Automatic Pipette

Quick Answer: An automatic pipette, in glassware terms, is a self-zeroing pipette that fills from a reservoir and sets its own volume by overflow, so the same measured quantity of liquid can be dispensed again and again without adjusting the meniscus by eye. It is used for repetitive dispensing of one reagent.

Repeat Dispensing Without Reading a Mark

Measuring the same volume many times with an ordinary pipette means drawing liquid above the mark and letting it down to the mark by eye, every time. The automatic pipette removes that step. In the usual glass design it is connected to a reservoir of reagent; liquid is raised until it overflows at the top of the measuring chamber, the excess runs off, and the chamber then holds exactly its set volume, which is delivered by turning a stopcock.

That makes the self-zeroing design useful where one reagent goes into many samples: dispensing acid in routine milk-fat tests, adding a fixed volume of buffer or indicator to a series of titration flasks, or preparing a set of identical reaction mixtures for a class rates practical. The reagent stays in its reservoir between measurements, which keeps it clean and limits exposure to fumes.

The same name is also used loosely for adjustable piston micropipettes, which are quite different instruments. Confirm which type is supplied, and its volume, before ordering.

Specifications

Applications

• Adding the same volume of acid or reagent to a long series of samples in routine testing
• Dispensing indicator or buffer into several titration flasks in turn
• Preparing identical reaction mixtures for a class rates-of-reaction practical
• Dairy and food testing laboratories where one reagent is dispensed many times a day

Care & Handling

• Keep the reservoir closed and labelled, and refill it only with the same reagent.
• Check the overflow outlet is clear before each session; a blocked overflow stops the pipette setting its volume.
• Flush the pipette and reservoir with distilled water when changing reagents.
• Stand the reservoir on a stable base and never lift the assembly by the pipette.

Why Choose LabEquip

Food, dairy and water testing laboratories and busy teaching labs use automatic pipettes where the same volume is measured dozens of times. LabEquip lists this pipette in its chemistry lab equipment range with the bulb type pipette for single accurate volumes; confirm the type and volume you need through the contact page.

Frequently Asked Questions

How does a self-zeroing pipette set its volume?

It is filled past its capacity so that liquid overflows at the top of the measuring chamber. The excess runs away through the overflow, leaving exactly the volume fixed by the chamber, which is then delivered through the stopcock.

Is an automatic pipette the same as a micropipette?

Not necessarily. In glassware catalogues the name means a self-zeroing glass pipette on a reservoir, while a micropipette is an adjustable, piston-operated instrument with disposable tips for microlitre volumes. Confirm which one you need when you enquire.

Is it more accurate than a bulb pipette?

Its main advantage is speed and consistency when repeating one volume. A bulb pipette used with careful technique is usually the reference for a single accurate volume, so many laboratories keep both.

Which reagents can be dispensed?

Aqueous reagents, acids and alkalis are typical. Volatile or foaming liquids can upset the overflow setting, and reagents that attack stopcock grease need a greaseless stopcock.

Does it remove the need for a pipette filler?

Yes. In the reservoir design the liquid is raised mechanically rather than by suction, so there is no mouth or bulb pipetting. That is one reason this design is used for strong acids in routine tests.

How is the delivered volume checked?

Dispense several portions of distilled water into a weighed container and weigh each one. At room temperature one gram of water is close to one cubic centimetre, so the mass shows whether the volume is correct.

Last Updated: September 2026