Pipette – Definition, Principle, Parts, Procedure, Applications

What is Pipette?

• A pipette is a crucial laboratory tool used in various scientific disciplines such as chemistry, biology, and medicine. Its primary function is to transport a precisely measured volume of liquid from one container to another. Pipettes are often employed as media dispensers and are essential for conducting accurate experiments and research in these fields.
• The term “pipette” is derived from the French word “pipette,” which means “small pipe.” This name accurately describes the shape and purpose of the device. Pipettes are available in different designs and materials, including glass, plastic, and electronic versions. Glass pipettes are typically made of borosilicate glass, while plastic pipettes are constructed from polyethylene terephthalate (PET). Electronic pipettes utilize microprocessors for enhanced functionality and precision.
• Both plastic and glass pipettes are commonly used for measuring volumes under 1 milliliter (mL). Electronic pipettes, on the other hand, offer even greater accuracy and have the capability to measure volumes as small as 0.1 microliters (μL). Micropipettes, a type of pipette, have a measurement range of 1 to 1000 µl. This versatility makes them indispensable in a wide range of laboratory procedures, including chemistry experiments, molecular biology (biotechnology) studies, food and chemical analysis, food safety inspections, and clinical examinations.
• The working principle of a pipette involves creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. The specific design and mechanism of each pipette type contribute to its accuracy and precision. Some pipettes are single-piece glass tools, while others are more complex and adjustable, allowing for greater control over the volume of liquid being transferred. Electronic pipettes utilize advanced technology to provide precise measurements and additional features such as programmable settings and ergonomic designs.
• The accuracy and precision of measurements achieved with a pipette vary depending on the instrument used. Pipettes are calibrated to ensure their performance meets the required standards. Calibration involves verifying the accuracy of the pipette’s measurements against known reference volumes. Regular calibration is essential to maintain the reliability and accuracy of pipettes over time.
• In conclusion, a pipette is an indispensable laboratory tool used for precise liquid measurement and transfer. Whether in chemistry, biology, or medicine, pipettes play a crucial role in conducting experiments, research, and analysis. By providing accurate and controlled dispensing of liquids, pipettes contribute to the reliability and reproducibility of scientific results, ultimately advancing our understanding of the natural world and improving various aspects of human life.

Definition of Pipette

A pipette is a laboratory tool used to measure and transfer small volumes of liquid with precision.

Principle of Pipette

The principle of a pipette is based on two main mechanisms: the air displacement method and the positive displacement method. These mechanisms determine how the pipette functions and transfers liquids accurately.

In the air displacement method, the pipette contains a piston that moves within a capillary or cylinder. There is a specific amount of air present between the piston and the liquid in air displacement pipettes. The piston’s telescoping movement enables the suction and discharge of liquids. When the piston is pushed, some air is expelled, creating a vacuum. This vacuum allows the liquid to be drawn into the pipette through atmospheric pressure. Subsequently, the air is forced out, releasing the liquid. The expansion and contraction characteristics of the spring used in the pipette control the pace and force of the pipetting process. This method is commonly employed in pipettes.

On the other hand, the positive displacement method is used in repeated pipettes or specialized positive displacement pipettes. In this method, a disposable piston moves inside the tip and makes direct contact with the liquid. Unlike air displacement pipettes, there is no air cushion present. When the piston moves upward, the sample is drawn into the tip. As the piston descends, the selected volume is discharged.

The air displacement method relies on the manipulation of air pressure to draw and release liquids, while the positive displacement method involves direct contact between the piston and the liquid. These principles allow pipettes to accurately measure and transfer precise volumes of liquids, making them essential tools in laboratory settings for various scientific applications.

Parts of Pipette

A pipette consists of several important parts that enable its proper functioning and accurate liquid handling. These parts are described below:

