In UV-Vis spectroscopy, what does a peak at 280 nm typically indicate?

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Question: In UV-Vis spectroscopy, what does a peak at 280 nm typically indicate?

Options:

Correct Answer: Presence of proteins

Solution:

A peak at 280 nm typically indicates the presence of proteins, particularly due to the absorbance of aromatic amino acids.

In UV-Vis spectroscopy, what does a peak at 280 nm typically indicate?

In UV-Vis spectroscopy, what does a peak at 280 nm typically indicate?

Step 1: Understand what UV-Vis spectroscopy is. It is a technique used to measure how much light is absorbed by a sample at different wavelengths.
Step 2: Know that different substances absorb light at specific wavelengths. This can help identify what is in the sample.
Step 3: Recognize that proteins are made up of building blocks called amino acids.
Step 4: Learn that some amino acids, like tryptophan and tyrosine, have special structures called aromatic rings.
Step 5: Understand that these aromatic amino acids absorb light strongly at a wavelength of 280 nm.
Step 6: Conclude that if you see a peak at 280 nm in a UV-Vis spectrum, it usually means that proteins are present in the sample.

UV-Vis Spectroscopy – A technique used to measure the absorbance of UV or visible light by a sample, which can indicate the presence of certain compounds.
Aromatic Amino Acids – Amino acids such as tryptophan, tyrosine, and phenylalanine that absorb UV light, particularly around 280 nm.
Protein Detection – The identification of proteins in a sample based on their characteristic absorbance at specific wavelengths.