# Beer-Lambert Law question

• sicjeff
In summary, the molar absorption coefficient for acetonitrile is not available in the visible spectrum. However, it can be found in the deep UV spectrum (down to 200 nm) in the Fisher catalog for the Optima grade. The absorbance at 200 nm is equal to or less than 0.07. Acetonitrile is also completely miscible in water. Suggestions for a liquid immiscible in water that absorbs in the visible spectrum were requested, and the solute and purpose of the investigation were asked for. It is noted that acetonitrile is potentially UV active.

#### sicjeff

Does anyone know the molar absorption coefficient for acetonitrile? I need to know what wavelength the coefficient is at of course as well. Hopefully I can find one in the visible spectrum. My department does not have an ultra violet spectrophotometer.

I guess I should pick easier thermodynamic experiments

Acentonitrile does not have an appreciable visible absorbance.

Look in a Fisher catalog for the Optima grade. You will see that it has no appreciable absorbance down to 200 nm (deep in the UV!).

Absorbance (200nm) <= 0.07

thank you. I guess I will have to pick something else. Could anyone suggest a liquid immiscible in water that absorbs in the vis spectrum?

What is the solute and what, in general terms, are you trying to investigate?

BTW, acetonitrile is completely miscible in water. Good thing it didn't work out, yes?

i would suspect that acetonitrile is uv active

## 1. What is the Beer-Lambert Law?

The Beer-Lambert Law, also known as the Beer-Lambert-Bouguer Law, is a mathematical relationship that describes the attenuation of light by a sample of a substance. It states that the amount of light absorbed by a sample is directly proportional to the concentration of the substance and the path length that the light travels through the sample.

## 2. What is the significance of the Beer-Lambert Law in science?

The Beer-Lambert Law is an important tool in the field of spectroscopy, which is used to study the interaction of light with matter. It is commonly used to determine the concentration of a substance in a solution, as well as to identify unknown substances through their absorbance spectra.

## 3. What are the limitations of the Beer-Lambert Law?

The Beer-Lambert Law assumes that the sample is homogeneous, meaning that the concentration of the absorbing substance is constant throughout the sample. It also assumes that the light source is monochromatic and that the path length is uniform. Additionally, the law is only valid for dilute solutions and may not accurately describe the behavior of highly concentrated solutions.

## 4. How is the Beer-Lambert Law used in practical applications?

The Beer-Lambert Law is commonly used in industries such as pharmaceuticals, environmental monitoring, and food and beverage production. It is used to measure the concentration of drugs in patient samples, pollutants in the environment, and the quality and consistency of products in the food and beverage industry.

## 5. Can the Beer-Lambert Law be applied to other forms of radiation besides light?

Yes, the Beer-Lambert Law can be applied to other forms of electromagnetic radiation, such as infrared and ultraviolet light. It can also be used to describe the attenuation of other types of radiation, such as acoustic or radio waves, by a sample. However, the specific parameters and equations may differ depending on the type of radiation being studied.