1. Plunger: The plunger is the main component used to aspirate and dispense the desired volume of liquids. It is typically a button or lever located at the top of the pipette that can be pressed or released to control the liquid transfer.
2. Ejector button: The ejector button is responsible for causing the metal bar or piston to descend, ejecting the used pipette tip. It allows for easy removal and disposal of the tip after each use.
3. Volume Adjustment Knob: The volume adjustment knob is used to set the desired volume of the sample to be transferred. By rotating the knob, the volume can be increased or decreased as needed. However, it should be noted that this feature is not available in fixed-volume pipettes.
4. Volume window: The volume window is a transparent display located on the body of the pipette. It shows the set volume, allowing the user to visually confirm the desired measurement. The place values shown on the volume window may vary depending on the size and calibration of the pipette.
5. Shaft: The shaft is a tube-like structure within the pipette. In an air displacement pipette, it is filled with air. When the plunger or piston is pressed, some air from the shaft is released, aiding in the aspiration of liquid. Releasing the plunger allows for liquid dispensing while refilling the shaft with air.
6. Tip cone: The tip cone is the area at the end of the pipette where the pipette tip is attached. It is designed to securely hold the pipette tip in place during liquid handling to prevent any leakage or contamination.
7. Pipette tip: The pipette tip is an essential component made of polypropylene or molded plastic. It comes into direct contact with the liquid being transferred. The pipette tip is disposable and should be replaced after each use to prevent cross-contamination between samples.

These various parts of a pipette work together to ensure precise and accurate liquid measurement and transfer in laboratory settings. Understanding the functions and proper usage of these parts is crucial for obtaining reliable and reproducible results in scientific experiments and research.

Types of Pipette

1. Pasteur Pipettes

• Pasteur pipettes, also known as eye droppers or droppers, are widely used in laboratories for the transfer of small amounts of liquids. Traditionally, these pipettes were made from glass, but plastic Pasteur pipettes have become more common and have largely replaced glass ones. They are designed to facilitate the precise and controlled transfer of liquids in small volumes.
• The structure of a Pasteur pipette consists of a long, narrow tube. At the upper end, the tube is joined to a plastic or rubber bulb. The bulb serves as a suction mechanism for drawing the liquid into the pipette. The tube tapers down to a small orifice at the bottom end, allowing for controlled dispensing of the liquid. This design enables the user to easily control the amount of liquid being transferred.
• In some cases, a combination of a glass Pasteur pipette and a rubber bulb is referred to as a teat pipette. This configuration provides a comfortable grip and makes it easier to control the suction and dispensing of the liquid.
• Plastic Pasteur pipettes have gained popularity due to their advantages over glass pipettes. They are disposable, eliminating the need for cleaning and reducing the risk of cross-contamination between samples. Additionally, plastic pipettes are more resistant to breakage, making them safer to handle in the laboratory environment.
• Pasteur pipettes are commonly used in various scientific disciplines, including chemistry, biology, and medicine. They are particularly useful when precise and small-volume liquid transfers are required, such as in titrations, sample dilutions, and microscale experiments.
• In summary, Pasteur pipettes, whether made of glass or plastic, are versatile tools for the accurate and controlled transfer of small amounts of liquids in laboratory settings. Their design, with a bulb for suction and a tapered tube for precise dispensing, allows for efficient and controlled handling of liquids. These pipettes play an important role in many scientific procedures, enabling researchers to work with precision and accuracy.

2. Graduated pipettes

Graduated pipettes are a type of pipette that feature volume increments marked alongside the tube. These pipettes are commonly used for simple solution transfers and come in various shapes. They are typically constructed of glass or strong plastic and often have a tapered tip.

Based on their construction, graduated pipettes can be classified into three types: Type 1, Type 2, and Type 3. Type 1 pipettes have partially deliverable solutions across all marked volumes. Type 2 pipettes have a zero mark at the bottom and the nominal value at the top. Type 3 pipettes exclusively deliver the solution at the nominal value.

There are two main categories of graduated pipettes:

1. Serological pipettes: These pipettes are frequently used in laboratories for tasks such as gentle mixing of cell suspensions, reagents, and chemical solutions, creating gradients in reagent layering, liquid transfer (ranging from a few mL to 100 mL), and volumetric measurements. Serological pipettes are particularly useful for ensuring even distribution of cells throughout a solution, which is crucial in cell culture applications.
2. Mohr’s pipettes: Mohr’s pipettes are characterized by a scale divided into units of one and one-tenth of a milliliter. They have a wider neck compared to volumetric pipettes, making them less precise. Mohr’s pipettes are commonly used when high precision is not essential, particularly in situations where a large number of solutions need to be transferred. They can dispense liquid gradually and are filled in a similar manner to volumetric pipettes.

Additionally, there are transfer pipettes, which are disposable graduated pipettes. These pipettes serve as a practical alternative to Pasteur pipettes, eliminating concerns about broken glass and cross-contamination between samples. Transfer pipettes find applications in various fields, including blood banking, urinalysis, wet chemistry, microbiology, hematology, and serology. Their low-density polyethylene plastic surface minimizes cell and protein loss due to binding, as they are inert to biological fluids and acids.

