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Glass Pipettes – Definition, Principle, Types, Handling, and Uses

What are Glass Pipettes?

  • Glass pipettes are essential tools in laboratory settings for their ability to transfer liquids with precision and control. They are primarily made from borosilicate glass, which is a durable and heat-resistant material that can withstand exposure to chemicals without breaking or corroding. The use of borosilicate glass ensures the reliability and longevity of glass pipettes.
  • These pipettes are available in various sizes, offering different capacities to accommodate different liquid volumes. They range from a few microliters to milliliters, allowing researchers to handle liquids accurately according to their experimental requirements.
  • Glass pipettes belong to a broader category of calibrated laboratory equipment designed for liquid handling. Other types of pipettes commonly used in laboratories include micropipettes, automated pipettes, and more. However, glass pipettes hold particular significance due to their precise measurement capabilities, especially when dealing with milliliter (ml) volumes.
  • Different types of glass pipettes exist, each suited for specific applications and experimental needs. When using glass pipettes, it is crucial to employ an attached filler, such as a pipette bulb or pipette filler, to facilitate the process of filling the pipette with liquids. This filler acts as a suction device, allowing the researcher to draw in the liquid into the pipette with ease and accuracy.
  • Glass pipettes find extensive use across various sectors and industries. They are indispensable tools in chemical laboratories, biochemistry laboratories, forensic science, and microbiology laboratories, among others. Their precision and reliability make them essential for tasks that require accurate liquid transfers, measurements, and mixing of substances in controlled environments.
  • Overall, glass pipettes play a vital role in laboratory settings, providing researchers with a dependable means of transferring liquids while maintaining the integrity of their experiments.

Features of Glass Pipettes

Glass pipettes possess several features that make them indispensable tools in laboratory settings. Here are some key features of glass pipettes:

  1. Accuracy and Precision: Glass pipettes are calibrated to deliver a specific volume of liquid, ensuring accurate and precise measurements. They allow researchers to transfer small amounts of liquid with a high degree of accuracy, which is crucial for many laboratory applications.
  2. Durability: Glass pipettes are crafted from high-quality borosilicate glass, renowned for its strength and resistance to breakage. This durability enables glass pipettes to withstand repeated use, making them reliable tools in laboratory environments.
  3. Chemical Inertness: Glass pipettes exhibit chemical inertness, meaning they do not react with the chemicals they come into contact with during experiments. This characteristic makes them ideal for use in various laboratory applications where it is essential to prevent contamination or chemical reactions between the pipette and the sample.
  4. Reusability: Glass pipettes are reusable tools, contributing to cost savings and waste reduction. After each use, they can be easily cleaned and sterilized, allowing for their repeated utilization over extended periods. This reusability feature makes glass pipettes an environmentally friendly choice.
  5. Variety: Glass pipettes are available in a range of sizes, offering different capacities for liquid handling. Their sizes span from a few microliters to several milliliters, enabling their use in a wide array of laboratory applications. This variety ensures that researchers can select the appropriate glass pipette based on their specific volume requirements.

In summary, glass pipettes combine accuracy, durability, chemical inertness, reusability, and versatility to meet the needs of laboratory professionals. With their precise liquid handling capabilities and resistance to breakage, glass pipettes are essential tools for performing experiments and transferring liquids in a controlled and efficient manner.

Working Principle of Glass Pipettes

The working principle of glass pipettes revolves around the concept of air displacement and capillary action. Here is an explanation of how glass pipettes function:

  1. Creation of Vacuum: The first step involves squeezing the pipette filler or bulb attached to the suction end of the pipette. This action creates a vacuum or negative pressure inside the pipette.
  2. Capillary Action: The vacuum created in the pipette causes the liquid to be drawn up into the pipette tip through capillary action. Capillary action refers to the movement of liquid within a narrow space, such as the fine opening of the pipette tip. The liquid is drawn upward against gravity due to adhesive forces between the liquid and the inner surface of the pipette.
  3. Liquid Holding: Once the liquid is drawn into the pipette, it is held in place by the vacuum. The pipette’s precise calibration ensures that the correct volume of liquid is captured and retained within the pipette tip.
  4. Dispensing: To dispense the liquid, the pressure on the pipette filler or bulb is released. This allows air to enter the pipette, breaking the vacuum. As a result, the liquid is forced out of the pipette tip, enabling controlled dispensing.

The volume of liquid drawn into the pipette depends on the capacity of the pipette, indicated by the markings on the stem. The user can select a pipette with the appropriate volume range for their specific liquid handling needs.

Glass pipettes offer accuracy, precision, and durability in their working principle. Their reusable nature provides cost-efficiency, although they require careful handling due to their fragility. Additionally, cleaning glass pipettes thoroughly is crucial to maintain their accuracy and prevent cross-contamination between different samples.

In summary, the working principle of glass pipettes relies on the creation of a vacuum by the pipette filler or bulb, which allows for the precise aspiration and dispensing of liquids through capillary action and air displacement.

Parts of Glass Pipettes

Glass pipettes consist of various parts that contribute to their functionality and ease of use. Here are the main parts of glass pipettes:

  1. Orifice of the Tip: The orifice refers to the pointed end of the pipette that directly comes into contact with the liquid being transferred. It allows for precise dispensing of the liquid.
  2. Calibration Details: Above the graduation mark on the pipette, there is an area that contains important information about the pipette’s calibration. This section includes details such as the manufacturer’s name, volume range (for measuring pipettes) or nominal volume (for bulb pipettes), tolerance volume, calibration temperature, standard used for calibration, and waiting time.
  3. Color Rings: Some companies use color rings or color bands as a coding system to identify the nominal volume of the pipette. These rings help users quickly recognize the capacity of the pipette.
  4. Suction End: The suction end is the upper part of the pipette where a pipette filler or bulb can be attached. This is where the suction is created to aspirate and dispense liquids.
  5. Tip: The tip of the pipette is the narrow end that is responsible for dispensing the liquid. It allows for precise delivery of the desired volume.
  6. Stem: The stem is the long and thin portion of the pipette that connects the suction end to the tip. It acts as a conduit for liquid transfer.
  7. Bulb: A rubber bulb is often used as a suction device to create the necessary suction pressure for aspirating liquids into the pipette. It is attached to the suction end and squeezed to control the liquid transfer.
  8. Rubber Washer: A small rubber washer is typically placed between the bulb and the suction end of the pipette. This washer helps create a seal and prevents liquid from leaking out during aspiration and dispensing.

