Molar Ellipticity Calculator

Formula

To calculate the Molar Ellipticity ( $[θ]$ ):

$[θ] = \frac{θ_{obs} \times MW}{10 \times l \times c}$

Where:

$[θ]$ is the Molar Ellipticity
$θ_{obs}$ is the Observed Ellipticity
$MW$ is the Molecular Weight
$l$ is the Path Length (cm)
$c$ is the Concentration (M)

What is Molar Ellipticity?

Molar ellipticity is a measure of the degree to which a substance can rotate plane-polarized light. It is commonly used in the field of circular dichroism spectroscopy to study the chiral properties of molecules, particularly proteins and nucleic acids. The molar ellipticity is calculated from the observed ellipticity, molecular weight, path length, and concentration of the sample. It provides insights into the secondary structure and conformational changes of biomolecules.

Example Calculation 1

Let's assume the following values:

Observed Ellipticity ( $θ_{obs}$ ) = 10
Molecular Weight ( $MW$ ) = 50000
Path Length ( $l$ ) = 1 cm
Concentration ( $c$ ) = 0.01 M

Using the formula:

$[θ] = \frac{10 \times 50000}{10 \times 1 \times 0.01} = 5000000$

The Molar Ellipticity is 5000000.

Example Calculation 2

Let's assume the following values:

Observed Ellipticity ( $θ_{obs}$ ) = 20
Molecular Weight ( $MW$ ) = 60000
Path Length ( $l$ ) = 2 cm
Concentration ( $c$ ) = 0.02 M

Using the formula:

$[θ] = \frac{20 \times 60000}{10 \times 2 \times 0.02} = 3000000$

The Molar Ellipticity is 3000000.