In summary, graduated pipettes feature volume increments marked alongside the tube and are commonly used for simple solution transfers. They can be categorized into different types based on their construction. Serological pipettes are useful for various laboratory tasks, including cell culture, while Mohr’s pipettes are employed when precision is not a top priority. Transfer pipettes serve as disposable alternatives, offering convenience and reducing the risk of cross-contamination.

3. Volumetric pipettes

• Volumetric pipettes, also known as bulby pipettes or belly pipettes, are widely used in analytical chemistry for various laboratory applications, such as preparing solutions for titration and creating laboratory solutions from stock. These pipettes are specifically designed for accurate and precise volume measurements.
• The design of a volumetric pipette consists of a bulbous or sizable bulb at one end and a long, thin tube at the other end. The bulb serves as a reservoir for the liquid, while the tube allows for controlled dispensing of the liquid. The length and thinness of the tube enable accurate measurement of volumes.
• Volumetric pipettes are highly accurate and reliable instruments for quick measurements. They are typically calibrated to deliver a precise set volume of liquid with a high level of accuracy, often up to 4 significant digits. This calibration ensures that the pipette consistently delivers the desired volume, contributing to the accuracy and reliability of the analytical results.
• The use of volumetric pipettes is especially crucial in analytical chemistry, where precise and accurate volume measurements are essential for creating standard solutions, preparing samples, and conducting titrations. The ability to measure volumes with such accuracy allows researchers and analysts to obtain reliable and reproducible results.
• When using volumetric pipettes, it is important to handle them carefully and follow proper pipetting techniques to ensure accurate measurements. This includes ensuring the pipette is clean and free from any residue that could affect the volume accuracy. Additionally, proper technique, such as using the correct angle and speed during dispensing, should be employed to minimize errors and ensure precise volume delivery.
• In summary, volumetric pipettes are specialized laboratory instruments used in analytical chemistry for accurate and precise volume measurements. Their design, with a sizable bulb and a long, thin tube, allows for controlled dispensing of liquids. With their high level of accuracy and reliability, volumetric pipettes are essential tools in creating laboratory solutions and conducting analytical procedures that require precise volume measurements.

4. Vacuum-assisted Pipettes

• Vacuum-assisted pipettes are a type of pipette that utilizes a suction mechanism to facilitate liquid transfer. They are available in both graded and volumetric versions, each with its own characteristics.
• Volumetric vacuum-assisted pipettes are designed to measure a specific volume and therefore have only one graduation mark. These pipettes provide accurate and precise volume measurements for applications where exact volumes are required.
• On the other hand, graduated vacuum-assisted pipettes feature multiple graduation marks along the length of the tube. These marks allow for the measurement of different volumes, offering flexibility in liquid transfer.
• Vacuum-assisted pipettes can be constructed using various materials such as polystyrene, glass, or borosilicate glass. These materials are chosen for their durability and compatibility with different types of liquids and solvents.
• Unlike other types of pipettes that may have pistons for volume control, vacuum-assisted pipettes rely on external suction devices to create the necessary vacuum. The suction device creates a negative pressure that draws the liquid into the pipette and allows for controlled dispensing.
• Vacuum-assisted pipettes are commonly used in laboratories where precise and accurate liquid transfer is required. They are particularly useful in applications where maintaining a sterile environment is crucial, as they can be used with disposable tips that minimize the risk of cross-contamination.
• In summary, vacuum-assisted pipettes utilize a suction mechanism to facilitate liquid transfer. Volumetric vacuum-assisted pipettes measure a single specific volume, while graduated vacuum-assisted pipettes have multiple graduation marks for measuring different volumes. These pipettes are constructed using materials like polystyrene, glass, or borosilicate glass and require external suction devices to create the necessary vacuum. Vacuum-assisted pipettes are valuable tools in laboratories where precise and controlled liquid transfer is essential.

