PROPER PIPETTING TECHNIQUE Flashcards
are instruments used to measure
liquid ranging between volumes
of 0.2-10000ul and transfer it
from one sample container to
another.
Micropipettes or pipettes
Micropipettes or pipettes are
instruments used to measure
liquid ranging between volumes
of______ and transfer it
from one sample container to
another.
0.2-10000ul
• This is a basic liquid-handling
instrument for almost all
scientific laboratories.
Micropipette
• Mastery of their principles is key
to effective scientific research
and analysis.
MICROPIPETTES
• They are crucial in lab settings
like molecular biology and
diagnostics, precisely transferring
tiny liquid volumes.
MICROPIPETTES
Types of Micropipettes:
Micropipettes can be categorized based on their design and functionality:
Number of Channels
Volume Adjustment
Operating Mechanism
2 types of number of channels
Single-channel
Multi-channel
Has 1 channel to aspirate and dispense
liquid, allowing handling of one sample at a time.
Single-channel
Can handle 8, 12, or 16 samples
simultaneously by attaching multiple tips.
Ideal for high-throughput labs.
Multi-channel
Multi-channel
Can handle_______ samples
simultaneously by attaching multiple tips.
Ideal for high-throughput labs.
8, 12, or 16
2 types of volume adjustment Micropipette
Fixed volume
Variable volume
Aspirates and dispenses a fixed volume
without adjustment;
Fixed Volume
provides consistent and accurate results for repetitive pipetting.
Fixed volume
often includes a volume lock feature for
enhanced accuracy and safety.
Variable Volume
Allows users to manually adjust the
volume within a given range;
Variable Volume
2 types of operation mechanisms
Mechanical
Electronic or digital
Standard piston-driven pipettes where users manually set the volume and apply thumb pressure to operate.
Mechanical
Features digital controls and programmability to reduce human error,
with an electronic display;
Electronic
ideal for high-throughput labs requiring reproducibility.
Electronic
Components of MICROPIPPETE
Plunger
Tip ejector
Volume adjustment dial
Volume display
Shaft
Disposable tip
Piston
Friction ring
Springs
O-ring
: autoclavable attachments for
the uptake and dispensing of liquids using a pipette.
• Disposable Pipette Tip
: Holds the pipette tip in place.
• Shaft
: Shows the set volume.
• Volume Display
: Sets the desired volume.
• Volume Adjustment Dial
: Removes the disposable pipette tip.
• Tip Ejector
: Controls liquid aspiration and dispensing.
• Plunger
• are a consumable product that are purchased separately from a pipette.
It is important to use the proper type of tip as your pipette may not work correctly without it.
Disposable Pipette Tip:
The internal parts of a micropipette:
Piston
Friction ring
O-ring
Springs
Ensures a tight seal to prevent air or liquid leakage, crucial for precision.
• O-ring:
Provide the necessary tension for the piston to return to its original position after dispensing.
• Springs:
Helps regulate the smooth motion of the
piston.
• Friction Ring:
Drives the liquid aspiration and dispensing process.
• Piston:
Common pipette sizes
P2
P10
P20
P100
P200
P1000
Common Micropipette Sizes
Volume Range???
P2
P10
P20
0.2-2 uL
1-10 uL
2-20 uL
P100
P200
P1000
20-100 uL
20-200 uL
100-1000 uL
How does a Micropipette work?
Micropipettes operate on the principle of_______
air displacement
The volume of air displaced corresponds to the selected aspiration volume.
Air Displacement Pipette
Plastic tip contains an integrated piston.
Positive Displacement Pipette
Micropipettes operate on the principle of air displacement.
They consist of a plunger connected to an internal piston, which moves
to two distinct positions:
• Filling position
• Dispensing position
______ position
• When the plunger is depressed
to the first stop, the internal
piston displaces a volume of air
(air displacement) equal to the
desired volume shown on the
volume indicator dial.
• This air displacement creates a
vacuum inside the pipette tip,
allowing liquid to be drawn up
when the plunger is slowly
released while the tip is
submerged in the liquid.
Filling position
________ position
• The second stop on the plunger is used solely for ______ the contents of the tip.
• Pushing the plunger to the second stop forces a burst of air through the tip,
ensuring that all liquid, including any residue, is fully expelled.
Dispensing position
First stop -
Second stop -
Air displacement
Dispensing
5 Steps of Micropippeting:
Set the volume
Attach pipette tip
Aspirate the liquid
Dispense the liquid
Eject the tip
Errors to avoid
Misaligned or improperly secured pipette tips
Inconsistent plunger pressure during operation
Submerging the tip too deeply or not deep enough in the liquid
Holding the pipette at an incorrect angle
Misaligned or improperly secured pipette tips
Ensure tips are properly attached to avoid leaks or inaccuracies.
Inconsistent plunger pressure
during operation
Apply consistent pressure to prevent uneven aspiration or dispensing.
Submerging the tip too deeply
or not deep enough in the liquid
Submerge the tip just 2–3 mm
below the liquid surface to avoid
air intake or excess uptake.
Holding the pipette at an incorrect angle
Keep the pipette vertical to maintain accuracy
Best practices in micropipetting
Pre-wet the pipette tip before use
Pipette slowly to avoid bubbles and ensure consistent aspiration
Always use the correct pipette and tip size for the volume being handled
Improves accuracy by equilibrating the pipette tip with the sample liquid.
Pre-wet the pipette tip before use
Prevents errors caused by trapped air or uneven liquid handling.
Pipette slowly to avoid bubbles and ensure consistent aspiration
Ensures precision and avoids overloading the pipette.
Always use the correct pipette and tip size for the volume being handled
Proper Micropipette Handling and Care
- Never force the volume adjustment dial beyond its range.
- Before storing, set the dial to the highest setting to release spring tension.
- Always store the pipette properly:
• Keep it vertically in a stand to
prevent internal damage.
• Avoid horizontal storage to
prevent liquid entry. - Clean the exterior with a lint-free cloth and mild detergent or 70% ethanol.
- Handle with care; accidental drops may require recalibration.
- Prevent liquid from entering the pipette body to avoid buildup and inaccuracies.
- Regular calibration is essential for accuracy.
