From high schools and universities to state-of-the-art research centers, pipettes are a staple in laboratories around the world. These small but very functional instruments come in a variety of sizes, designs and capacities, using different pipettes depending on the application. Below, we look at best practice techniques for how to use pipettes in the lab. We also cover some important pipette facts, including the history of the instrument, the types of pipette models, and the use of pipette lab instruments.
pipette
What is a laboratory pipette?
Laboratory pipettes are specialized tools that allow scientists to deliver liquids safely and accurately. Commonly used in biology, chemistry, and medical laboratories, this piston-driven instrument is similar to a syringe and comes in many different designs, from basic single-piece glass pipettes to sophisticated electronic pipettes. The accuracy and precision of different designs vary widely, and laboratories choose pipettes based on their unique needs. Some pipettes are manually operated, while others use automated techniques.
How do laboratory pipettes work?
Most laboratory pipettes use an air vacuum over the liquid holding chamber to aspirate and release liquids. This air displacement is designed for use with both manual and electric pipettes and can be seen inserting the tip directly below the surface of the liquid. The pressure on the plunger is then released, drawing fluid into the tip. To release the fluid, pressure is applied to the plunger, forcing the fluid back down the chamber and out of the tip.
History of Laboratory Pipettes
While the pipette concept has been around for over a century, the first micropipette was not patented until 1957. It was developed by German scientist Dr. Heinrich Schnitger, founder of the industry-leading laboratory instrument manufacturer Eppendorf. Schnitger began commercial production in 1961, and micropipettes quickly became popular in laboratories around the world.
American inventor Warren Gilson and biochemistry professor Henry Lardy are also credited with developing adjustable micropipettes. Adjustable micropipettes are available in different size and volume combinations for added laboratory flexibility.
Micro and Large Pipettes
Micropipettes are designed with precision in mind, enabling scientists to accurately extract, transport and dispense liquids in the microliter range. Micropipette volumes range from 1 to 1000 microliters. Micropipettes are designed for large batches with volumes ranging from 0.25–5 mL.
Laboratory Pipette Types
Over the decades, manufacturers have developed a variety of different pipettes for special applications. Pipettes today come in countless designs, and the precision and accuracy of different models vary widely. Below, we've listed some of the most common pipettes in the lab.
single channel pipette
Single channel pipettes, also known as variable volume air displacement pipettes, are versatile and can be used in a variety of applications. Most offer a wide volume range between 0 and 2500 microliters. Depending on the application, scientists may choose to use adjustable fixed-volume single-channel pipettes.
The small and compact nature of single-channel pipettes means they are ideal for use in small source and destination vessels, such as conical tubes and clamshell vessels. Not only are single-channel pipettes compact enough for small containers, they also work well with wells and well plates.
High-quality single-channel pipettes are not only efficient but also ergonomic, designed to make the user experience as intuitive and comfortable as possible. This helps minimize the risk of repetitive strain injuries and increases accuracy and precision.
Although compact and easy to use, single-channel pipettes can only be used to transfer one liquid sample at a time. This means that using them can be tedious and time-consuming when multiple transfers are required.
multichannel pipette
Multichannel pipettes are ideal for microplate applications and are ideal for small-scale applications and repetitive tasks. Most feature between 8 and 12 heads, allowing scientists to transfer multiple liquid samples using a single device.
Productivity is one of the main advantages of multi-channel pipettes, and the technology significantly reduces the number of individual transfers required. They are often favored by scientists working on polymerase chain reaction (PCR), enzyme-linked immunosorbent assays (ELISA), and cell culture research.
While multichannel pipettes do reduce the number of individual transfers required, they still cause hand fatigue. For this reason, many multichannel pipettes have spring-loaded tips to reduce hand pressure, minimize the risk of repetitive strain injury and enhance pipette functionality in the laboratory.
electric pipette
Repetitive strain injury is one of the most common risks encountered by laboratory scientists. Electronic pipettes minimise the risk of injury through an automatic venting process. Electronic pipettes with internal motors provide the same accuracy and precision as manual pipettes, but without the physical strain. Electronic pipettes are especially useful when dispensing multiple times, a process that involves dividing reagents into different doses.
For example, scientists transferring PCR master mixes to 96-well plates will benefit greatly from using electronic pipettes. Using a manual pipette requires 96 separate transfers, which would result in significant ergonomic stress. In contrast, electronic pipettes can reduce transfer times by 30% or more, depending on tip size and volume of liquid transferred. In addition to saving time, using electronic pipettes also minimizes the risk of hand injury and fatigue.
Air displacement rate and dispersion are regulated using an internal motor, which helps reduce barrel contamination and prevents air bubbles from forming. They can be pre-programmed to suit specific laboratory tasks, increasing efficiency. Electronic pipettes also offer adjustable tip spacing, allowing scientists to transfer multiple samples simultaneously.
Multichannel Electronic Pipette
Multichannel electronic pipettes combine the efficiency of multiple heads with the ergonomic advantages of automation. Using both techniques can significantly improve efficiency when filling microplates. In many cases, the time required to complete a task can be reduced to less than a minute.
Serological pipette
In tissue and cell culture applications, serological pipettes are usually made of glass or polystyrene. In laboratories where sterilization is a priority, scientists often use disposable pipettes made of durable plastic. Serological pipettes are also commonly used for liquid doses above 1 mL.
Manual stepper pipette
With a dispensing range of up to 5mL, the pipette is ideal for basic and repetitive tasks. They are powered by the positive displacement principle and can be used to dispense small samples in rapid succession without refilling the chamber. Relying on the principle of positive displacement, manual stepper pipettes are ideal for difficult to handle viscous and volatile liquids.