In addition to these main parts, different types of glass pipettes may have additional features specific to their design and functionality. For example, a bulb pipette may include a volume mark for accurate pipetting of specific liquid volumes, while a blow-out or serological pipette may have a blow-out ring near the uppermost or suction part of the pipette.

These various parts work together to ensure precise liquid handling and accurate measurements when using glass pipettes in laboratory settings.

Types of Glass Pipettes

There are typically three varieties of glass pipettes: graduated, non-graduated, and Pasteur Glass Pipettes.

1. Graduated Glass pipettes

Graduated Glass pipettes
Graduated Glass pipettes
  • Graduated glass pipettes, also known as measuring pipettes, are a specific type of pipette that features increments marked along the length of the straight glass tube. These markings, typically in the form of calibrated lines, allow for accurate measurement and transfer of specific volumes of liquid.
  • The graduated markings on the glass pipette enable precise volume measurements. Each increment represents a specific volume, such as milliliters (ml) or microliters (µl), depending on the scale of the pipette. The user can align the desired volume with the liquid level by visually observing the position of the meniscus—the curved surface of the liquid in the pipette—to ensure accurate measurement.
  • Graduated glass pipettes are particularly useful when precise and adjustable volume transfers are required. They provide flexibility in dispensing various volumes by enabling the user to choose the appropriate graduated marking that matches the desired volume. This feature makes them valuable tools in laboratory settings where accurate and controlled liquid handling is critical.
  • These pipettes are commonly used in experiments, research, and analytical procedures that demand precise volume measurements. Graduated glass pipettes find applications in diverse scientific fields, including chemistry, biology, pharmaceuticals, and medical research.
  • It is important to note that while graduated glass pipettes facilitate volume measurements, they still require careful handling and technique to ensure accuracy. Proper alignment of the meniscus and consistent eye-level observation are essential for precise liquid transfers.
  • Overall, graduated glass pipettes are indispensable tools in laboratories, allowing scientists, researchers, and technicians to measure and transfer liquid volumes accurately, contributing to the success and reliability of their experiments and analyses.

Types of Graduated Glass pipettes

Graduated glass pipettes can be further classified into different types based on their graduation marks, nominal volume, construction, and accuracy. Here are some common types:

  1. Mohr’s Pipette: Mohr’s pipette, also known as a drain-out pipette, is a straight tube with graduation marks at each 0.1 ml interval. The first graduation mark starts well above the bottom of the pipette tip. It is important to prevent any breakage or damage to the tip, as it can affect the precision of liquid handling.
  2. Serological Pipette: Serological pipettes are blow-out pipettes. They feature a straight tube with a graduation mark near the tip. Slight pressing of the bulb at the end of dispensation is required for accurate delivery of the liquid.
Types of Graduated Glass pipettes
Types of Graduated Glass pipettes

In addition to the types based on graduation marks, graduated glass pipettes can also be categorized based on their construction and accuracy:

Types of Graduated Glass pipettes
  1. Type 1: Type 1 pipettes have nominal values at the bottom and can only deliver liquid samples partially for all the values.
  2. Type 2: Type 2 pipettes have nominal values at the top of the pipette and the highest value below it.
  3. Type 3: Similar to Type 1 in construction, Type 3 pipettes can deliver fluids completely only for the nominal value.
Types of Graduated Glass pipettes

When using type 1 or type 3 graduated pipettes (zero point at the top), the meniscus must:

  1. be set to the zero point and then the liquid must be drawn out to slightly exceed the desired volume fraction.
  2. Following a 5-second delay, the meniscus should be set a second time.

Working with type 2 graduated pipettes is considerably more efficient and straightforward. With type 1 and type 3 pipettes, there is a chance that the always-required second meniscus setting will discharge too much liquid, necessitating a redo of the sample preparation (the same is true for bulb pipettes with two marks).

Furthermore, graduated pipettes can be classified based on their accuracy:

  1. Class A: Class A graduated pipettes are highly accurate and have specified error ranges. They are designed for precise measurements and deliver reliable results.
  2. Class As: Class As pipettes are also highly accurate, similar to Class A. They meet the same stringent standards for precision and error limits.
  3. Class B: Class B graduated pipettes are less accurate compared to Class A and Class As pipettes. They have double the general error limits, making them suitable for general laboratory applications where high precision is not critical.

These different types of graduated glass pipettes provide scientists, researchers, and technicians with options to select the most suitable pipette based on their specific needs, accuracy requirements, and the nature of the experiment or procedure being performed.

2. Non-graduated pipettes

  • Non-graduated pipettes, also known as volumetric pipettes, bulb pipettes, or transfer pipettes, are a type of pipette that do not have graduation marks or increments along their tubes. These pipettes are specifically designed to deliver a fixed and accurate volume of liquid.
  • Unlike graduated pipettes that allow for adjustable volume measurements, non-graduated pipettes are calibrated to deliver a precise volume, typically indicated on the pipette itself or in the accompanying documentation. They are commonly available in various sizes, ranging from small microliter capacities to larger milliliter capacities.
  • Non-graduated pipettes are widely used when precise and consistent volume transfers are required, particularly in applications where accuracy is critical. They are often employed in analytical procedures, titrations, and other experiments that demand precise control over the volume of liquid being dispensed.
  • To use a non-graduated pipette, the user simply draws the liquid into the pipette using a suction device, such as a bulb or pipette filler, until the liquid level aligns with the specified volume marking. The liquid can then be accurately dispensed by releasing the pressure on the suction device.
  • These pipettes are typically made of glass or plastic and are designed for single-use or limited reuse. Proper handling and care should be exercised to maintain the accuracy and integrity of non-graduated pipettes.
  • Non-graduated pipettes offer a reliable and efficient solution for delivering precise volumes of liquid without the need for graduations or measurements along the tube. Their straightforward design and accuracy make them valuable tools in laboratory settings, ensuring consistent and controlled liquid transfers.