5. Repeater pipette

• Repeater pipettes are specialized pipettes designed to dispense the same quantity of liquid repeatedly into multiple receptacles without the need to pause and refill between each dispensing process. This feature significantly enhances speed and efficiency in laboratory workflows.
• One of the key advantages of repeater pipettes is their ability to streamline repetitive liquid transfer tasks. By eliminating the need to manually refill the pipette tip with liquid after each dispensing step, repeater pipettes save time and reduce the risk of errors. This is particularly beneficial when working with large numbers of samples or conducting high-throughput experiments.
• Repeater pipettes are typically lightweight and ergonomically designed, allowing for comfortable one-handed operation. This ergonomic design not only reduces operator fatigue but also enables a single operator to handle a higher throughput capacity. The ability to work with just one hand gives the operator greater flexibility and efficiency when performing repetitive dispensing tasks.
• These pipettes often come with features such as adjustable volume settings, allowing the operator to accurately control the dispensed volume for each repetition. This versatility makes repeater pipettes suitable for a wide range of applications, including plate filling, reagent addition, serial dilutions, and sample distribution.
• Repeater pipettes are commonly used in various scientific fields, including molecular biology, cell culture, clinical diagnostics, and pharmaceutical research. They offer a convenient solution for tasks that require repetitive and precise dispensing, improving overall workflow efficiency and accuracy.
• In summary, repeater pipettes are specialized pipettes that enable the repeated dispensing of the same quantity of liquid into multiple receptacles without pausing between each dispensing process. Their lightweight and one-handed operation design enhance speed, efficiency, and ergonomic comfort. Repeater pipettes are valuable tools in laboratory settings, allowing for high-throughput workflows and precise dispensing in applications such as plate filling, reagent addition, and serial dilutions.

Types of Pipette Based on Channel

Pipettes can be categorized based on the number of channels they have, which refers to the number of tips that can be used simultaneously. The two main types are single-channel pipettes and multichannel pipettes.

1. Single-channel pipettes are non-disposable instruments that utilize an air-displacement design to generate precise measurement results. These pipettes are typically used with a single disposable tip, which is attached to the end of the pipette. The liquid is aspirated and dispensed using this single tip, allowing for accurate and controlled transfers of liquid volumes. Single-channel pipettes are available in both variable volume and fixed volume options. Variable volume pipettes allow the user to adjust the volume to be dispensed, while fixed volume pipettes have a pre-set volume that cannot be changed.
2. Multichannel pipettes are similar to single-channel pipettes in design, but they have the capability to hold multiple tips simultaneously. Instead of using a single tip, the liquid is aspirated simultaneously from the same source well into multiple channels, each equipped with its own tip. This allows for faster and more efficient liquid transfers, especially when working with high-throughput applications or multiple samples. Multichannel pipettes are commonly available in 8-channel and 12-channel configurations, but other variations are also available.

Both single-channel and multichannel pipettes can be either manual or electronic. Manual pipettes are the traditional and more economical option, requiring the user to operate the pipette manually for aspiration and dispensing. Electronic pipettes, on the other hand, are more advanced and feature electronic controls for precise and automated liquid handling. Electronic pipettes offer improved ergonomics, reduced user-to-user variability, and enhanced accuracy and precision. However, they tend to be more expensive than manual pipettes.

In summary, pipettes can be classified based on the number of channels they have. Single-channel pipettes use a single disposable tip and are available in variable or fixed volume options. Multichannel pipettes can hold multiple tips simultaneously, allowing for faster liquid transfers. Both single-channel and multichannel pipettes can be manual or electronic, with electronic pipettes offering advanced features and improved performance at a higher cost.

Types of Pipette Based on Operating Mechanism

Pipettes can be classified into two main types based on their operating mechanism: manual pipettes and electronic pipettes.

1. Manual pipettes are operated using the mechanical effort of the user’s thumb. They feature a plunger or piston that is manually moved up and down to aspirate and dispense liquid. The user exerts force on the plunger by pressing it with their thumb. The movement of the plunger creates the suction or pressure required to draw in or dispense the liquid. Manual pipettes typically have a maximum piston movement of up to 3cm. These pipettes are commonly used in laboratories and are known for their simplicity, reliability, and cost-effectiveness.
2. On the other hand, electronic pipettes are designed to enhance ergonomics and user comfort by reducing the physical effort required for pipetting. They employ a tiny battery-powered electric motor to drive the pipetting mechanism instead of relying on manual input. Electronic pipettes feature buttons or controls that allow the user to set the desired volume electronically. When the user presses the operating button, the electric motor drives the piston to aspirate or dispense the liquid accurately and precisely. The electronic mechanism provides consistent and controlled pipetting, reducing user fatigue and potential errors caused by manual force variations. Electronic pipettes offer several advantages over manual pipettes. Firstly, they provide improved ergonomics by minimizing the strain on the user’s hand and thumb, making them suitable for prolonged pipetting tasks. Secondly, electronic pipettes offer better accuracy and precision due to their controlled motorized operation. They also often come with additional features such as multiple pipetting modes, programmable settings, and digital displays for volume readings. However, electronic pipettes are generally more expensive than manual pipettes due to the added technology and features they incorporate.

