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Air-displacement or positive-displacement pipette? Find the right BRAND pipetting system for your application

Selecting the correct liquid handling device based on the medium used, the delivery volume, and the frequency of delivery is essential for precise and reliable work. The device must also provide optimum support for the application and contribute to efficiency in the laboratory. 

 

BRAND provides various air displacement pipettes and repetitive pipettes, including the Transferpette®, HandyStep®, and Transferpettor product lines. In this extended edition of the BRAND Pipette Basics, you will learn about the key differences between these two pipetting principles.

What is the difference between air-displacement and positive-displacement pipettes?

The key difference lies in how the force from the piston is transferred to the liquid:

The air displacement principle

Micropipette diagram showing labeled components—piston, pipetting shaft, disposable tip, air cushion, and reagent.

The air displacement principle is used mainly for pipettes and enables precise dispensing with fast and easy handling. By moving the piston in the pipette shaft up and down, a negative or positive pressure is created. This causes liquid to be aspirated into or expelled from the tip. However, the liquid is always separated from the inner piston and the pipette shaft by an air cushion and does not come into contact with the pipette itself when handled correctly. This enables contamination-free yet simple handling with the highest precision. But this is also where the application limits of the system lie. Media that strongly influence the air cushion can affect the accuracy of the result. For example, liquids with high viscosity or highly volatile media make precise work difficult. In these cases, the techniques described here and the temporary User Adjustment feature of the Transferpette® pro can help improve results.

The positive displacement principle

Schematic illustration of a positive displacement pipette showing the glass capillary, piston, and aspirated reagent.

The positive displacement principle is often used for repetitive pipettes or specialized positive displacement pipettes. In contrast to air displacement systems, the piston of the positive displacement pipette is in direct contact with the liquid to be pipetted. The piston aspirates the liquid through a vacuum and wipes the walls of the tip clean during dispensing – down to the last drop, which clearly leaves the tip. This principle ensures highly reproducible results regardless of the liquid and the influence of an air cushion. The piston, which is built into the device in air displacement models, is located in the tip cylinder in positive displacement models and must always be replaced in order to ensure contamination-free operation. Depending on the model, this can result in more time needed to change the tip and higher consumable costs. 

Advantages and Limits

Working principle

Vorteile

Grenzen

Vorteile

Easy and quick exchange of pipette tips

 

Fast serial pipetting of long test series

Grenzen

Pipetting of problematic solutions (high viscosity, highly volatile, high density or foaming) limited

 

Air cushion depends on many factors

Vorteile Suitable for problematic solutions (high viscosity, highly volatile, high density, or foaming)
Grenzen

Replacing the tip can be time-consuming

 

Higher costs for tips

With this technical background in mind, and considering the advantages and limitations of both systems, the next step is to select the right instrument for the user.

 

BRAND's large portfolio makes it possible to provide the right device for every user, both for positive displacement pipettes and for air displacement pipettes.

Air-displacement pipettes from BRAND

With the Transferpette® range, BRAND offers manual and electronic air-displacement pipettes for a wide variety of applications and volume ranges.

The Transferpette® S and Transferpette® pro enable true one-handed operation. The single-channel models cover volumes from 0.1 µl to 10 ml. For microplates, PCR plates, and deep-well plates, the 8- and 12-channel pipettes cover a volume range from 0.5 µl to 300 µl (Transferpette® S) or up to 1250 µl (Transferpette® pro).

The Transferpette® electronic also offers functions such as mixing, reverse pipetting, and dispensing, making it particularly suitable for repetitive pipetting tasks.

Transferpette® pro, 20-200 µl, adjustable volume, D-200, DE-M

Transferpette® pro, 20-200 µl, adjustable volume, D-200, DE-M

The Transferpette® pro micropipette allows you to work precisely, ergonomically, and flexibly – just as your daily lab routine demands!  Its slim design and adjustable finger rest ensure that the pipette fits perfectly in your hand, making it ergonomic and comfortable to use, even during long pipetting sessions.  To keep you flexible at all times, the Transferpette® pro features two adjustment techniques: Easy Calibration for permanent calibration without tools. And User Adjustment for quick, reversible adaptation to changing conditions such as temperature, tip shape, or media properties.  The Transferpette® pro is made of high-quality materials with built-in counter protection, making it both robust and durable. It's fully autoclavable (121 °C) and available as single and multi-channel pipettes.  Carbon Footprint information available at www.brand.de/pcf Limitations of use: Operating temperature should be between +15 °C and +40 °C (59 °F to 104 °F). Other temperatures upon request. Vapor pressure up to 500 mbar Viscosity: 260 mPa s For viscous media, the speed must be adjusted if necessary.

