SOP for operation and calibration of micropipettes.

This article describes about  Operation and calibration of Micropipettes using in Quality control microbiology department of pharmaceutical industry.

SOP for operation and calibration of micropipettes.

OBJECTIVE :

To lay down the procedure for operation and calibration of micropipettes.

SCOPE :

This procedure is applicable for operation and calibration of micropipettes.

RESPONSIBILITY :

• Department officer and executive shall be responsible to follow the procedure of operation and calibration of micropipettes as per SOP.
• Section head shall be responsible for the checking and compliance of procedure as per SOP operation and calibration of micropipettes

ACCOUNTABILITY :

• Department Head
• Head Quality / QA

PROCEDURE FOR OPERATION AND CALIBRATION OF MICROPIPETTES : 

Operation of Micropipette :

• Sterilize the tips of micropipette in autoclave for validated time & temperature.
• Before use adjust the micropipette (if Variable) to the required volume by rotating the volume setting button.
• Attach sterilized tip below the ejector shaft to micropipette without touching by hand.
• Press the operating button to the first step with thumb.
• Immerse the pipette tip approximately 1 cm and allow the control button to slide back slowly. Wait for a while & then withdraw tip touching it against the edge of the reservoir to remove excess liquid adhering to outer surface of the tip.
• Dispense the liquid into the receiving vessel by gently pressing the operating button to the first stop & wait until the liquid stops flowing.
• Press down the control button to the second stroke until the tip is completely empty.
• Remove the pipette from the vessel sliding up the wall of the vessel.
• After completion of the operation press eject button to remove the micro tip.
• Every time use new tip for sucking the liquid.
• Wipe the micropipette with 70 % IPA before and after every use. If micropipette is autoclavable then sterilize the pipette for validated time & temperature.
• In case if any discrepancy is observed during operation inform to Manager-Quality Control and use another micropipette (stand by) available in Microbiology Lab.
• Remove the pipette from the vessel sliding up the wall of the vessel.
• After completion of the operation press eject button to remove the micro tip.
• Every time use new tip for sucking the liquid.
• Wipe the micropipette with 70 % IPA before and after every use. If micropipette is autoclavable then sterilize the pipette for validated time & temperature.
• In case if any discrepancy is observed during operation inform to Manager-Quality Control and use another micropipette (stand by) available in Microbiology Lab.

Calibration :

• Analytical balance use in calibration should be calibrated.
• Purified water with temperature 20°C to 25°C shall be use as test liquid.

For 50 µl -200 µl micropipette :

• Place a dry weighing bottle on the balance pan and tare the balance.
• Set micropipette at 50 µl and pipette 50µl of water.
• Dispense 50 µl of water in the weighing bottle and record the weight.
• Perform the above activity thrice by taking the same quantity of water.
• Perform the above activities again by setting the micro pipette at 50µl, 100µl.
• Average the three reading of weights and calculate the volume by the formula mention in section 01

For 100 µl -1000 µl micropipette :

• Place a dry weighing bottle on the balance pan and tare the balance.
• Set micropipette at 100 µl and pipette 100µl of water.
• Dispense 100 µl of water in the weighing bottle and record the weight.
• Perform the above activity thrice by taking the same quantity of water.
• Perform the above activities again by setting the micro pipette at 500µl, 1000µl.
• Average the three reading of weights and calculate the volume by the formula mention in section 01

For 1000 µl -10,000 µl micropipette :

• Place a dry weighing bottle on the balance pan and tare the balance.
• Set micropipette at 1000 µl and pipette 1000 µl of water.
• Dispense 1000 µl of water in the weighing bottle and record the weight.
• Perform the above activity thrice by taking the same quantity of water.
• Perform the above activities again by setting the micro pipette at 5,000 µl, 10,000 µl.
• Average the three reading of weights and calculate the volume by the formula mention in section 01

1) Calculate the volume of water by the formula : V = M (Mass) / D (Density) X 1000

Where, Density of water (g/mL) versus Temperature (°C) is mention in Table-1. (To convert milliliter (ml) in micro liter multiply by 1000).

Note: Whole degrees are listed down the left hand side of the table, while tenths of a degree are listed across the top.

For example, to find the density of water at 20.5° C first find the whole degree by searching down the left hand column until reach 20. Then slide across that row until reach the column labeled ‘0.5’. The density of water at 20.5 °C is 0.998099 g/mL.

Table-I

Accuracy :

Perform the Accuracy of the pipette by following procedure

Accuracy is the difference between the dispensed volume and the selected volume of a pipette.

A = V_{o –} V

Where,    A = Accuracy, V = Mean volume, Vo = Nominal volume

Accuracy can be expressed as a relative value: A% = 100 x A/V_o

                                                                TABLE-2

REFERENCES USED FOR PREPARATION OF SOP OPERATION AND CALIBRATION OF MICROPIPETTES :

In-house /ISO 8655/ pipette manual