Among the many equipment used in the hospital or laboratory, the Pasteur pipette is one of them. Basically, they are used to help facilitate ease, effectiveness, balance, and perfection during and after the scientific processing of discovering new terrain. Given the importance of this efficient tool, this article is going to focus on the uses of Pasteur pipette and the general guide on the different types of pipettes and perhaps the essence of them.
In the 19th century, Louis Pasteur redesigned basic glass pipettes to make them more efficient. Over a hundred years later, Pasteur pipettes are still used to transfer liquids. These types of pipettes are typically made of glass or plastic, with a rubber bulb separate from the pipette body to control the flow of liquid. Pasteur pipettes are used to transfer small volumes of liquids and are not calibrated or marked with any volumetric guidelines.
What are Pasteur Pipettes?
Pasteur pipettes are plastic or glass pipettes used to transfer small amounts of liquids, but are not graduated or calibrated for any particular volume. The bulb is separate from the pipette body. Pasteur pipettes are also called teat pipettes, droppers, eye droppers and chemical droppers. Some of these pipettes are capable of being very precise and accurate.
However, since they rely on air displacement, they are subject to inaccuracies caused by the changing environment, particularly temperature and user technique.
For these reasons, this equipment must be carefully maintained and calibrated, and users must be trained to exercise correct and consistent technique.
There are nonetheless other two types of pipettes after Pasteur. These are:
- Positive Displacement
- Air Displacement
Characteristics of Pasteur Pipettes
- Made of Glass and Plastic
- Easy and safe to use
- Ideal for Clinical and Industrial use
- Chemical Resistant
- Economical
- Environment friendly
Uses of Pasteur Pipette and the General Guide
There are several uses of Pasteur pipette and the general guide will be duly and comprehensively analyzed for you to have a full glimpse of the value which this very wonderful scientific tool shares. First of all, we will taking you through some of the functions and uses of Pasteur Pipette.
- Pasteur pipette are basically used to transfer small quantities of liquids
- They are also used for blood banks
- They are used in bacteriology labs and also in hematology labs including for other general laboratory applications
- Pasteur pipettes are efficient for research and development programmes in the laboratories
The Calibration of Pipette and Guide
The calibration process checks whether or not the equipment is dispensing the proper volumes by determining the difference between the dispensed volume and the selected volume. Calibration ensures accuracy, and the process and steps vary between pipette type and model.
Atmospheric pressure, humidity, and temperature can all influence measurement accuracy over time. In the calibration process, the combination of these factors generates a Z factor, which can be applied in the calculation of water volume to determine pipette accuracy.
Pipettes should be calibrated every 3-6 months as recommended by the Clinical and Laboratory Standards Institute (CSLI). This refers to single and multi-channel pipettes, as well as automated pipettes. Pipettes can be sent to companies that specifically service for recalibration.
Sub-Types of Pipettes
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Graduated Pipettes
Graduated pipettes refer to various types of macro pipettes that are classified by a sequence of graduations to show different volumes. These pipettes include other variations and require a type of suction to transfer the liquid.
When choosing a graduated pipette, the recommendation is for the nearest size pipette to the liquid volume that is needed to work with. Rinse the pipette before use. Hold the pipette tip in the solution that needs to be transferred at a 90-degree angle without touching the bottom of the beaker. Then, use the rubber or plastic bulb to slowly draw the liquid in until the desired volume has been reached. During the process, the pipette must be held upright. The solution will form a meniscus (curved upper surface of the liquid in the tube). To properly read the volume, look at the meniscus at eye level. For low viscosity liquids, the volume is measured at the lower meniscus. For high viscosity liquids, the volume is measured at the upper meniscus. The solution should be dispersed by releasing the pressure and holding the pipette at a 45-degree angle.
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Serological Pipettes
A serological pipette is a type of graduated pipette used for transferring liquid in milliliter volumes and is determined by its graduation marks that start closer to the tip. Serological pipettes are blow-out pipettes, which are pipettes that are designed to be blown out by either external air pressure or gravitation force. Serological pipettes can come in different sizes, from 0.1 ml to 50 ml, and are available in bulk. Serological pipettes like these are manufactured from optically clear polystyrene and along with being calibrated for accuracy, they are gamma irradiation sterilized.
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Volumetric Pipettes
Volumetric pipettes allow for precise accuracy. Volumetric pipettes have long slender necks above and below a large bulb, with one graduation mark. Volumetric pipettes are calibrated for single volumes typically ranging from 1, 5, 10, 20, 25, 50, and 100 ml and are made from borosilicate glass. Borosilicate glass is a favorite among professionals as its natural properties defend against mechanical stress, chemicals, and thermal shift.
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Micropipettes
Micropipettes are used for transferring extremely small quantities of liquid from 0.5 μL to 1000 μL. Micropipettes come in different sizes for different volumes of liquid, and both variable and fixed pipettes correspond with a volume bracket.