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Transferpette® S, 2-20 µl, adjustable volume, D-20, DE-M

Transferpette® S, 2-20 µl, adjustable volume, D-20, DE-M

The Transferpette® S air displacement pipette allows you to work efficiently and ergonomically with both small and large volumes. Low operating forces and a short stroke ensure relaxed pipetting, even during long pipetting series. Due to its perfect ergonomics, the Transferpette® S provides a comfortable grip in any hand position, whether you are right- or left-handed, or have big or small hands. Changing your grip is not necessary, since the microliter pipette provides true one-hand operation: set the volume, pipette, eject the tip.The volume-change protection is also easy to operate with gloves on and protects your set volume against accidental adjustment. The Transferpette® S also features Easy Calibration technology, which makes calibration a breeze. Calibration can be carried out without tools. A compatibility table shows which tips fit which device, so that you always order the correct pipette tips.Limitations of use: Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request) Vapor pressure up to 500 mbar Viscosity: 260 mPa s For viscous media, the speed must be adjusted if necessary.

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Transferpette® pro -12, 50-1250 µl, adjustable volume, M12-1250, DE-M

Transferpette® pro -12, 50-1250 µl, adjustable volume, M12-1250, DE-M

The Transferpette® pro micropipette allows you to work precisely, ergonomically, and flexibly – just as your daily lab routine demands!  Its slim design and adjustable finger rest ensure that the pipette fits perfectly in your hand, making it ergonomic and comfortable to use, even during long pipetting sessions.  To keep you flexible at all times, the Transferpette® pro features two adjustment techniques: Easy Calibration for permanent calibration without tools. And User Adjustment for quick, reversible adaptation to changing conditions such as temperature, tip shape, or media properties.  The Transferpette® pro is made of high-quality materials with built-in counter protection, making it both robust and durable. It's fully autoclavable (121 °C) and available as single and multi-channel pipettes.  Carbon Footprint information available at www.brand.de/pcf Limitations of use: Operating temperature should be between +15 °C and +40 °C (59 °F to 104 °F). Other temperatures upon request. Vapor pressure up to 500 mbar Viscosity: 260 mPa s For viscous media, the speed must be adjusted if necessary.

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Transferpette® S -8, 30-300 µl, adjustable volume, M8-300, DE-M

Transferpette® S -8, 30-300 µl, adjustable volume, M8-300, DE-M

The Transferpette® S air displacement pipette allows you to work efficiently and ergonomically with both small and large volumes. Low operating forces and a short stroke ensure relaxed pipetting, even during long pipetting series. Due to its perfect ergonomics, the Transferpette® S provides a comfortable grip in any hand position, whether you are right- or left-handed, or have big or small hands. Changing your grip is not necessary, since the microliter pipette provides true one-hand operation: set the volume, pipette, eject the tip.The volume-change protection is also easy to operate with gloves on and protects your set volume against accidental adjustment. The Transferpette® S also features Easy Calibration technology, which makes calibration a breeze. Calibration can be carried out without tools. A compatibility table shows which tips fit which device, so that you always order the correct pipette tips.Limitations of use: Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request) Vapor pressure up to 500 mbar Viscosity: 260 mPa s For viscous media, the speed must be adjusted if necessary.

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Transferpette® electronic, DE-M, 10-200 µl, power adapter Europe (100-240V/50-60Hz)

Transferpette® electronic, DE-M, 10-200 µl, power adapter Europe (100-240V/50-60Hz)

Transferpette® electronic pipettes combines the globally proven properties of mechanical piston operated air displacement pipettes by BRAND with the advantages of an electronic device.Features:The pipette shaft can be unscrewed and is entirely autoclavable (121 °C).Five convenient programs: pipetting, reverse pipetting, mixing, GEL-Electrophoresis and dispensing.Easy Calibration-Technique for making quick adjustments of the Transferpette® electronic, without tools.Limitations of use:Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request)Vapor pressure up to 500 mbarViscosity: 260 mPa sFor viscous media, the speed must be adjusted if

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Positive-displacement pipettes from BRAND

With the HandyStep® touch, HandyStep® S, and Transferpettor, BRAND offers a range of positive-displacement systems for challenging liquids and repetitive dispensing.