Steps on how to use a Non-graduated pipettes

Here are step-by-step instructions on how to use a non-graduated pipette:

  1. Gather your materials: Collect a non-graduated pipette, the liquid you wish to transfer, and a suitable container to receive the liquid.
  2. Immerse the tip: Submerge the tip of the pipette into the liquid. Ensure that the tip is fully immersed, but avoid touching the bottom of the container.
  3. Draw up the liquid: To draw the liquid into the pipette, you can either suck on the end of the pipette (with caution) or use a pipette filler designed for non-graduated pipettes. Apply gentle suction or squeeze the pipette filler to create a vacuum inside the pipette, allowing the liquid to be drawn up.
  4. Be cautious with the liquid level: Pay attention to the volume of liquid being drawn into the pipette. Avoid overfilling the pipette, as this can result in spillage and inaccurate measurements.
  5. Dispense the liquid: To dispense the liquid, release the pressure on the pipette or gently squeeze the pipette filler. Control the flow of liquid to ensure accurate and precise dispensing into the desired container.
  6. Clean and sterilize the pipette: After use, clean the non-graduated pipette thoroughly to prevent contamination. Follow appropriate cleaning protocols, such as washing with soap and water or utilizing sterilization methods recommended for your laboratory setting.

By following these steps, you can effectively and safely use a non-graduated pipette for transferring liquid volumes. Remember to exercise caution to avoid spills, handle the pipette with care, and properly clean the pipette after use to maintain accuracy and prevent cross-contamination.

Safety tips to keep in mind when using non-graduated pipettes

When using non-graduated pipettes, it is important to prioritize safety. Here are some key safety tips to keep in mind:

  1. Avoid excessive suction: Do not apply excessive suction force when drawing up the liquid into the pipette. Excessive suction can increase the risk of the pipette breaking, potentially causing injury or exposure to hazardous substances.
  2. Gentle dispensing: When dispensing the liquid, avoid forcefully expelling it from the pipette. Apply gentle pressure to the pipette or pipette filler to control the flow and prevent sudden release of liquid, which could cause the pipette to break.
  3. Clean and sterilize after use: Clean and sterilize the non-graduated pipette after each use to prevent cross-contamination and ensure the pipette is free from any residues or contaminants. Follow appropriate cleaning and sterilization protocols recommended by the manufacturer or your laboratory guidelines.
  4. Do not use your mouth for suction: Never use your mouth to create a vacuum or draw up liquid with non-graduated pipettes. This practice poses significant health risks, such as accidental ingestion of hazardous chemicals. Always use proper suction devices or pipette fillers designed for non-graduated pipettes.
  5. Handle with care: Non-graduated pipettes, like glass pipettes, can be fragile and break easily. Take precautions to avoid dropping or mishandling the pipette to prevent breakage and potential injuries. Handle the pipette with a gentle grip and store it securely when not in use.
  6. Proper disposal of broken pipettes: If a non-graduated pipette breaks, handle the broken pieces with care. Dispose of them in designated sharps containers to prevent injuries from sharp glass fragments.
  7. Personal protective equipment (PPE): Wear appropriate protective gloves and eye protection when working with non-graduated pipettes to protect against cuts and potential splashes.
  8. Work in a well-ventilated area: Ensure adequate ventilation in your workspace to minimize exposure to any fumes or vapors that may arise during pipetting procedures.
  9. Be aware of your surroundings: Maintain awareness of your surroundings while working with non-graduated pipettes. Ensure you have enough space to work safely and avoid potential accidents or collisions.
  10. Follow manufacturer’s instructions: Adhere to the manufacturer’s guidelines and instructions for cleaning, sterilizing, and handling non-graduated pipettes. This will help ensure proper usage and maintenance of the pipettes.

By following these safety tips, you can minimize risks and promote a safe working environment when using non-graduated pipettes in laboratory settings.

Use of Non-graduated pipettes

Non-graduated pipettes, also known as transfer pipettes or serological pipettes, find diverse applications in laboratory settings. Here are some common uses of non-graduated pipettes:

  1. Transferring small amounts of liquid between containers: Non-graduated pipettes are often employed to transfer precise volumes of liquid from one container to another. They allow for controlled and accurate transfer of small quantities, such as a few drops or milliliters of liquid.
  2. Adding reagents to solutions: Non-graduated pipettes are suitable for adding precise amounts of reagents to solutions during laboratory experiments or chemical analyses. Their controlled transfer capabilities aid in maintaining accurate proportions and ratios of reagents.
  3. Extracting samples: Non-graduated pipettes are commonly used to extract small samples for analysis or testing purposes. They enable controlled sampling of liquids or substances, making them valuable in fields such as biology, chemistry, and medicine.
  4. Diluting solutions: Non-graduated pipettes are effective in diluting solutions by adding precise amounts of solvents or diluents. They allow for accurate dilution and can be used in processes requiring precise concentration adjustments.
  5. Testing pH: Non-graduated pipettes are utilized for adding precise amounts of pH indicators to solutions. This enables pH testing or monitoring in various laboratory procedures and experiments.
  6. Carrying out chemical reactions: Non-graduated pipettes play a role in adding precise volumes of reagents to reaction mixtures. This ensures controlled initiation and progression of chemical reactions in a controlled manner.
  7. Plant tissue culture: Non-graduated pipettes are utilized in plant tissue culture for precise addition of nutrients, growth regulators, or other solutions to promote plant cell growth, propagation, or tissue culture experiments.
  8. Microbiology: Non-graduated pipettes find applications in microbiology for precise addition of microorganisms, such as bacteria or yeast, to culture media or for inoculation purposes. They facilitate controlled growth and experimentation with microorganisms.
  9. Biochemistry: In biochemistry, non-graduated pipettes are used for precise addition of biological molecules, enzymes, proteins, or substrates in various biochemical reactions or assays. They enable controlled and accurate manipulation of samples for analysis or experimentation.

Non-graduated pipettes provide a versatile and convenient means of transferring small liquid volumes in laboratory settings. While they may not offer the precision of graduated pipettes, they are still valuable tools in various applications. It is important to be aware of their limitations, such as lower accuracy and potential difficulty in cleaning, and select the appropriate pipette for each specific use.

Advantages of Non-graduated pipettes

Non-graduated pipettes offer several advantages in laboratory settings. Here are some key advantages:

  1. Versatility: Non-graduated pipettes are versatile tools suitable for various applications. They can be used for transferring liquids between containers, adding reagents to solutions, and extracting samples. This versatility allows them to be used in different laboratory disciplines, including biology, chemistry, medicine, and more.
  2. Ease of use: Non-graduated pipettes are designed for simple and straightforward use. Unlike graduated pipettes that require precise volume measurements, non-graduated pipettes are pre-calibrated to transfer a specific amount of liquid. This eliminates the need for additional measurements, making them user-friendly and particularly suitable for applications where high accuracy is not crucial.
  3. Cost-effectiveness: Non-graduated pipettes are relatively inexpensive compared to more sophisticated pipetting instruments. Their affordability makes them a practical choice, especially for laboratories operating on a budget. The cost-effectiveness of non-graduated pipettes allows for increased accessibility to essential liquid transfer tools.
  4. Disposable option: Non-graduated pipettes are often available as disposable pipettes. This disposability feature provides convenience and helps maintain a sanitary laboratory environment. Disposable pipettes eliminate the need for extensive cleaning and sterilization procedures, reducing the risk of cross-contamination between samples or solutions. They are particularly advantageous in applications where contamination control is critical.

