Instrumental Analysis in Pharmaceutical Chemistry

Energy of Photon

• The energy of a photon is given by E = hf, where E is the energy, h is Planck's constant, and f is the frequency.

Characteristics of Electromagnetic Radiation

• Wavelength refers to the linear distance between two successive maxima or minima of a wave.
• The frequency of electromagnetic radiation is given by the formula f = E / h, where E is the energy and h is Planck's constant.
• The number of waves per 1 cm is represented by the wavenumber.

Electromagnetic Radiation

• Electromagnetic radiation moves in the form of waves.

Photon Energy

• The constant that represents the energy of a photon is Planck's constant (h).

Relaxation Process

• In the relaxation process, M can lose the gained energy through two ways: heat dissipation or photon emission.

Energy Absorption in Molecules

• The variety of energy absorption in molecules is determined by the vibrational and rotational modes of molecules.

Electronic Spectra

• σ and π electrons can be elevated to excited antibonding states when energy is absorbed in molecules.
• The primary influence on the absorption of electromagnetic radiation in the near UV-Vis regions is the electronic transition.

Bonding in Organic Molecules

• σ and π bonds in organic molecules can be elevated to excited antibonding states when energy is absorbed.

Instrumental Analysis

• The primary advantage of instrumental analysis over classical techniques like volumetric and gravimetric analysis is its higher sensitivity and accuracy.

UV-Vis Spectrophotometry

• UV-Vis spectrophotometry utilizes the UV region of the electromagnetic spectrum.
• The fundamental principle behind spectrophotometric analysis is the absorption of electromagnetic radiation by molecules.

Absorption Spectrum

• Factors such as pH, solvents, and concentrations can potentially cause shifts in the absorption spectrum of a compound.
• The primary limitation of classical volumetric and gravimetric analysis techniques is their low sensitivity and accuracy.
• λmax is necessary to define when discussing electronic spectra, and it is used in quantitative measurement.

Spectrophotometric Analysis

• When matter is subjected to radiant energy, it undergoes electronic energy changes.

Shifts in Absorption Spectrum

• A bathochromic shift refers to a shift towards longer wavelengths in the absorption spectrum.
• The hyperchromic effect refers to an increase in absorbance in the absorption spectrum.
• pH affects the absorption spectrum of compounds containing acidic groups by causing shifts in the absorption maxima.
• The hypochromic effect signifies a decrease in absorbance in the absorption spectrum.
• A shoulder in an absorption spectrum indicates the presence of overlapping bands.

UV Region

• The UV region of the electromagnetic spectrum ranges from 10 nm to 400 nm in terms of wavelength.

Visible Region

• The visible region of the electromagnetic spectrum ranges from 400 nm to 800 nm in terms of wavelength, and is characterized by wavelengths that can be seen by the human eye.

Color of Substances

• The color of any substance appears as the complementary color of the absorbed wavelength to the human eye.

Selective Absorption

• The process in which a chemical species selectively gains certain frequencies of electromagnetic radiation is called selective absorption.

Explore the principles of Volumetric, Gravimetric, Electrochemistry, Spectroscopy, and Qualitative Separation techniques in Analytical Chemistry with Dr. Mahmoud Mohamed Abbas. Learn about the advantages and limitations of Volumetric and Gravimetric analysis methods.