Single Channel Pipettes

A single channel pipette is an instrument used in laboratories to move a precise amount of liquid from one container to another. “Single channel” distinguishes the pipette’s one singular channel from multichannel pipettes, which may have 6, 8, 12, 24, or even up to 96 and 384 channels. Multichannel pipettes fill columns and rows of well plates – or even entire plates simultaneously. Single channel pipettes aspirate into and dispense from a single tip.

There are manual and electronic single-channel pipettes. Manual pipettes are controlled with the thumb, and electronic pipettes are driven by a precise electronic motor.

The volume range of a single channel pipette often spans 1x–10x. For example, 0.2–2 µL, 2–20 µL, 20–200 µL etc. A pipette’s nominal volume – how people refer to it – is the largest volume it can dispense (e.g., a 2 uL, 20 uL, or 200 uL pipette for the sizes just listed.)

Volumes as low as 0.2 uL and as high as 20 mL can be aspirated and dispensed from different sizes of single channel pipettes.

Pipetting accuracy is highest at the high end of a pipette’s volume range. Because of this, it’s best to use the lowest-volume pipette that covers the volume you are pipetting. For example, a 0.2–2 µL pipette will have better accuracy specifications for pipetting 2 µL than a 2–20 µL model.

Choosing the right single channel pipette is important. Pipetting is a physical task. It is often repetitive. To reduce or eliminate injury, choose a comfortable, ergonomic pipette with low plunger forces and low tip ejection forces. Identify a reliable pipette that is built for durability, with proven sealing performance year after year from routine preventive maintenance. Using these criteria to choose a single channel pipette will help you maintain accuracy and be able to reproduce conditions – and results.

For the best accuracy, choose the lowest-volume single channel pipette that can accommodate the volume you are pipetting. For example, a 20 µL pipette is an excellent choice for pipetting 18 µL.

Finally, look for a pipette that has excellent accuracy specifications.

A good-quality single-channel pipette will feel good in the hand. If manual, it will have low plunger forces and a low force required to eject tips. A good-quality electronic single-channel pipette also feels good in the hand and adds electronic precision and repeatability.

Accuracy specifications are another measure of quality for single channel pipettes. Specifications measure a single channel pipette’s performance at given percentages of a pipette’s nominal volume. Accuracy and precision are best toward the higher end of a pipette’s volume range and become competitive between different pipette brands at the low end of the volume range. Look for the lowest variability at the lowest volume reported. Accuracy is measured by systemic error, and precision is measured by random error. The lowest error rates at the lowest volume are one sign of a quality single channel pipette.

Single channel pipettes can be used in a majority of applications that involve liquid handling. This is why a single channel pipette is one of the most common instruments in any laboratory. Researchers use single channel pipettes to raise cells, study proteins, run PCR or ELISA experiments, perform next-generation sequencing, CRISPR, drug discovery matrices and many more.

While some single channel pipettes are delivered with a tool to self-calibrate, all pipettes should receive regular expert attention from a qualified pipette service provider on a routine basis. A high-quality pipette service provider follows ISO-certified procedures, produces traceable pipette service history records, and uses manufacturer-recommended parts and lubricants in a highly controlled environment.

Single channel pipettes are available through your laboratory’s lab manager, your organization’s purchasing portal or online. A new single channel pipette should be delivered with a certificate of conformity documenting its performance prior to sale. To purchase a high-quality Rainin single channel pipette, visit mt.com/pipettes or shoprainin.com if you reside in the U.S.

These are the best practices for using a single channel pipette:

a. Choose a high-quality single channel pipette and high-quality pipette tips

b. Securely load a fresh pipette tip to ensure airtight accuracy

c. To avoid cross-contamination, use a fresh tip whenever you change liquids

d. Set the volume by dialing the micrometer above the desired volume. Then dial down to it

e. Hold the single channel pipette vertically or close to vertical while you are handling liquid

f. Aspirate and dispense at an even, moderate pace to avoid bubbling or splashing

g. Avoid over-aspirating by maintaining a fairly shallow (10 mm – 2mm) liquid insertion depth

h. Complete each dispense by touching off the pipette tip against the container wall. This makes use of liquid adhesion to pull the full dispense volume into the receiving vessel

The best way to troubleshoot issues with a single channel pipette is through a service visit either at your lab or by mail. Qualified service personnel can quickly and verifiably test performance, test for leaks, refresh lubricants and replace seals, and other parts as needed, using manufacturer-recommended components.

To test whether your single-channel pipette is performing accurately, you can use an analytical balance or Rainin SmartCheck to take gravimetric measurements. Based on liquid type and environmental factors like atmospheric pressure and temperature, you can identify whether a pipette is performing within specifications.