Page 18 - Instrumental Analysis - Pharm D Clinical- 07-PA403

UV-visible Spectrophotometry

Factors affecting shape of the
absorption spectrum

• Change in chromophore of the compound due to degradation or any
chemical reaction.

• pH of the solution especially for compounds carrying acidic or basic
functional groups.

• Solvent where solution is prepared.

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Changes and shifts that may occur in the
absorption spectra

• Bathochromic shift (red shift): shift of the absorption maximum to longer λ.
• Hypsochromic shift (blue shift): shift of the absorption maximum to shorter λ.
• Hyperchromic effect: increase in the absorption intensity.
• Hypochromic effect: decrease in the absorption intensity.

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