The HandyStep® models are particularly suitable for quickly dispensing long series as well as for handling viscous, volatile, or foaming liquids. The HandyStep® touch is operated electronically via a touchscreen, while the HandyStep® S is entirely mechanical.

The Transferpettor is a positive-displacement pipette designed for liquids that are difficult to pipette, such as highly viscous, foaming, or volatile liquids.

 

HandyStep® touch, DE-M, inclusive universal AC adapter and  shelf/rack mount

HandyStep® touch, DE-M, inclusive universal AC adapter and shelf/rack mount

Repetitive pipettes are the first choice when it comes to efficient dispensing of long series. Positive displacement pipettes are often the right solution for pipetting viscous media. The new stepper HandyStep® touch from BRAND combines both features. With the touchscreen display, you conveniently swipe back and forth between functions and always have an overview of the essential information on your work steps. Operation is easy, even with protective gloves on. And speaking of easy, the days of manually changing tips are over. On the HandyStep® touch, lightly tapping on the Eject icon on the display is enough to eject the tip. The HandyStep® touch repetitive pipette automatically recognizes the volume of the new BRAND PD- Tips II. This saves time and reduces the risk of error. Tips from many other manufacturers can also be used, providing maximum flexibility. Charging is easy and efficient: simply place the HandyStep® touch in the inductive charging stand and the battery automatically starts charging. Overview - Touchscreen operation with intuitive menu navigation in English, German, Spanish, French and Chinese - HandyStep® touch with the features multi-dispensing, auto-dispensing and pipetting; HandyStep® touch S with the additional features sequential dispensing, multi-aspiration and titration - Automatic size detection of BRAND PD-Tips II - Compatible with PD-Tips prior to the PD-Tips II generation and with tips from many other manufacturers: for example, Encode™ tips, Repet-Tips®, Combitips®, Combitips® plus, Combitips® advanced (the above-mentioned brands are property of their respective owners) - Automatic tip ejection - Variable volume adjustment from 1.0 μl to 50 ml - Easy to clean thanks to smooth surface without grooves and edges - Inductively rechargeable Limitations of use: Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request) Vapor pressure up to 500 mbar Viscosity: At 50 ml PD-Tip: 20 mPa s; at 5 ml PD-Tip: 260 mPa s; at 1,25 ml PD-Tip: 977 mPa

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HandyStep® touch S, DE-M, inclusive universal AC adapter and  shelf/rack mount

HandyStep® touch S, DE-M, inclusive universal AC adapter and shelf/rack mount

Repetitive pipettes are the first choice when it comes to efficient dispensing of long series. Positive displacement pipettes are often the right solution for pipetting viscous media. The new stepper HandyStep® touch from BRAND combines both features. With the touchscreen display, you conveniently swipe back and forth between functions and always have an overview of the essential information on your work steps. Operation is easy, even with protective gloves on. And speaking of easy, the days of manually changing tips are over. On the HandyStep® touch, lightly tapping on the Eject icon on the display is enough to eject the tip. The HandyStep® touch repetitive pipette automatically recognizes the volume of the new BRAND PD- Tips II. This saves time and reduces the risk of error. Tips from many other manufacturers can also be used, providing maximum flexibility. Charging is easy and efficient: simply place the HandyStep® touch in the inductive charging stand and the battery automatically starts charging. Overview - Touchscreen operation with intuitive menu navigation in English, German, Spanish, French and Chinese - HandyStep® touch with the features multi-dispensing, auto-dispensing and pipetting; HandyStep® touch S with the additional features sequential dispensing, multi-aspiration and titration - Automatic size detection of BRAND PD-Tips II - Compatible with PD-Tips prior to the PD-Tips II generation and with tips from many other manufacturers: for example, Encode™ tips, Repet-Tips®, Combitips®, Combitips® plus, Combitips® advanced (the above-mentioned brands are property of their respective owners) - Automatic tip ejection - Variable volume adjustment from 1.0 μl to 50 ml - Easy to clean thanks to smooth surface without grooves and edges - Inductively rechargeable Limitations of use: Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request) Vapor pressure up to 500 mbar Viscosity: At 50 ml PD-Tip: 20 mPa s; at 5 ml PD-Tip: 260 mPa s; at 1,25 ml PD-Tip: 977 mPa

