volumetric pipette

November 2, 2021

Laboratory instruments are diverse elements, each one with a specific function within it. A volumetric pipette is a clear example of this, it is a tool used to measure and transfer small amounts of liquids.

What is it?

It is a laboratory instrument used to measure and transfer small amounts of liquid. It is a glass tube open at both ends and wider in its central part. The lower end ends in a point and the liquid is introduced through it by sucking through the upper end.

There are two types of pipet, the Mohr or graduated pipet and the pouring pipet. The first allows to measure different volumes of liquid because it has a graduated scale. The pouring pipette has a circular mark on the top and only measures one volume.

They have a capacity of between 1 and 100 ml.

Characteristics

The volumetric or volumetric pipette is used for the measurement of liquids in the laboratory and their pouring. It is made of borosilicate, a material that is easy to clean, inert and with little deformation.

Class A pipettes are the most accurate , they are used in analytical chemistry to develop standardized solutions.

Class B pipettes have twice the error than those of class A , they are used for non-standardized solutions for daily use in a laboratory.

Pipettes have a bulge on the barrel and a taper at the bottom. This type of pipettes are calibrated for a specific volume, that is, they only transfer the volume indicated and calibrated by the capacity.

How is it used?

Pipettes feature gauges or measurements that establish the amount of liquid and are recommended for use when accuracy and reproducibility are required. They may have one or two gauges.

When there is only one capacity or mark on the ampoule, we must ring up to that mark so that when emptying it, it dumps the amount of volume indicated on the outside. You need to wait up to 15 seconds for the last drop to fall.

If it presents two gauges or marks, that is, one above the blister and another below, it means that we must ring it up to the upper mark but when emptying it, you must do it up to the lower mark and no more than that, that way you will pour the volume indicated on the outside.

Usage precautions

  • It must always remain clean.
  • Before using it, it must be washed and purged three times with the liquid to be transferred to ensure that any drops of liquid that may remain adhered will correspond to the liquid to be measured.
  • The mouth should not be used, it is filled by means of a propipette and never by our own suction.
  • They should not be used for blown emptying, under no circumstances should the remaining liquid that may remain in the pipette when emptying be blown.

Uses of the volumetric pipette

  • It is used in analytical chemistry.
  • It is used in the preparation of solutions that require rigorously known concentrations.
  • They are used to determine the acidity of solutions.
Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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