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Spectrophotometry Test

By @forensicfield

What is Spectrophotometry Test?

Spectrophotometry is measuring intensity of light in a part of the spectrum as transmitted by particular substances.

Spectrophotometry Test is based on the identification of hemoglobin and its derivatives (such as; methamoglobin, carboxyhemoglobin, oxyhemoglobin.) through their specific absorption spectra.

It’s Uses In Forensics

It’s a Confirmatory test for blood.

This method was considered one of the most conclusive test for the identification of blood stains.

Basis Of The Test

Hemoglobin and its derivatives exhibit characteristic bands of absorption at specific wavelength , which can be observed by spectrophotometer.

Indication for the Presence of Blood

It produced specific absorption spectra for hemoglobin and its derivative for identification of blood.

How To Perform This Test ?

A complex system of band is present because of heme (part of hemoglobin) in the near UV and Visible region of spectrum.

Sometimes they differs from derivative to derivative of heme portion but they all have common strong absorption band  at 400-425 nm which is also known as Soret Band.

Drawbacks

  • It can not differentiate between Sample and things which produce same wavelength.
  • Low Sensitivity.

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