Overall, the advantages of non-graduated pipettes lie in their versatility, ease of use, cost-effectiveness, and disposable nature. These factors contribute to their wide applicability in various laboratory settings, offering practical and convenient solutions for liquid transfer needs.

Disadvantages of Non-graduated pipettes

Non-graduated pipettes, while versatile in many laboratory applications, do have some disadvantages. Here are the key drawbacks to consider:

  1. Lower accuracy compared to graduated pipettes: Non-graduated pipettes are not as precise as graduated pipettes, resulting in slightly variable liquid transfer volumes. The accuracy of non-graduated pipettes can be compromised depending on factors such as the technique used and individual user variability. This limitation can pose challenges in applications that require a high degree of accuracy, such as quantitative analysis or precise measurements in research.
  2. Difficulty in cleaning: The cleaning process for non-graduated pipettes, particularly the narrow tip, can be challenging. When used with viscous liquids or substances, residue can accumulate and become trapped within the pipette. Inadequate cleaning may lead to cross-contamination between samples or potential inaccuracies in subsequent pipetting. Thorough and effective cleaning practices, including appropriate cleaning agents and techniques, are crucial to mitigate this disadvantage.
  3. Time-consuming for precise volume transfer: Non-graduated pipettes can be time-consuming when precise volumes of liquid need to be transferred. Achieving accurate volume transfer with non-graduated pipettes requires careful filling and emptying, as well as precise control of liquid flow. This can be more time-consuming compared to using graduated pipettes or automated pipetting systems, which offer greater precision and speed in volume transfer.

It’s important to consider these disadvantages when selecting the appropriate pipetting tool for specific applications. While non-graduated pipettes offer convenience and simplicity, their limitations in accuracy, cleaning, and time efficiency should be taken into account for tasks that demand higher precision or productivity.

3. Glass Pasteur pipettes

Glass Pasteur pipettes are specialized glass pipettes that are commonly used in laboratories to transfer small volumes of liquid. Here is some information about glass Pasteur pipettes:

  • Material: Glass Pasteur pipettes are typically made of borosilicate glass. This type of glass is known for its strength, durability, and resistance to chemicals, making it ideal for laboratory use.
  • Design: Pasteur pipettes feature a long, thin stem with a tapered tip. The tip is often fire-polished to create a smooth, rounded opening, facilitating controlled and precise liquid transfer.
  • Size and Capacity: Glass Pasteur pipettes come in various sizes, accommodating different volume requirements. They can handle volumes ranging from a few microliters to several milliliters, making them suitable for transferring small amounts of liquid in biology, chemistry, and other laboratory applications.
  • Accuracy and Precision: Glass Pasteur pipettes offer high accuracy and precision, enabling researchers to transfer small liquid volumes with great accuracy. They are calibrated to deliver specific volumes, ensuring precise measurements and reliable results.
  • Durability: Glass Pasteur pipettes are designed to be durable and withstand repeated use. The borosilicate glass construction enhances their resilience, making them reliable tools in laboratory settings.
  • Chemical Inertness: Glass Pasteur pipettes are chemically inert, meaning they do not react with the substances they come into contact with during experiments. This inertness ensures the integrity of the samples and prevents contamination.
  • Reusability: Glass Pasteur pipettes are reusable instruments, contributing to cost savings and waste reduction. They can be cleaned and sterilized after each use, allowing for their repeated utilization over an extended period.
  • Variety: Glass Pasteur pipettes are available in a range of sizes and capacities, allowing for versatility in laboratory applications. Their varied options cater to different liquid volume requirements and experimental needs.

Glass Pasteur pipettes are valuable tools in laboratories, enabling precise and controlled transfer of small liquid volumes. Their accuracy, durability, and chemical inertness make them indispensable in various scientific disciplines, including biology, chemistry, and research applications.

Steps on how to use a glass Pasteur pipette

Here are step-by-step instructions on how to use a glass Pasteur pipette:

  1. Gather your materials: Collect a glass Pasteur pipette, a pipette filler or bulb, and the liquid you want to transfer.
  2. Attach the pipette filler or bulb: Connect the pipette filler or bulb to the suction end of the pipette. Ensure it fits securely without damaging the pipette.
  3. Create a vacuum: Squeeze the pipette filler or bulb to create a vacuum in the pipette. Avoid excessive suction that may risk breaking the pipette.
  4. Immerse the tip: Submerge the tip of the pipette into the liquid. The tip should be fully immersed but not touching the bottom of the container.
  5. Release the pipette filler or bulb: Let go of the pipette filler or bulb, allowing the liquid to be drawn up into the pipette. The liquid will rise until the vacuum is broken.
  6. Break the vacuum: Use your finger to touch the blow-out ring, a small ring near the top of the pipette, to release the vacuum. This will enable dispensing of the liquid.
  7. Dispense the liquid: Gently squeeze the pipette filler or bulb to dispense the desired amount of liquid. Take care not to over-dispense to prevent spills or inaccurate measurements.
  8. Clean and sterilize: After use, clean the glass Pasteur pipette thoroughly to prevent contamination. Wash it with soap and water or follow appropriate cleaning protocols. Sterilize the pipette as required by autoclaving or other suitable methods.

By following these steps, you can effectively and accurately use a glass Pasteur pipette for transferring small amounts of liquid in laboratory settings.

