MICROPIPETTES -CLEANING, OPERATION AND CALIBRATION
To outline the procedure for Cleaning, Operation and calibration of micro pipettes.
SCOPE
This procedure for cleaning, Operation and calibration of micropipettes is applicable in microbiology section.
RESPONSIBILITY
Originating department shall be responsible:
To Cleaning, Operation and Calibration of Micropipettes as per SOP.
Head Quality Control /designee shall be responsible for:
To review new or revised SOP.
To maintain the controlled copies of SOPs at required location.
Head Quality-Assurance /designee shall be responsible for:
To approve new or revised SOP.
To ensure implementation of system as per defined SOP.
Plant Head shall be responsible for:
To approve new or revised SOP
To ensure the implementation of the defined system.
PROCEDURE:
SAFETY/PRECAUTION/EHS
Take care while sucking up or releasing the volume.
Always use dry & clean pipettes for analysis.
Always store pipettes in pipette case after use.
Avoid re-use of pipettes tips for critical operations.
Sterilize pipette tips by autoclaving them prior to use if require.
Discard the tips if it is used to transfer sample which are insoluble in water & sticky in nature.
CLEANING PROCEDURE
6.2.1 Clean the pipettes after use with mild detergent or dry cloth or mop with IPA or methanol & allow dry at room temperature.
6.2.2 Clean the tips by taking hot water in a beaker & sonicate for few (2-3) minutes, repeat this two to three times & finally rinse with methanol. Allow to dry at 55 to 60 degree. Celsius in an oven.
OPERATING PROCEDURE
Forward Pipetting:
Press the operating button to the first stop.
Dip the tip attached to the pipette into the solution to a depth of about 1 cm, and slowly release the operating button. Wait for a while, then withdraw it from the liquid touching it against the edge of the reservoir to remove excess liquid adhering to the outer surface of the tip.
Reverse Pipetting:
Press the operating button to second stop.
Dip the tip attached to the pipette into the solution to a depth of about 1 cm, and slowly release the operating button. This action will fill the tip with a volume that is larger than the set volume. Wait 1-2 seconds and withdraw the tip from the liquid, touching it against the edge of the reservoir to remove excess liquid.
Dispense the liquid into the receiving vessel by pressing the operating button gently and steadily to the first stop. This volume is equal to the set volume. Hold button in this position. Some liquid will remain in the tip, which should not be dispensed.
The liquid remaining in the tip can be dispensed back into the original solution by pressing the button to the second stop or disposed together with tip.
Volume setting:
Rotate the operating button clockwise to increase the set volume and anticlockwise to decrease the set volume.
CALIBRATION PROCEDURE
Equipment & Material required
Micropipettes.
Micro tips.
Calibrated balance.
Purified water
Perform at least three point calibration if micropipette used to pipette out variable volume The range of volume shall be selected within working range taking account of minimum, maximum & mid volume range as appropriate.
| Micropipette Volume range | Calibration Set Volume |
| 10 µl to 100 µl | 10 µl, 20 µl, 50 µl and 100 µl |
| 20 µl to 200 µl | 20 µl, 50 µl, 100 µl and 200 µl |
| 100 µl to 1000 µl | 100µl, 200 µl, 500 µl and 1000 µl |
| 1000 µl to 10000 µl | 1000 µl, 5000 µl and 10000 µl |
For all the variable volume pipettes calibrated as given below:
Take 100ml of Purified water in a clean beaker and stabilize the water to 25 ±10C. Take other dry beaker of suitable capacity and place it on a balance note its weight let it be (A) now take 100µl volume through suitable pipette and dispense it in previously weighted beaker repeat the same procedure total ten times and note the total weight with beaker let it be (B) and calculate the weight of set volume by formula: = (B-A)/10. Take all the weights in mg. Repeat the same procedure for other volumes and pipette.
Acceptance Criteria: The micropipette shall be deemed fit if the pipetted volume lie as per
| Set Volume | Minimum (mg) | Maximum (mg) | Limit | ||
| 10 µl | 9.7706 | 9.78 | 10.1694 | 10.17 | (Nominal Volume x 0.997) ± 2 % |
| 20 µl | 19.5412 | 19.55 | 20.3388 | 20.34 | (Nominal Volume x 0.997) ± 2 % |
| 50 µl | 48.853 | 48.88 | 50.8470 | 50.85 | (Nominal Volume x 0.997) ± 2 % |
| 100 µl | 97.706 | 97.70 | 101.6940 | 101.70 | (Nominal Volume x 0.997) ± 2 % |
| 200 µl | 197.406 | 197.40 | 201.394 | 201.40 | (Nominal Volume x 0.997) ± 1 % |
| 500 µl | 493.515 | 493.51 | 503.485 | 503.48 | (Nominal Volume x 0.997) ± 1 % |
| 1000 µl | 991.018 | 991.01 | 1002.982 | 1002.99 | (Nominal Volume x 0.997) ± 0.6 % |
| 5000 µl | 4955.09 | 4955.09 | 5014.91 | 5014.91 | (Nominal Volume x 0.997) ± 0.6 % |
| 10000 µl | 9910.18 | 9910.18 | 10029.82 | 10029.82 | (Nominal Volume x 0.997) ± 0.6 % |
Add calibration tag to the equipment or out of order if equipment does not meet with the acceptance criteria.
If the equipment does not meet the calibration criterion fix the out of Calibration tag on it and inform Quality Control head.
Frequency of calibration
Quarterly.