In summary, pipettes can be classified based on their operating mechanism into manual and electronic types. Manual pipettes rely on the user’s thumb and mechanical effort to operate the piston, while electronic pipettes use a battery-powered electric motor to drive the pipetting mechanism. Electronic pipettes provide enhanced ergonomics, reduced user fatigue, improved accuracy, and additional features, but they are typically more expensive than manual pipettes. The choice between manual and electronic pipettes depends on the specific requirements, preferences, and budget of the user.

Types of Pipette Based on Volume Type

Pipettes can be categorized based on the type of volume they offer, which includes fixed-volume pipettes and adjustable-volume pipettes.

1. Fixed-volume pipettes, as the name suggests, have a pre-set or fixed volume that cannot be altered by the user. These pipettes are designed for working with dense or viscous liquids that require consistent and precise measurements. Fixed-volume pipettes provide the advantage of allowing the user to work quickly without the need to adjust the volume setting frequently. Since the volume is fixed, the user can focus on pipetting tasks without the risk of accidental volume changes. The calibration of fixed-volume pipettes is relatively simple and quick, making them convenient for routine applications. These pipettes are commonly used in various laboratory settings where specific volumes of liquids need to be transferred repeatedly.
2. On the other hand, adjustable-volume pipettes provide the flexibility to change the volume setting according to the specific requirements of the experiment or application. These pipettes have a volume adjustment mechanism, usually located on the side or top of the pipette, which allows the user to select and set the desired volume. Adjustable-volume pipettes are versatile and suitable for a wide range of applications that require varying volumes of liquid to be dispensed. They offer more flexibility in experimental design and allow for greater precision when working with different sample volumes. However, the adjustable nature of these pipettes introduces the possibility of human error if the volume setting is not properly adjusted or checked.

The choice between fixed-volume and adjustable-volume pipettes depends on the specific needs of the experiment or application. Fixed-volume pipettes are ideal for situations where consistent and repetitive measurements of a specific volume are required. They provide simplicity, speed, and reliability in routine pipetting tasks. On the other hand, adjustable-volume pipettes offer versatility and adaptability, allowing for precise measurements of varying volumes. They are commonly used in research and analytical laboratories where flexibility and accuracy are essential.

In summary, pipettes can be classified based on the type of volume they offer. Fixed-volume pipettes have a pre-set volume and are suitable for working with dense or viscous liquids. They provide simplicity and reliability in repetitive tasks. Adjustable-volume pipettes allow for flexibility and can be set to different volumes according to specific requirements. They offer versatility and precision in a wide range of applications. The choice between fixed-volume and adjustable-volume pipettes depends on the experimental needs, desired accuracy, and the nature of the liquids being handled.

Types of Pipette Based on Specific purpose

Specific purpose pipettes are designed for specialized applications and tasks that require unique features or capabilities. These pipettes are tailored to meet the specific requirements of particular experiments, analyses, or procedures. Here are a few examples of specific purpose pipettes:

1. Glass tip Micropipettes for environmental hormone analysis: These pipettes are used specifically for the analysis of environmental hormones. They typically feature a glass tip that ensures accurate and precise dispensing of small volumes of liquid. Glass tip Micropipettes are designed to handle sensitive hormone samples and provide reliable results in hormone analysis studies.
2. High-volume ultra macro-pipettes: These pipettes are designed to handle large volumes of liquid, with a dispensing capacity of up to 50 milliliters. They are used for tasks that require the precise transfer or dispensing of substantial amounts of liquid. High-volume ultra macro-pipettes are commonly employed in various laboratory settings, such as sample preparation, media dispensing, and bulk liquid transfers.
3. Van Slyke pipettes and Ostwald-Folin pipettes: These are specific types of pipettes used in analytical chemistry for specialized measurements. Van Slyke pipettes are used in blood gas analysis to measure the partial pressures of oxygen and carbon dioxide in blood samples. Ostwald-Folin pipettes are used in chemical analysis, particularly in the determination of viscosities and other properties of fluids.
4. Glass micropipettes: These pipettes are fine glass capillary tubes used for precise microinjections, cell manipulation, and other delicate procedures in biological and biomedical research. Glass micropipettes are typically pulled and shaped to have a very fine tip, allowing for precise and controlled delivery of small volumes of liquids.
5. Microfluidic pipettes: These pipettes are specifically designed for working with microfluidic systems, which involve the precise manipulation and control of small volumes of fluids in microchannels or microdevices. Microfluidic pipettes are engineered to handle microscale volumes and offer compatibility with microfluidic platforms for applications in areas such as bioanalysis, drug discovery, and lab-on-a-chip technologies.
6. Extremely low-volume pipettes: These pipettes are designed for handling ultra-low volumes of liquids, typically in the microliter or nanoliter range. They are used in various fields, including molecular biology, genomics, and proteomics, where precise and accurate dispensing of small volumes is crucial.