Uses of Glass Pasteur pipettes

Glass Pasteur pipettes find numerous uses across various laboratory disciplines. Here are some key applications of Glass Pasteur pipettes:

  1. Transferring small amounts of liquid between containers: Glass Pasteur pipettes are commonly employed to transfer precise volumes of liquid from one container to another. This is particularly useful when diluting solutions, transferring samples, or moving small volumes for further analysis.
  2. Adding reagents to solutions: Glass Pasteur pipettes allow for precise and controlled addition of reagents to solutions. This is essential for initiating chemical reactions, adjusting pH levels, or introducing specific substances to achieve desired reactions or experimental conditions.
  3. Extracting samples: Glass Pasteur pipettes enable the extraction of small liquid samples from larger volumes or samples. This is beneficial in analytical procedures, where precise sampling is required for subsequent analysis or isolation of specific components.
  4. Diluting solutions: Glass Pasteur pipettes are valuable for diluting solutions by adding precise amounts of solvents or diluents. Dilution is often necessary to adjust concentrations, facilitate compatibility with other reagents, or prepare standard solutions.
  5. Testing pH: Glass Pasteur pipettes can be used to add precise volumes of pH indicators to solutions. This enables accurate pH testing and monitoring in various laboratory procedures and experiments.
  6. Carrying out chemical reactions: Glass Pasteur pipettes facilitate the controlled addition of precise reagent volumes to reaction vessels. This ensures accurate initiation or progression of chemical reactions, allowing for optimal control and analysis of reaction kinetics.
  7. Plant tissue culture: Glass Pasteur pipettes are employed in plant tissue culture for precise nutrient addition to cultures. This aids in promoting the growth of plant cells, tissues, or explants, facilitating successful tissue culture experiments.
  8. Microbiology: Glass Pasteur pipettes are utilized to add precise amounts of bacteria, yeast, or other microorganisms to culture media. This allows for controlled inoculation and growth of microorganisms, supporting microbiological studies, research, or testing the efficacy of antibiotics.
  9. Biochemistry: In biochemistry, Glass Pasteur pipettes are used for precise addition of proteins, enzymes, or other biological molecules to reactions. This enables controlled manipulation of samples for analysis, biochemical assays, or studying the properties of biomolecules.

Glass Pasteur pipettes offer versatility, precision, and ease of use across various laboratory applications. Their ability to transfer small volumes accurately makes them indispensable tools in research, analysis, and experimentation.

Disadvantages of glass Pasteur pipettes

Glass Pasteur pipettes, despite their usefulness, do have some disadvantages. Here are a few drawbacks associated with glass Pasteur pipettes:

  1. Fragility: Glass Pasteur pipettes are fragile and prone to breakage, especially if mishandled or accidentally dropped. Their delicate nature makes them more susceptible to damage, requiring careful handling to prevent breakage.
  2. Difficult to Clean: Cleaning glass Pasteur pipettes, particularly when used with viscous or sticky liquids, can be challenging. The narrow and elongated design of the pipettes makes it difficult to completely remove residue or trapped liquid, potentially leading to cross-contamination or inaccurate results.
  3. Time-Consuming: Using glass Pasteur pipettes can be time-consuming, especially when transferring small volumes of liquid. The process of carefully filling and emptying the pipette, as well as controlling the flow of liquid, can take more time compared to other liquid transfer methods. This can slow down laboratory procedures that involve numerous transfers or require precise timing.
  4. Potential Inaccuracy: Inaccuracies can arise when glass Pasteur pipettes are not filled or emptied properly. Inconsistent filling or inefficient emptying of the pipette can result in variations in the transferred volume, leading to inaccurate measurements. This can be problematic when precise and reliable results are crucial.

While glass Pasteur pipettes have these disadvantages, they remain widely used due to their suitability for specific applications and the availability of alternative pipette types that may address some of these concerns. It is important to handle glass Pasteur pipettes with care, follow proper cleaning protocols, and ensure proper technique to mitigate these drawbacks and optimize their performance in laboratory settings.

Safety tips for using glass Pasteur pipettes

When using glass Pasteur pipettes, it is important to prioritize safety. Here are some key safety tips to consider:

  1. Use the correct pipette filler or bulb: Ensure that you are using a pipette filler or bulb that is specifically designed for the size of the pipette being used. Using an ill-fitting or inappropriate filler/bulb can compromise the pipette’s integrity or make it difficult to create a vacuum.
  2. Avoid excessive suction: Do not apply excessive suction force when aspirating liquid into the pipette. Excessive suction can increase the risk of the pipette breaking, leading to potential injury or exposure to hazardous substances.
  3. Dispense liquid gently: When dispensing liquid from the pipette, avoid forcing it out forcefully. Apply gentle pressure on the pipette filler or bulb to control the flow and prevent sudden release of liquid, which could cause the pipette to break.
  4. Clean and sterilize after use: Clean and sterilize the glass Pasteur pipette after each use to prevent cross-contamination and ensure the pipette is free from any residues or contaminants. Follow appropriate cleaning protocols recommended by the manufacturer or your laboratory guidelines.
  5. Do not use your mouth for suction: Never use your mouth to create a vacuum or aspirate liquid with a glass Pasteur pipette. This practice poses significant health risks, such as accidental ingestion of hazardous chemicals. Always use a proper pipette filler or bulb to create suction.
  6. Handle with care: Glass pipettes, including Pasteur pipettes, are fragile and can break easily. Take precautions to avoid dropping or mishandling the pipette, as broken glass can cause injuries. Handle the pipette with a gentle grip and store it securely when not in use.
  7. Proper disposal of broken pipettes: If a glass Pasteur pipette breaks, handle the broken pieces with care. Dispose of them in designated sharps containers to prevent injuries from sharp glass fragments.
  8. Personal protective equipment (PPE): Wear appropriate protective gloves and eye protection when working with glass Pasteur pipettes to protect against cuts and potential splashes.
  9. Work in a well-ventilated area: Ensure adequate ventilation in your workspace to minimize exposure to any fumes or vapors that may arise during pipetting procedures.
  10. Be aware of your surroundings: Maintain awareness of your surroundings while working with glass Pasteur pipettes. Ensure you have enough space to work safely and avoid potential accidents or collisions.

Following these safety tips will help mitigate risks and ensure a safe working environment when using glass Pasteur pipettes in the laboratory.