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Repetitive pipette HandyStep® S

Repetitive pipette HandyStep® S

HandyStep® S – the repetitive pipette for so many applications! Ideal for routine or research applications in diagnostics, molecular biology, environmental analysis, and many more.HandyStep® S and PD-tips work on the direct displacement principle. This offers the highest-precision dispensing of liquid media with high viscosity, high density, or high vapor pressure. Direct displacement permits contamination-free operation, since no aerosols are formed. More data and facts: increased chemical resistance through innovative plastic materials easy tip mounting – PD-tip is now simply inserted from below dispensed volume range from 2 µl to 5 ml up to 49 dispensing steps weighs only 108 g suitable for use with BRAND PD-tips, Encode™ tips, Repet tips, Combitips®, Combitips® plus and other compatible dispenser tips. Limitations of use: Operating temperature of instrument and reagent should be between +15 °C and +40 °C (59 °F to 104 °F) (other temperatures upon request) Vapor pressure up to 500 mbar Viscosity: At 50 ml PD-Tip: 20 mPa s; at 5 ml PD-Tip: 260 mPa s; at 1,25 ml PD-Tip: 977 mPa

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Transferpettor Digital type, 2.5- 10 µl, with glass capillaries

Transferpettor Digital type, 2.5- 10 µl, with glass capillaries

The Transferpettor® delivers high-precision pipetting of viscous, foaming, and high vapor pressure liquids—ideal when air-displacement pipettes reach their limits. Based on the positive displacement principle, the piston is in direct contact with the aspirated liquid and fits tightly to wipe the tip walls clean, virtually to the last drop. This ensures reproducible results and negligible residual wetting, so tips don’t need to be discarded after each pipetting step. Areas of application Foaming media (e.g., surfactant solutions) High vapor pressure liquids (up to 500 mbar; e.g., alcohols, ether, hydrocarbons) Highly viscous media (up to 140,000 mm²/s, volume-dependent, see exclusion limits in manual) High-density media with up to 13.6 g/cm³ (macro, PP caps) or 3,8 g/cm³  (micro, glass capillaries)For Transferpettor® micro with glass capillaries, the Repair Set is recommended as additional equipment for maintenance to replace the piston rod and seal. Alternatively, the device can be sent to our technical service for repair. Limitations of use: Density up to 13.65 g/cm³ (macro, PP caps) or 3.8 g/cm³ (micro, glass capillaries) Vapor pressure up to 500 mbar Kinematic viscosity up to: Nominal volume 1/ 2/ 5 µl: 6.000 mm² /s; nominal volume 10 µl: 20.000 mm² /s; nominal volume 25 µl: 50.000 mm² /s; nominal volume 50 µl: 100.000 mm² /s; nominal volume 100 µl: 140.000 mm² /s (Operating temperature: 15 - 40 °C (59 °F - 104

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Still unsure which model is right for your application?

Or have you already found your favorite and would like to test the instrument first?

Request your BRAND demo unit here.

 

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Dr. Debora Reinhardt
Product Manager for Pipetting Devices

Dr. Debora Reinhardt is a Product Manager for Pipetting Devices at BRAND GMBH + CO KG in Wertheim, Germany. She studied biochemistry at the University of Würzburg and earned her PhD at the Institute of Pharmacy and Food Chemistry. During her academic research, pipetting was an integral part of her daily work. Today, she uses her practical experience to align pipettes with the requirements of modern laboratories in her role as a product manager.

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Otto-Schott-Str. 25
97877 Wertheim
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By submitting the contact form, you agree that your data will be used to process your request. If your inquiry originates from a country where we do not have our own sales department, you also consent to the forwarding of your data to the responsible local sales partner. You can find an overview of our sales partners on our contact page. Further information on data processing, including possible transfers to third countries, can be found in our privacy statement.

Fields marked with * are required.