERATION

5.3.1    Select the correct size micropipette and tips.

5.3.2    Dial the volume adjustment knob to set the proper volume in the digital volume indicator.

5.3.3    Place the tip tightly on the micropipette.

5.3.4    Hold the micropipette vertically over the solution and push the plunger down to the first stop.

5.3.5    Insert the tip into the solution.

5.3.6    Slowly release the plunger and note that the solution is drawn into the tip.

5.3.7    Look at the tip to be sure that you do not have bubbles in the tip. (if a bubble exists, expel the solution and try again.

5.3.8    Dispense the solution by touching the tip to the side of the target container. Slowly depress the plunger to the second stop. Before releasing the plunger, remove the tip from the target container.

5.3.9    Be sure the tip is empty, then use the tip ejector to dispose of the tip into an appropriate disposal container.

6.0  Calibration of micropipettes

6.0.1    Calibration Frequency: Half Yearly

6.1  Requirements

6.1.1    Purified Water

6.1.2    Calibrated Digital Balance

6.1.3    Micropipette with tips

6.2 Performance Verification of a Micropipette | Micropipette calibration frequency

6.2.1    Micropipette performance is evaluated using the Gravimetric method. In Gravimetric 

Method desired volume of purified water is placed or dispensed from the micropipette & checked in terms of weight on a calibrated digital balance. The desired volume is termed as  volume

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

6.2.3   If the volume measuring device is properly operated, then the volume will be identical to the volume as calculated from the weight of the water.

6.2.4    Take wt in mg for the micropipette 10 µl or below 10 µl.  For all other micropipettes take weight in gm.

6.2.3    Label 5 centrifuge tubes,

6.2.4    Mount a new pipette tip & pre-rinse once with water.

6.2.5    Put the 1.5ml microcentrifuge tube on the weighing balance.

6.2.6    Tare the balance.

6.2.7    Add the necessary volume of water using a micropipette in the microcentrifuge tube.

6.2.8    Record the weight

6.2.9    Repeat the procedure five times using five different tubes & record the weight in the calibration data sheet.

6.3.0    Calculate Average weight, Standard deviation & % CV.

6.3.1  Calculate the volume of water using the formula:

Micropipette calibration calculation

            V =  Wt / 0.99602

           Where V =  volume in µl or ml

          W = Avg.wt in mg or gm.

          0.99602 = density of water at 25˚ C

6.3.2Calculate the  percentage Accuracy (A %) using the formula :

               A%    =   V   -   V_SET  X 100

                                 V_SET       

Where Vset   =   set volume        

6.3.4    Above step should be followed at Low, Mid and High Point of Micropipette for e.g.if a 100 µl pipette is taken then calibration has to be performed at 10  µl  (Low), 50 µl (Mid) &100 µl ( High) points.

6.3.5    For a micropipette  10 µl or below only a high point should be considered for calibration.

6.3.6    Record the Calibration data on XYZ/CQA/SOP-076/FR-01 as Calibration Datasheet Appendix I 

7.0 GENERATION OF INSTRUMENT CALIBRATION NUMBER   

Generate the instrument calibration number on the calibration datasheet as INSCALXXYYZZZ where INS denotes instrument, CAL denotes calibration, XX denotes the year, YY denotes month and ZZZ denotes sequence number.

8.0 ABBREVIATION

XYZ                  Xyz Limited

SOP                 Standard Operating Procedure

QC                   Quality Control

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