4. Other Types of Glass Pipettes

A. Glass dropper pipette

  • A glass dropper pipette, also known as an eye dropper or serological pipette, is a versatile tool commonly used in laboratories to transfer small amounts of liquid. It consists of a glass tube with a long, thin stem and a tapered tip, which is usually fire-polished to ensure a smooth and rounded edge. The pipette utilizes a rubber bulb to create suction, drawing up the liquid into the pipette, and then the pressure on the bulb is released to dispense the liquid into a receiving container.
  • When using a glass dropper pipette, it is important to follow proper procedures. First, gather the necessary materials, including the glass dropper pipette, the liquid to be transferred, and a suitable container to receive the liquid. Next, immerse the tip of the pipette into the liquid, ensuring that it is fully submerged but not touching the container’s bottom. Squeeze the rubber bulb gently to create suction, which will draw up the desired amount of liquid into the pipette. Finally, release the pressure on the bulb to dispense the liquid into the receiving container. After use, the pipette should be cleaned and sterilized to prevent contamination.
  • To ensure safe and effective use of glass dropper pipettes, there are some important safety tips to keep in mind. First, avoid exerting excessive force when creating suction, as this could cause the pipette to break. Similarly, do not force the liquid out when dispensing, as it may lead to pipette breakage. Additionally, always clean and sterilize the pipette after each use to minimize the risk of contamination.
  • Glass dropper pipettes find applications in various laboratory tasks, including transferring small amounts of liquid between containers, adding reagents to solutions, extracting samples, diluting solutions, and testing pH levels. They are particularly useful when precise volumes of liquid need to be dispensed in laboratory procedures such as solution dilution, chemical reactions, pH adjustments, and sample analysis.
  • Glass dropper pipettes offer several advantages. They are easy to use, eliminating the need for volume measurement as they are designed to transfer specific amounts of liquid. This makes them convenient, especially for users less familiar with graduated pipettes. Additionally, glass dropper pipettes are relatively inexpensive compared to graduated pipettes, making them a cost-effective choice for applications that do not require high accuracy. They are also disposable, reducing the risk of contamination and promoting sanitation in laboratory settings. Furthermore, their versatility allows for use in a wide range of laboratory applications.
  • However, there are some disadvantages to consider when using glass dropper pipettes. They are not as accurate as graduated pipettes since the volume of liquid transferred can vary slightly depending on how the pipette is used. This can be problematic for applications that demand a high level of precision. Additionally, cleaning glass dropper pipettes can be challenging, especially when used with viscous liquids, potentially leading to contamination of the pipette and the samples it is used with. Finally, if precise volumes of liquid need to be transferred, using glass dropper pipettes can be time-consuming due to the careful filling and emptying required, as well as the need for precise control over liquid flow.
  • In summary, glass dropper pipettes are widely used in laboratories for their ease of use, relative affordability, disposability, and versatility. However, their lower accuracy compared to graduated pipettes and difficulties in cleaning should be taken into account when selecting the appropriate pipette for specific laboratory applications.

B. Glass bulb pipette

  • A glass bulb pipette, also known as a bulb pipette or pipette filler, is a type of pipette commonly used in laboratories for transferring small amounts of liquid. It is made of glass and features a long, thin stem with a bulb at the end. The bulb serves the purpose of creating a vacuum, which allows for the liquid to be drawn up into the pipette.
  • Glass bulb pipettes come in various sizes, catering to different capacities ranging from a few microliters to several milliliters. They find applications in laboratory settings, including the transfer of small volumes of liquid between containers, the addition of reagents to solutions, and the extraction of samples.
  • Using a glass bulb pipette is a straightforward process. First, the bulb is filled with air by squeezing it. Next, the tip of the pipette is placed into the liquid that needs to be transferred, and the bulb is released. The vacuum created draws the liquid into the pipette. To dispense the liquid, the bulb is simply squeezed again.
  • Glass bulb pipettes offer several advantages as a laboratory tool. They are easy to use since there is no need to measure the volume of liquid, as the pipette is designed to transfer a specific amount. This makes them a convenient option, especially for users who are less familiar with graduated pipettes. Additionally, glass bulb pipettes are relatively inexpensive compared to graduated pipettes, making them a cost-effective choice for applications that do not require high accuracy. Furthermore, they are disposable, reducing the risk of contamination and ensuring sanitation compared to reusable pipettes.
  • However, there are some disadvantages associated with glass bulb pipettes. They are not as accurate as graduated pipettes since the amount of liquid transferred can vary slightly depending on how the pipette is used. This limitation can be problematic for applications that demand a high degree of precision. Moreover, cleaning glass bulb pipettes can be challenging, particularly when used with viscous liquids. Difficulties in cleaning can result in the pipette and the samples it is used with becoming contaminated. Lastly, if precise volumes of liquid need to be transferred, using a glass bulb pipette can be time-consuming. This is due to the careful filling and emptying required, as well as the challenge of controlling the flow of liquid.
  • In conclusion, glass bulb pipettes offer advantages such as ease of use, affordability, disposability, and versatility in laboratory applications. However, their limitations in accuracy compared to graduated pipettes and difficulties in cleaning should be taken into account when selecting the appropriate pipette for specific laboratory tasks.
Glass bulb pipette
Glass bulb pipette

Handling of Glass Pipettes

While managing glass pipettes in the laboratory, one should never aspirate liquids through the mouth. For aspirating, a pipette bulb, rubber bulb, or filler is utilized.

Handling of Glass Pipettes
Handling of Glass Pipettes

Steps 1: Pipette Bulb

A pipette bulb, also known as a rubber bulb or pipette filler, is an essential tool used in laboratories to safely and accurately fill pipettes with liquid. It is typically made of rubber, providing a flexible and airtight seal when attached to the pipette.

There are different types of pipette bulbs available, including general-purpose bulbs, three-valve bulbs, and thumb wheel type fillers made of plastic. The selection of the appropriate bulb depends on the specific requirements and preferences of the user.

Pipette filler or pipette bulb
Pipette filler or pipette bulb

Here is a step-by-step guide on using a three-valve pipette bulb:

  1. Attach the pipette at the insertion part: Place the open end of the pipette onto the nozzle or insertion part of the pipette bulb. Ensure a secure fit to prevent any leaks or air entering the system.
  2. Release air from the pipette: Before aspirating the liquid, it is necessary to create a vacuum within the pipette. Press valve A and the bulb simultaneously to expel any air inside the pipette, ensuring a clear and empty space.
  3. Insert the pipette tip into the liquid container: Lower the tip of the pipette into the liquid container containing the desired liquid. Be cautious not to submerge the pipette too deep, as this can affect the accuracy of the measurement.
  4. Aspirate the liquid: While maintaining a firm grip on the pipette bulb, press the S valve located at the bottom of the bulb. This action creates a vacuum, causing the liquid to be drawn up into the pipette. Control the pressure on the bulb to aspirate the appropriate volume of liquid.
  5. Dispense the liquid: Carefully transfer the pipette tip to the desired container where the liquid needs to be dispensed. Press valve E on the bulb to release the liquid. Control the pressure on the bulb to ensure accurate and controlled dispensing of the liquid.