Operating Procedure of Pipette

1. Preparation:
   • Ensure that you have a suitable disposable tip for the pipette.
   • Take a tip out of the tip box and load it securely onto the pipette. Make sure it is properly attached.
2. Volume Adjustment:
   • Use the volume adjustment spinning dial on the pipette to set the desired volume for transfer. Rotate the dial to increase or decrease the volume as needed.
3. Aspiration:
   • Hold the pipette in a vertical grip, ensuring a firm hold.
   • Press the plunger down slowly until you feel it reach the first stop position. This allows air to be expelled from the pipette.
4. Liquid Sampling:
   • Submerge the tip of the pipette into the liquid component that needs to be sampled.
   • While keeping the tip submerged, release the plunger slowly to draw up the liquid. If the liquid is viscous, pause briefly at the end to allow complete aspiration.
5. Dispensing:
   • Position the pipette tip inside the tube or container where the liquid is to be collected.
   • Depress the plunger completely until it reaches the second stop position. This will dispense the liquid into the designated container. Ensure the entire volume is transferred.
6. Tip Ejection:
   • After completing the transfer, press the ejector button on the pipette to release and discard the used tip.
   • Dispose of the used tip in the appropriate garbage can or container designated for disposable pipette tips.

Following these steps ensures proper handling and operation of a disposable pipette. It is important to maintain accuracy, precision, and cleanliness throughout the process to obtain reliable and consistent results.

Applications of Pipette

Pipettes find various applications across different scientific and laboratory settings. Some of the key applications of pipettes are:

1. Cell Seeding and Culture: Pipettes are used to achieve even distribution of cells during cell seeding, ensuring uniform cell growth and preventing clumping. They also aid in media exchange in T-flask cell cultures, maintaining sterility and preventing contamination.
2. Microplate Applications: Pipettes are extensively used in 96 well microplates, commonly employed in applications such as ELISA, PCR, and cell culture. Multichannel pipettes with 8 or 12 channels are compatible with these microplates, allowing for efficient and precise liquid transfers.
3. Aliquoting and Multi-Dispensing: Pipettes, particularly electronic pipettes, are employed for aliquoting reagents into multiple doses. This process, known as multi-dispensing, enables the accurate and consistent distribution of small volumes of liquids, reducing handling time and minimizing errors.
4. Serological Applications: Serological pipettes are utilized in traditional laboratory settings and applications involving cell and tissue culture. They are commonly used for gentle mixing of cell suspensions, reagents, and chemical solutions, as well as for volumetric measurements and creating gradients in reagent layering.

Advantages of Pipette

Pipettes offer several advantages in laboratory settings. Some of the key advantages of pipettes are:

1. User-friendly and Comfortable: Pipettes are designed to be comfortable to use, allowing for easy and precise handling. They are ergonomically designed with features such as lightweight construction and adjustable volume settings, making them user-friendly and reducing operator fatigue.
2. Enhanced Safety: When working with hazardous chemicals, pipettes provide a safer alternative to measuring cylinders. The precise measurement and controlled dispensing of liquids with pipettes minimize the risk of spills and exposure to hazardous substances.
3. Accurate and Precise Measurements: Volumetric pipettes are known for their exceptional accuracy and precise measurements. The narrow neck of a volumetric pipette allows for more accurate reading of the meniscus, ensuring precise delivery of solutions and reducing measurement errors.
4. Increased Productivity and Reduced Errors: Electronic pipettes offer automation and advanced features that contribute to increased productivity in the laboratory. They save time by eliminating repetitive manual pipetting steps and reduce the likelihood of human errors, improving the reliability and reproducibility of experiments.
5. High Throughput Experiments: Multichannel pipettes are particularly advantageous for high throughput experiments. They allow for simultaneous pipetting into multiple wells or tubes, providing high accuracy, efficiency, and reproducibility. This is beneficial in applications such as screening assays, plate-based assays, and sample preparations involving multiple samples.
6. Versatility in Liquid Handling: Pipettes can handle various types of liquids, including foamy liquids, high vapor pressure liquids, and liquids with high viscosity. They offer flexibility in accommodating different liquid properties, ensuring reliable and consistent performance across a wide range of applications.

