Repeater Pipettes

By clamping onto the plastic piston inside a disposable syringe tip, repeater pipettes precisely control the up and down movements of liquid in the tip. The piston-end is in direct contact with the sample at all times during the pipetting cycle of aspiration and dispensing. During aspiration, the piston is moved upward and the sample is drawn into the syringe tip. The repeater then pushes the piston down in equal steps known as aliquots, repetitively dispensing the same volume multiple times.

A repeater or repeating pipette can be used in almost any protocol. Use a repeater to prepare replicates, aliquot samples to smaller volumes for long-term storage, set up assays by dispensing volumes of a series of reagents, and even wash plates. Because they utilize positive-displacement syringe-style tips, repeater pipettes excel at handling challenging liquids (e.g. viscous, volatile, and dense).

Repeater pipettes include a built-in piston that extends flush to the end of each disposable positive-displacement syringe tip. Repeater pipettes – also referred to as multi-dispenser pipettes – are an excellent choice for working with challenging samples, such as viscous or volatile liquids.

Repeater pipettes use special tips for positive-displacement devices called “syringe tips". They are also sometimes referred to as "capillaries". Syringe tips contain an inner plastic piston that extends the full length of the tip. At volume -0-, the end of the inner piston blocks the open end of the tip.

As a user aspirates liquid, the end of the piston rises and pulls liquid into the tip. Unlike the more common air-displacement pipette, there is no air between the piston and the liquid, which is why positive-displacement pipetting is known for extreme accuracy.

While positive-displacement pipettes provide higher accuracy when pipetting any liquid, it’s important to note that positive displacement syringe tips – with plastic pistons built into each tip – come with a higher price point than regular pipette tips that fit air-displacement pipettes.

A repeater pipette can be used in any application or workflow that requires assay replication, or in cases in which accuracy and precision within samples is critical. For example, many pipette users prefer repeater pipettes for setting up PCR reactions. Repeaters can dispense the same volume of the PCR reaction mix into each PCR tube.

Another common application is aliquoting critical reagents or samples into vessels for long-term storage, such as serum from a patient that needs to be frozen. If such a sample is simply frozen in one large volume, unnecessary thawing cycles may compromise the integrity of the sample/biomarkers that are temperature sensitive.

Lastly, samples with high viscosity or volatility are usually difficult to pipette with air-displacement pipettes. This is because the forces these liquids exert on the air pocket between the piston and the liquid in air-displacement pipettes results in poor sample-to-sample replication (poor accuracy and precision). Repeater pipettes greatly improve accuracy and precision in applications or protocols dealing with challenging liquids.