The use of a pipette bulb provides a convenient and efficient method for filling and dispensing liquid in pipettes. It helps to minimize the risk of contamination, ensures accurate volume measurements, and enhances user comfort and control during pipetting operations.

Steps 2: Filling the Liquid

Filling the liquid in a pipette requires careful attention to ensure accurate volume measurement and precise delivery. Here are the steps involved in filling the liquid:

  1. Fill the pipette with pipette filler: Attach the pipette filler, such as a pipette bulb or pipette filler device, to the suction end of the pipette. Gently squeeze the pipette filler and place it slightly above 5 mm of the desired volume mark on the pipette. This ensures that there is enough liquid in the pipette for accurate measurement.
  2. Adjust and bring the liquid to the graduated mark: Slowly release the pressure on the pipette filler to create a vacuum or suction in the pipette. This allows the liquid to be drawn up into the pipette. Carefully adjust the pressure on the pipette filler to bring the liquid level to the desired graduation mark on the pipette. The meniscus, the curved surface of the liquid, should align precisely with the graduation mark.
  3. Set the meniscus at the mark: For colorless liquids, such as water, the upper meniscus (the concave side of the meniscus) should be set exactly at the graduation mark. In the case of liquids with color or opacity, like certain solutions or samples, the lower meniscus (the convex side of the meniscus) should be set at the graduation mark. Ensure accurate alignment to achieve the desired volume.
  4. Remove excess liquid from the tip: After setting the meniscus at the graduation mark, carefully remove any excess liquid adhering to the outside of the pipette tip. Gently touch the tip to the inner wall of the container to remove the excess liquid without affecting the volume inside the pipette. This step ensures precise delivery of the intended volume.

By following these steps, you can effectively fill a pipette with the desired liquid, align the meniscus accurately, and remove excess liquid for precise measurements and delivery. It is crucial to maintain proper pipetting techniques and handle the pipette with care throughout the process to ensure accurate and reliable results in laboratory experiments and applications.

Steps 3: Dispensing the Liquid

Dispensing the liquid from a pipette is a critical step that requires precision and control to ensure accurate delivery of the intended volume. Here are the steps involved in dispensing the liquid:

  1. Place the tip of the pipette into the container: Lower the tip of the pipette into the container or receiving vessel where you want to dispense the liquid. Take care not to touch the sides of the container with the pipette tip, as this could cause contamination or affect the accuracy of the delivery.
  2. Press the filler to dispense all the liquid: Apply gentle pressure to the pipette filler or bulb to begin the dispensing process. This will release the liquid from the pipette tip into the container. Control the pressure on the filler to ensure a steady and controlled flow of the liquid.
  3. Wait for a few seconds when the liquid reaches the tip: Depending on the specific guidelines provided by the manufacturer or the procedure being followed, there may be a recommended wait time once the liquid reaches the tip of the pipette. This allows any remaining liquid in the tip to flow into the container and ensures accurate and complete dispensing.
  4. Draw the pipette upwards by touching the wall to dispense the remaining liquid: After the specified wait time, slowly withdraw the pipette from the container by gently touching the inside wall of the container. This action helps to dispense any remaining liquid adhering to the pipette tip. Avoid blowing out the remaining liquid, as this can introduce variability and affect the accuracy of the delivered volume.

By following these steps, you can effectively dispense the liquid from the pipette while minimizing the risk of contamination, ensuring complete delivery, and maintaining accuracy in your laboratory procedures or applications. It is important to handle the pipette with care, maintain proper technique, and adhere to the recommended wait times to achieve reliable and consistent results.

Where should glass slides pipettes and capillary tubes be disposed?

Glass slides, pipettes, and capillary tubes should be disposed of in designated sharps containers. Sharps containers are specifically designed to safely collect and contain sharp objects, such as glass items, to prevent injury and potential contamination. These containers are typically made of rigid, puncture-resistant material and have a secure lid to prevent accidental access.

It is important to follow proper disposal protocols and regulations specific to your location or institution. In many laboratory settings, there are designated areas or containers specifically for the disposal of sharps. These containers are usually labeled and clearly marked to ensure proper disposal practices.

Never dispose of glass slides, pipettes, or capillary tubes in regular trash bins or recycling containers, as this can pose a risk to waste management personnel and the environment. It is essential to handle and dispose of these items responsibly to maintain a safe laboratory environment and comply with waste management guidelines.

Uses of Glass Pipettes

Glass pipettes are widely used in various scientific fields due to their precise liquid handling capabilities. Here are some specific applications of glass pipettes in different laboratories:

  1. Chemistry laboratory: Glass pipettes are essential tools for transferring liquids during various chemical processes. They are particularly useful in volumetric analysis, where accurate measurements of liquid volumes are crucial for carrying out experiments and tests.
  2. Pharmaceutical industry: Glass pipettes play a critical role in the pharmaceutical industry. They are used for transferring precise volumes of liquids during drug production and quality control processes. Glass pipettes ensure accurate dosing and formulation of pharmaceutical products.
  3. Microbiology laboratory: Glass pipettes are commonly used in microbiology laboratories for transferring different chemicals and reagents in milliliter (ml) quantities. They are utilized in various experiments, such as inoculating cultures, adding reagents, and performing dilutions.
  4. Biochemistry laboratory: Glass pipettes find extensive use in biochemistry laboratories for a range of tasks, including:
  • Preparation of buffer solutions: Buffer solutions are crucial for maintaining the pH of biochemical reactions. Glass pipettes are used to accurately measure and transfer the components needed for preparing buffer solutions.
  • Transfer of solutions for biochemical tests: Glass pipettes are used to transfer solutions during various biochemical tests, such as enzyme assays, DNA analysis, and protein quantification. The precise volume measurements provided by glass pipettes ensure reliable and reproducible results.
  • Accurate measurements of chemicals: Glass pipettes enable precise measurements of chemicals, allowing researchers to control and monitor the quantities of substances used in biochemical experiments. This is essential for maintaining experimental accuracy and consistency.

The use of glass pipettes extends beyond these specific fields, as they are versatile tools that find application in a wide range of scientific disciplines. Their accuracy, precision, and reliability make them indispensable in laboratory settings, where precise liquid handling is critical for accurate results and experimental success.