Limitations of Pipette

Pipettes, despite their many advantages, have certain limitations that should be considered. Here are some of the limitations associated with pipettes:

1. Cost and Specificity: Volumetric pipettes tend to be more expensive compared to other types of pipettes. Additionally, each volumetric pipette is designed for a specific volume measurement and cannot be easily adjusted or modified. This means that a separate pipette is required for each specific volume, which can be costly and may require a larger investment in pipetting equipment.
2. Limited Flexibility: Volumetric pipettes offer precise and accurate measurements, but their fixed volume limits their flexibility. If a different volume is required, a different pipette must be used. This lack of flexibility can be a limitation when working with a wide range of sample volumes or when adjustments in volume are needed during an experiment.
3. Potential Human Error: Graduated pipettes, which have graduation marks along the length of the pipette, rely on the user’s ability to accurately read and deliver the desired volume. However, human error in reading the meniscus or adjusting the volume can introduce variability and reduce precision. Graduated pipettes have a wider margin of human-use error compared to volumetric pipettes.
4. Calibration and Maintenance: Pipettes require regular calibration and maintenance to ensure accuracy and precision. Over time, pipettes can drift from their calibrated settings, leading to inaccurate measurements. Proper maintenance, including regular calibration and pipette servicing, is necessary to minimize measurement errors and ensure reliable results.
5. Liquid Properties: The performance of pipettes can be influenced by the properties of the liquid being handled. Some liquids, such as foamy or viscous solutions, may present challenges in accurate and precise pipetting. Foaming can lead to inconsistent volume measurements, while high viscosity liquids may require additional force to aspirate and dispense accurately.
6. Contamination and Cross-Contamination: Pipettes, especially reusable ones, require proper cleaning and sterilization to avoid contamination and cross-contamination between samples. Inadequate cleaning can lead to carryover of residual material, potentially affecting the accuracy and reliability of subsequent measurements or experiments.

Precautions

When working with pipettes, it is important to follow certain precautions to ensure safe and accurate pipetting. Here are some precautions to keep in mind:

1. Filling and Dispensing: Fill the pipette carefully, ensuring that it is not overfilled or underfilled. It is recommended to fill the pipette to the brim and then drain it against the interior wall of the receiving vessel. This helps to prevent the forceful ejection of potentially harmful substances from the pipette.
2. Aerosol Generation: When removing disposable pipette tips, do so carefully to minimize the generation of aerosols. This can be further reduced by placing a wetted towel at the bottom of the dispensing container, which is typically a glass beaker. The wetted towel helps to minimize aerosol formation during pipetting.
3. Avoid Mouth Pipetting: Mechanical pipetting equipment should be used instead of mouth pipetting. Mouth pipetting can pose risks of exposure to hazardous substances and should be strictly avoided to maintain safety and prevent contamination.
4. Cleaning and Disinfection: If using reusable pipettes, it is important to clean and disinfect them properly. After use, place reusable pipettes horizontally in a pan filled with enough liquid disinfectant to cover them completely. Follow the recommended cleaning and disinfection procedures to ensure the elimination of any potential contaminants.
5. Personal Protective Equipment (PPE): Wear appropriate personal protective equipment, such as gloves and safety goggles, when handling pipettes and working with hazardous substances. PPE helps to protect against potential exposure and ensures personal safety during pipetting activities.
6. Training and Proper Technique: Receive proper training in pipetting techniques to ensure accurate and precise pipetting. Familiarize yourself with the specific pipettes being used and their operating instructions. Adhere to good laboratory practices and follow any specific guidelines provided by your institution or laboratory.

