How to Use a Serological Pipette?

A pipette is a metering-out instrument that is used only to measure the volume of solution it releases and accurately pipettes a certain volume of solution. It is a slender glass tube with a bulge in the middle. The lower end is beak-shaped, and a marking line is engraved on the neck of the upper end, which is a sign of the exact volume removed.

The serological pipette is mainly used to accurately measure a certain volume of liquid and needs to be used with a suitable pipette. It’s suitable for tissue culture, bacterial culture, and clinical research experiments. The widely used manufacturing materials are polystyrene, glass, etc. In HAWACH, There are mainly 6 kinds of capacity specifications, namely 1.0ml, 2.0ml, 5.0ml, 10.0ml, 25.0ml, and 50.0mL, except that the tube body has different precision scale marks, different capacity specifications are marked with different color rings, which is more convenient for identification and use during work; some tube ends have filter plugs, which can better prevent cross-contamination when samples are drawn.

What Do You Need Before Using a Serological Pipette?

Before starting, prepare:

A suitable serological pipette
A compatible pipette controller or pipette aid
The source container
The receiving container
The liquid to be transferred
Appropriate personal protective equipment
Sterile working equipment when performing aseptic procedures

If the application involves cell culture or another contamination-sensitive workflow, use a sterile, individually packaged serological pipette when appropriate. Hawach offers sterile serological pipettes with options including DNase/RNase-free and non-pyrogenic specifications.

Before opening a sterile package, check the package integrity and expiration information according to your laboratory’s procedures.

Step 1: Select the Correct Pipette Size

Choosing the correct capacity is the first step toward efficient liquid transfer.

Using a very large pipette for a relatively small volume can make accurate volume adjustment more difficult. On the other hand, repeatedly filling a small pipette to transfer a large volume increases the number of operations and may increase handling time.

A practical selection approach is:

The appropriate size should ultimately be determined by the volume required, the vessel geometry, and the laboratory procedure.

Hawach’s current serological pipette range covers these six sizes, with different color codes for rapid identification.

Step 2: Connect the Pipette to the Pipette Controller

Remove the serological pipette from its packaging without touching the working end or other surfaces that must remain sterile.

Insert the upper end into the pipette controller carefully.

The connection should be secure but should not require excessive force. A loose connection can cause air leakage and unstable aspiration, while excessive force may damage the pipette or controller.

For sterile applications, avoid touching the pipette tip or placing it against non-sterile surfaces.

Step 3: Place the Pipette Into the Liquid

Hold the pipette approximately vertically and place the lower end into the liquid.

The pipette tip should be sufficiently immersed to prevent air from being aspirated, but it should not be pushed unnecessarily deep into the sample.

Excessive immersion can cause liquid to adhere to the outside of the pipette and may increase the risk of contamination when the pipette is removed.

For many routine procedures, a shallow and controlled immersion is preferable.

Step 4: Aspirate the Liquid Slowly

Use the pipette controller to draw liquid into the serological pipette.

Do not aspirate too aggressively.

A sudden increase in suction can cause:

Air bubbles
Splashing
Aerosol formation
Liquid entering the controller
Difficulty controlling the final volume

Instead, operate the aspiration control gradually and monitor the liquid level continuously.

Stop aspiration before the liquid reaches the controller or the upper end of the pipette.

If the pipette has a filter plug, do not deliberately wet or bypass the filter. A wet filter can interfere with airflow and may indicate that liquid has been aspirated too aggressively.

Step 5: Read the Graduation Correctly

Once the required amount of liquid has been aspirated, hold the pipette vertically and examine the graduation.

For transparent aqueous solutions, read the liquid level at eye level to reduce parallax errors.

The scale should be viewed straight on rather than from above or below.

This is particularly important when the liquid level falls between two graduation marks.

The reading method may also depend on the pipette design. Always follow the manufacturer’s calibration and graduation instructions for the specific product.

Step 6: Adjust the Volume

If the liquid level is above the required graduation, use the pipette controller to release a small amount of liquid.

Allow the liquid to move slowly rather than releasing it suddenly.

Bring the liquid level to the required graduation while keeping the pipette in a stable position.

Avoid repeatedly aspirating and dispensing the same liquid simply to obtain a target volume unless the procedure specifically requires pre-wetting or conditioning.

Once the correct volume has been reached, the pipette is ready for transfer.

Step 7: Move to the Receiving Vessel

Transfer the loaded pipette to the receiving container while keeping the pipette as stable as possible.

When moving between vessels, avoid allowing the tip to touch:

Laboratory benches
The outside of containers
Gloves
Non-sterile equipment
Other liquid surfaces

For sterile cell culture work, maintain appropriate aseptic technique throughout the transfer.