Advantages of Glass Pipettes

Glass pipettes offer several advantages in laboratory settings. Here are the main advantages highlighted from the provided information:

  1. Accuracy and precision: Glass pipettes are calibrated to deliver specific volumes of liquid, ensuring accurate and precise measurements. They are capable of transferring small amounts of liquid with great accuracy, making them suitable for applications where precise volumes are crucial, such as biochemical assays and clinical diagnostics.
  2. Durability: Glass pipettes are made of borosilicate glass, known for its strength and resistance to breakage. This durability allows glass pipettes to withstand repeated use, making them a reliable choice for laboratories. They can endure exposure to harsh chemicals and solvents, enhancing their longevity and usability.
  3. Chemical inertness: Glass pipettes are chemically inert, meaning they do not react with the liquids they come into contact with. This characteristic is essential for applications requiring the preservation of liquid purity. Glass pipettes are suitable for transferring sensitive liquids that may undergo undesired reactions or contamination with reactive materials.
  4. Reusability: Glass pipettes can be cleaned, sterilized, and reused, offering cost savings and sustainability benefits. After each use, they can be thoroughly cleaned to remove any residue and sterilized to ensure their suitability for subsequent applications. This reusability makes glass pipettes a cost-effective option in laboratories where regular and repetitive use is common.
  5. Low cost: Glass pipettes are relatively inexpensive compared to other types of pipettes, making them an economical choice for laboratories. This affordability allows laboratories to acquire a sufficient number of glass pipettes without incurring significant expenses. It is particularly advantageous for applications where high precision is not a critical requirement.

Overall, the accuracy, durability, chemical inertness, reusability, and low cost of glass pipettes make them a versatile and practical tool in laboratory environments, catering to a wide range of applications and experimental needs.

Disadvantages of Glass Pipettes

Glass pipettes, despite their advantages, have a few disadvantages that should be considered. Here are the main disadvantages based on the provided information:

  1. Fragile: Glass pipettes are fragile and susceptible to breakage, especially if mishandled or dropped. Their delicate nature requires careful handling to prevent accidents and damage. Laboratories with high activity levels or where pipettes are frequently shared among multiple users may face challenges in maintaining the integrity of glass pipettes.
  2. Difficult to clean: Glass pipettes can be challenging to clean, particularly when used with viscous liquids. The nature of these liquids can cause them to get trapped within the pipette, making thorough cleaning and removal of residue difficult. This can be a concern in applications where maintaining liquid purity is crucial, as residual substances may lead to contamination or inaccurate results.
  3. Time-consuming to use: Using glass pipettes can be time-consuming, especially when transferring small amounts of liquid. The precise filling and emptying of the pipette require careful attention, and controlling the flow of liquid can be challenging. This can become a drawback in applications that demand speed and efficiency, such as high-throughput screening or time-sensitive experiments.
  4. Contamination risk: If glass pipettes are not adequately cleaned and sterilized after each use, there is a risk of contamination. Bacteria or other microorganisms can adhere to the pipette’s surface, leading to cross-contamination between samples. Proper cleaning and sterilization protocols are crucial to avoid compromising experimental integrity and accuracy, particularly in environments where infection control is critical, such as clinical laboratories.

While glass pipettes possess several advantages, it is important to be mindful of their fragility, cleaning challenges, time-consuming nature, and potential contamination risks. By taking necessary precautions and implementing appropriate cleaning and sterilization practices, these disadvantages can be minimized, allowing for effective and reliable use of glass pipettes in laboratory settings.

FAQ

What are glass pipettes used for?

Glass pipettes are used for accurately measuring and transferring liquid volumes in laboratory settings. They are commonly employed in various scientific procedures, such as solution preparation, sample analysis, and reagent addition.

What types of glass pipettes are available?

There are several types of glass pipettes, including volumetric pipettes, graduated pipettes, Pasteur pipettes, serological pipettes, Mohr pipettes, and volumetric transfer pipettes. Each type has its own specific design and purpose.

How do I choose the right glass pipette for my application?

The choice of glass pipette depends on factors such as the required volume range, accuracy needed, and the specific task at hand. Volumetric pipettes are best for precise measurements, graduated pipettes for approximate measurements, and serological pipettes for general liquid transfers.

How accurate are glass pipettes?

The accuracy of glass pipettes varies depending on the type and quality. Volumetric pipettes generally offer the highest accuracy, with tolerances specified by the manufacturer. Graduated pipettes and serological pipettes have lower accuracy due to their design.

How do I calibrate a glass pipette?

Calibration of glass pipettes should be performed regularly using a calibrated balance or other suitable measuring equipment. Manufacturers often provide guidelines and procedures for calibration to ensure accurate volume transfer.

Can glass pipettes be autoclaved or sterilized?

Glass pipettes can typically withstand sterilization methods such as autoclaving, as they are made of heat-resistant glass. However, it’s important to follow the manufacturer’s instructions to prevent damage or breakage.

Are glass pipettes reusable?

Yes, glass pipettes are generally reusable. However, they require proper cleaning and sterilization between uses to prevent cross-contamination. It’s important to inspect the pipettes for any signs of damage or wear that could affect their accuracy.

How should I clean glass pipettes?

Glass pipettes can be cleaned by rinsing with an appropriate solvent or detergent followed by thorough rinsing with distilled water. Additionally, pipette brushes or specialized cleaning devices can be used to remove any residue from the interior walls.

Can I use glass pipettes with corrosive or viscous liquids?

Glass pipettes are generally compatible with a wide range of liquids, including corrosive substances. However, it’s important to check the chemical resistance of the glass and consider using appropriate protective measures when working with hazardous materials.

How should I store glass pipettes?

Glass pipettes should be stored in a clean, dry environment to prevent contamination or damage. Vertical pipette holders or racks are commonly used to store pipettes upright, protecting the tips and ensuring proper air circulation.

References

  • https://www.homesciencetools.com/content/reference/CE-PIPFILL.pdf
  • https://resources.saylor.org/wwwresources/archived/site/wp-content/uploads/2012/07/Chapter211.pdf
  • http://beta-static.fishersci.com/content/dam/fishersci/en_EU/suppliers/Brand_in_Wertheim/PDFs/Volumetric/Brochuere_Volumenmessung_EN.pdf
  • https://www.borosil.com/site/assets/files/1426/019_pipettes_page_150-161.pdf

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What is Karyotyping? What are the scope of Microbiology? What is DNA Library? What is Simple Staining? What is Negative Staining? What is Western Blot? What are Transgenic Plants? Breakthrough Discovery: Crystal Cells in Fruit Flies Key to Oxygen Transport What is Northern Blotting? What is Southern Blotting?
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