Optical Rotation Test

What Is Optical Rotation?

Optical rotation is a term that describes a substance's ability to twist polarized light. When polarized light passes through a substance (liquid) or a solution of substances (solid substance), it causes a rotation in the plane of polarization. This angle of rotation is referred to as the optical rotation.

Why Measure the Optical Rotation of Drugs?

The optical rotation test holds significant importance in drug research and development. Chiral centers within drug molecules can influence the optical rotation characteristics of drugs.Chiral drugs typically consist of two mirror-image isomers (enantiomers) that may exhibit distinct efficacy and toxicity within organisms.

Consequently, measuring a drug's optical rotation can assist researchers in determining the enantiomeric ratio within a drug molecule, providing insight into the drug's pharmacological properties.

Services at Protheragen-ING

Sample Preparation

Optical Rotation Test has certain requirements on the purity of the sample. Generally, the purity of the sample should be as high as possible. The solution of the sample is homogeneous and should remain stable during the test.

If the sample contains impurities, it may affect the optical rotation measurement results. Therefore, appropriate preparation and handling of the sample is usually required before optical rotation testing can be performed.

Optical Rotation Test

Testing and Analysis

The instrument used for measuring optical rotation is a polarimeter, which is an optical instrument used to measure the rotation of polarized light caused by optical activity in a sample solution.

Since various conditions such as sample tube, solution concentration, and temperature may vary during measurements, the optical rotation values measured under these differing circumstances can also differ.

To facilitate comparisons, the optical rotation measured under various conditions is usually converted into a specific rotation value per unit length of the sample tube and unit concentration. This value is referred to as specific rotation and is expressed in degrees per (decimeter·gram per milliliter) or degrees/(dm·g/ml).

The specific rotation is an inherent property of matter and remains constant regardless of changes in measurement conditions. So we need to convert the measurement value into a specific rotation value.


The results, including the specific rotation value and any relevant details such as temperature, solvent concentration or anything about the sample and measurement conditions, are documented in a report. This information is crucial for research and quality control purposes, especially in the pharmaceutical and chemical industries.

Client Consultation and Support

After submitting the report, we still remain accessible to address any questions or concerns our clients may have. Our team is committed to providing expert guidance as needed to ensure a complete understanding of the results.

If you are interested in our Optical Rotation Test and need more information please don't hesitate to contact us and we will respond promptly within 2-4 working days.


Daily: 9.30 AM–6.00 PM
Sunday : 9.30 AM–1.00 PM
Holidays: Closed

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