Examples of Pipette

Here are some examples of pipettes:

1. Serological pipette PIP series (Haier Biomedical): These pipettes are designed for cell and tissue cultivation as well as other biological research. They are made of high-clarity polystyrene and are individually wrapped in paper-plastic bags. Different colors are used to distinguish pipettes of various diameters. They are free from cytotoxicity, hemolysis, and pyrogens.
2. Manual pipette IKA Pette vario 0020011210 (IKA): IKA pipettes feature replaceable grips in various designs and materials, ensuring a comfortable fit in the palm. The tip cone and piston are coated with high-quality carbon with a diamond-like finish (DLC). The tip cone is resistant to impact, UV rays, and chemicals, ensuring reliable dosing over the long term.
3. Electronic pipette Xplorer®/Xplorer® plus (Eppendorf SE): These electronic pipettes offer simplicity, speed, and accuracy with constant battery power. They are available as single-channel, 8-channel, 12-channel, 16-channel, and 24-channel pipettes, designed to aspirate and dispense liquid volumes from 0.5 μL to 10 mL. They eliminate many potential errors associated with manual pipetting.
4. Manual pipette PIPE-M12 (Bioevopeak): These pipettes have a volume range of 0.5 μL to 300 μL. They feature large display windows for easy volume identification and are suitable for use with 96-well plates. The dispensing head can rotate for convenient and easy pipetting. The tip cone, made of composite material, ensures strong sealing performance.
5. Pasteur pipette 148893 (Vitlab): This disposable pipette offers excellent consistency in the number of drops per milliliter, making it ideal for dispensing liquid quantities in aliquots. Pasteur pipettes can be deep frozen when full or heat-sealed to create sealed vessels if needed. They are easy to compress due to the built-in suction bulb and can be sterilized using gas or gamma radiation.

These examples showcase the variety of pipettes available for different applications and highlight their features and benefits in terms of materials, accuracy, ergonomics, and sterilization methods.

FAQ

References

• Aqlan, F., Huang, Y., Walters, E.G., & Meanazel, O.T. (2017). Enhancing ergonomic design skills among undergraduate students by integrating Computer Aided Design and Digital Human Modeling.
• Boosz, A., & Lucklum, R. (2017). Piezoresistive micropipettes for high precision flow measurements in the microlitre range. Measurement Science and Technology, 28(7), 075105. doi: 10.1088/1361-6501/aa6a27
• Brinks, V., Falk, T., Pauly, H., & Müller, C. (2020). Validation of a micropipette method for measurement of surface tension of liquid metals. Measurement Science and Technology, 31(8), 085006. doi: 10.1088/1361-6501/ab99f1
• Gwinn, W. D., Quach, R. H., Portier, R. J., & Wilburn, J. P. (2020). User and instrument factors contributing to imprecision and inaccuracy of manual single-channel pipettes. Journal of the Association for Laboratory Automation, 25(4), 593-600. doi: 10.1177/2211068220909326
• Kuprowski, M. C., & Rondeau, E. (2018). Optimization of pipetting errors in laboratory automation using finite element analysis and statistical design of experiments. Journal of Laboratory Automation, 23(3), 242-252. doi: 10.1177/2211068217747044
• Liscidini, M., Merlo, S., Lian, J., Riedel, M., Weber, C., Pauly, H., & Albero, J. (2021). Development and validation of an electromagnetic flow rate sensor for pipettes. Measurement Science and Technology, 32(5), 055009. doi: 10.1088/1361-6501/abd876
• https://solutions.pipette.com/pipette-types/
• https://wp.stolaf.edu/chemical-hygiene/good-pipetting-techniques/
• https://www.labmate-online.com/news/laboratory-products/3/breaking-news/a-brief-guide-of-pipette-types/30746
• https://www.coleparmer.com/blog/2022/05/08/different-types-of-pipettes/
• https://www.labcompare.com/General-Laboratory-Equipment/1265-Pipettes-Micropipettes/
• https://www.nichiryo.co.jp/en/productline/pipette.html
• https://www.brand.de/brand/contentserv_data/Context/BRAND%20GMBH%20%2B%20CO%20KG/Dokumente/Produkte/Application-Technical%20Notes/Application%20notes/Liquid%20Handling/Technical_Note_Luftpolsterpipette_Mehrfachdispenser_EN.pdf
• https://www.mrclab.com/a-guide-to-understanding-pipettes
• https://www.thermofisher.com/np/en/home/life-science/lab-plasticware-supplies/lab-plasticware-supplies-learning-center/lab-plasticware-supplies-resource-library/fundamentals-of-pipetting/liquid-handling-selection/pipette-types-for-different-applications.html
• https://www.ivdconsumablesupplier.com/news/classification-and-working-principle-of-pipett-47168674.html