34 Questions
What is the primary focus of the PHC 429 course?
Modern Instrumental Analytical Techniques
What is the prerequisite course for PHC 429?
Pharmaceutical Analytical Chemistry
Which of the following is NOT a type of titration?
Gravimetric titration
What is the title of the textbook by Galen Ewing?
Instrumental Methods of Chemical Analysis
What is the title of the second textbook mentioned?
Instrumental Analysis
Which of the following is NOT a type of spectroscopic method?
Conductometry
What is the primary classification of analytical techniques?
Qualitative and Quantitative
Which of the following is an electrochemical method?
Conductometry
What is the type of transition associated with the overall rotation of the molecule?
Rotational transition
What is the energy range of rotational transitions compared to electronic transitions?
1:10,000
What type of radiation is absorbed by a molecule undergoing a rotational transition?
Microwave radiation
What is the total energy of a molecule comprising of electronic, vibrational, and rotational energies?
E total = E electronic + E vibrational + E rotational
What is the type of transition associated with the motion of atoms within the molecule?
Vibrational transition
What type of radiation is absorbed by a molecule undergoing a vibrational transition?
Infrared radiation
What is the effect of conjugation on the maximum wavelength?
An increase in maximum wavelength (red shift)
What is the effect of pH on the absorption spectrum of aniline?
A hypsochromic shift with a hypochromic effect
What is the maximum wavelength of -C=C-C=C-?
326 nm
What is the energy required for a photon to give a specific transition in a molecule?
$E = h \nu$
What is the effect of protonation of the amino group on the absorption spectrum of aniline?
The spectrum becomes similar to that of benzene
What is the state of the molecule after absorbing energy from EMR?
Excited state
What is the relationship between the number of double bonds and the maximum wavelength?
An increase in the number of double bonds results in an increase in maximum wavelength
What is the duration of the excited state of a molecule before it relaxes to its ground state?
10-6-10-9 S
What is the difference between the energy of the excited state and the ground state of a molecule?
$E1 - Eo$
What is the maximum wavelength of aniline in acid medium?
254 nm
What type of spectroscopy is used to study the interaction of molecules with radiowaves?
Nuclear Magnetic Resonance (NMR)
What is the process by which a molecule returns to its ground state after being excited?
Relaxation
What does the proportionality constant 'K' represent in the equation Log Io / I = K C?
A constant value for a specific solute
What is the unit of concentration 'C' in the equation Log Io / I = a b C?
g/L
What is the relationship between absorbance 'A' and the concentration 'C' of the absorbing solute?
A is directly proportional to C
What is the term for the maximum absorptivity of a solute at a specific wavelength?
εmax
What is the difference between Beer's law and Lambert's law?
Beer's law relates to the path length of the light, while Lambert's law relates to the concentration of the solute
What is the significance of the symbol 'b' in the equation Log Io / I = a b C?
It represents the path length of the light
What is the unit of absorptivity 'a' in the equation Log Io / I = a b C?
L/g
What is the expression for absorbance 'A' when the concentration 'c' is expressed in g/100 mL?
A = a1c b c
Study Notes
Course Information
- Course ID: PHC 429
- Course Name: Pharmaceutical Instrumental Analysis I
- Number of Credits: 1+1
- Prerequisites: Pharmaceutical Analytical Chemistry
Instrumental Analysis Techniques
- Quantitative techniques:
- Volumetric analysis
- Gravimetric analysis
- Instrumental analysis
- Qualitative techniques:
- Organic analysis
- In-organic analysis
- Instrumental analysis
Spectroscopic Methods
- Ultraviolet and Visible Spectroscopy
- Fluorescence Spectroscopy
- Atomic absorption Spectroscopy
- Atomic emission Spectroscopy
- Nuclear Magnetic Resonance (NMR)
- Mass Spectrometry
- X-Ray Spectroscopy
Electrochemical Methods
- Potentiometry
- Conductometry
Optical Methods
- Polarimetry
- UV (Ultraviolet) - VIS spectrophotometry
- Visible light (Vis)
- IR (Infrared) - IR-spectroscopy
- Microwaves - Microwave spectroscopy
- Radiowaves - Nuclear Magnetic Resonance (NMR)
Molecular Response to Radiation
- Molecules can absorb light energy in three ways:
- Rotational transition
- Vibrational transition
- Electronic transition
- E total = E electronic + E vibrational + E rotational
- Relative energies: 10,000 : 100 : 1
Rotational Transition
- Associated with the overall rotation of the molecule
- Example: microwave irradiation
Vibrational Transition
- Associated with the motion of atoms within the molecule
- Example: IR radiation
- Factors affecting absorption of radiant energy:
- Affect of absorbing groups (or Chromophores) and conjugation
- Effect of pH on absorption spectra
Factors Affecting Absorption Spectrum
- (a) Affect of absorbing groups (or Chromophores) and conjugation:
- Conjugation occurs when two chromophores are separated by a single bond
- Example: -C=C- , -C=C-C=C- , -C=C-C=C-C=C- , -C=C-C=C-C=C-C=C-
- (b) Effect of pH on absorption spectra:
- Example: Aniline (NH2) in acid medium (HCl) shows hypsochromic shift with hypochromic effect
Laws of Light Absorption
- Beer's - Lambert's Law:
- Relates absorption capacity to the thickness of an absorbing solute (path length of light) and the concentration
- Log Io / I = a b C
- A = abC (absorbance)
- a = absorptivity, b = light path length (in cm), C = concentration (in g/L)
- Expressions of absorptivity (a) and Molar absorptivity (ε)
- A = εb c (if concentration is expressed in molar solution)
- ε at lmax is called εmax
This course provides an introduction to instrumental analysis in pharmaceutical sciences, covering techniques and applications. It builds on the foundation of pharmaceutical analytical chemistry and is a crucial part of the pharmaceutical industry. Students will learn about various instrumental methods and their uses.
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