Overview

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• Source: Microbioz India


• Date: 16 Aug,2025

Accuracy and precision are crucial in laboratories everywhere. When it comes to measuring and transferring liquids, the Mohr pipette is a crucial to precision. Even though modern laboratories may prefer using automatic pipettes for ease of use, the Mohr pipette is still an invaluable tool in teaching laboratories and in manual tests where exact precision is crucial.

What Is a Mohr Pipette?

Like all volumetric pipettes, Mohr pipettes are designed to measure specific volumes of liquid, and they are a type of graduated pipettes. Unlike a volumetric pipette, which is designed for delivering one fixed volume, the Mohr pipette allows for flexibility because it has graduated markings along its length. This means users can tailor the measurement to an incredible variety of volumes as required in different experiments.

They are slightly different from a serological pipettes in that the Mohr pipettes are usually made of borosilicate glass and are designed to deliver liquid between two graduation marks. Unlike serological pipettes which are designed to deliver the liquid to the last drop, mohr pipettes can deliver liquid between benchmark graduation marks.

How Does It Work?

In the case of a Mohr pipette, the principles of operation closely correlate with the handling techniques of measuring a liquid.

1. Filling the Pipette – Using a pipette bulb or pump, a liquid sample is drawn into the pipette until slightly above the desired graduation mark.
2. Adjusting the Meniscus – The liquid is allowed to flow until the bottom of the meniscus is at the desired mark for the measurement.
3. Delivering the Liquid – The liquid is released slowly until at the lower graduation mark that indicates the required measured volume.

Following these steps adequately guarantees a specified volume is dispensed, this is critical for any precise analytical or quantitative work.

Uses of Mohr Pipettes in the Lab

In almost every laboratory, especially within the fields of chemistry, biology and medicine, precision is paramount. Other notable applications include:

1. Titrations – The precise addition of reagents for concentration determination.
2. Dilutions – Synthesis of a solution with defined molarity.
3. Biological assays – In cellular, enzymatic or proteomic research, precise volumes are required for sample processing.
4. Teaching laboratories – Introduction to pipetting for students and establishing accuracy in liquid measurement.

Advantages of Mohr Pipettes

1. Ability to measure various volume of the same liquid with a single pipette.
2. Higher precision of measurement when compared to using graduated cylinders.
3. Clear marks make the measurements quick and easy to read.
4. They have the added benefit of being durable and reusable.

Factors to Consider

Mohr pipettes have some advantages in terms of precision and reliability, but the user requires a steady hand and must have some level of training. Both liquid delivery and meniscus reading introduce possibilities for small inaccuracies. Because of this, many students tend to start their training with Mohr pipettes before progressing to digital and automatic pipettors.

Concluding Remarks

In the context of the lab, the Mohr pipette is glass, but in reality, it is a representation of precise liquid measurement. It is critical to the success of the experiments that the measurements have the level of flexibility and accuracy, especially in liquid dispense which requires precision. Even today, the ability to use a Mohr pipette is a fundamental requirement for a laboratory technician, despite increasing automation in the laboratory.