If the receiving vessel has a narrow opening, position the pipette carefully before dispensing to minimize splashing.

Step 8: Dispense the Liquid

Place the tip against the inside wall of the receiving vessel when appropriate.

Operate the pipette controller gradually and allow the liquid to flow out in a controlled manner.

Do not squeeze or force the pipette unless the specific pipette design and procedure require a blow-out step.

Some serological pipettes include graduations below the zero point or negative graduations. These markings can provide additional volume capacity and may also support complete delivery depending on the design.

The correct dispensing technique should always follow the pipette’s calibration method and manufacturer’s instructions.

Step 9: Complete the Delivery

After the main liquid has been dispensed, allow the liquid to drain according to the pipette’s intended delivery method.

For certain serological pipette designs, a small amount of liquid may remain in the tip after normal drainage. This does not necessarily mean the pipette has delivered an incorrect volume.

The amount remaining can be accounted for during the calibration of a pipette designed as a “to deliver” instrument.

Do not automatically force the remaining liquid out unless the pipette specification or laboratory procedure specifically requires a blow-out operation.

How to Use a Serological Pipette in Cell Culture?

Serological pipettes are particularly common in cell culture because relatively large volumes of media and reagents must frequently be transferred.

A typical workflow may include:

Select a sterile serological pipette with an appropriate volume.
Open the sterile package inside the appropriate aseptic environment.
Connect the pipette to a sterile or appropriately prepared pipette controller.
Aspirate culture medium or reagent without touching non-sterile surfaces.
Transfer the liquid to the culture vessel.
Dispense slowly to minimize splashing and aerosol formation.
Remove and dispose of the pipette according to laboratory procedures.

For cell culture, contamination control is just as important as volume control.

Hawach serological pipettes are manufactured from high-quality PS and are available with sterile packaging and cleanliness specifications designed for laboratory applications.

Features of Serological Pipette

The serological pipette can be made of glass or high-quality polystyrene (PS), and the novel design of the pipette mouth can be adapted to almost all brands of pipettes on the market. It can be sued in small-volume liquid measurement and transfer, which is applied in bacteriology, cell culture clinical, scientific research, and other fields.

•The raw material is polystyrene or glass
•Independent paper and plastic packaging
•Manufactured in 100,000 cleanroom
•Negative scale for extra volume
•Polyolefin filter element to prevent contamination
•Highly dropper-free tip design
•Slim profile enables ergonomic conditions inside the sterile hood
•In addition to the different precision scale marks on the tube body, different specifications with different colors for easy identification
•Each package has an independent item number and batch number identification, which is convenient for quality tracking and traceability

The correct use of methods and steps of the serological pipette

1. Before using: Before using a serological pipette, first look at the pipette marking, accuracy level, and position of the scale mark.

2. Liquid suction: Pinch the upper end of the pipette with the thumb and middle finger of the right hand, and insert the lower mouth of the pipe into the solution to be sucked. The insertion should not be too shallow or too deep, generally, 10~20mm, too shallow will produce Aspirate and suck the solution into the ear bulb to stain the solution, too deep and the solution will adhere to the outside of the tube too much. Take the ear-washing bulb in the left hand, connect it to the upper mouth of the tube, and slowly inhale the solution, first inhale about 1/3 of the capacity of the tube, hold the mouth of the tube with the index finger of the right hand, take it out, hold it horizontally, and turn the tube to make the solution come into contact with it. Place above the scale to replace the water on the inner wall, and then release the solution from the lower mouth of the tube and discard it. After repeated washing 3 times, the solution can be sucked up to about 5mm above the scale, and immediately press to the mouth of the tube with the index finger of the right hand.

3. Adjust the liquid level: lift the pipette up to leave the liquid level, and wipe off the liquid stuck on the outer wall of the serological pipette with filter paper, the end of the pipe is against the inner wall of the solution container, the pipe body is kept vertical, and the index finger is slightly relaxed. Make the solution in the tube slowly flow out from the lower mouth until the bottom of the meniscus of the solution is tangent to the marking line, and press the tube mouth immediately with the index finger. Remove the droplet against the wall, remove the pipette, and insert it into the vessel that holds the solution.

4. Release the solution: If the container for the solution is a conical flask, the conical flask should be tilted 30°, the disposable serological pipette should be kept vertical, the lower end of the pipe should be close to the inner wall of the conical flask, loosen the index finger, and let the solution slowly move along the bottle wall. Slowly flow down, when the liquid level drops to the discharge head and the tube touches the inner wall of the bottle for about 15 seconds, then remove the pipette. A small amount of solution remaining at the end of the tube cannot be forced to flow out with strong external force, because it has been taken into account when calibrating the volume of solution remaining at the end.