Pharmaceutical Analysis (Pharm Chemistry-III) Vocabulary Flashcards

Comprehensive vocabulary flashcards covering major instrumental analysis terms, principles, and chromatographic concepts from the Pharm D Pharmaceutical Chemistry-III past papers.

Chromophore

A functional group or covalently unsaturated structure within a molecule that is responsible for absorbing ultraviolet or visible radiation.

Bathochromic Shift

A shift in the absorption maximum of a spectrum to a longer wavelength, commonly referred to as a red shift.

Guard Column

A short protective column placed upstream of the primary analytical column in HPLC to remove particulate matter and strongly retained contaminants.

Electronic Transition

The promotion of an electron from a ground-state molecular orbital to a higher-energy unoccupied orbital upon absorption of electromagnetic energy.

Stretching Vibration

A rhythmic molecular movement along the bond axis that results in a continuous change in the distance between two bonded atoms.

Spectral Interference

An analytical signal overlap or background contribution caused by species other than the intended target analyte during spectroscopic measurement.

Retention Time

The time elapsed between sample injection into a chromatographic system and the elution peak maximum of a specific compound.

Spectroscopy

The branch of science focused on measuring and analyzing the interactions between electromagnetic radiation and matter.

Chromatography

A separation method in which components of a mixture are partitioned between a stationary phase and a mobile phase.

Rf Value

The ratio of the distance traveled by a solute spot to the distance traveled by the solvent front in planar chromatography.

Isocratic Elution

A chromatographic operation where the solvent composition of the mobile phase remains constant throughout the entire separation process.

Gradient Elution

A chromatographic operation where the mobile phase composition is varied systematically during the analytical run.

Diffraction Grating

An optical device with a surface ruled with numerous closely spaced parallel lines used to disperse polychromatic light into its component wavelengths.

Beer-Lambert Law

A fundamental law stating that the absorbance of a solution is directly proportional to solute concentration and path length, expressed as $A = \frac{\text{absorbance}}{\text{path length} \times \text{concentration}}$.

Partition Chromatography

A separation process based on the relative solubility differences of solutes between a liquid stationary phase and a mobile phase.

Coupling Constant

A quantitative measure of spin-spin interaction between adjacent nuclei in $NMR$ spectroscopy, denoted as $J$ and measured in $Hz$.

Plate Theory

A theoretical chromatographic model that models the separation column as a series of discrete equilibrium stages termed theoretical plates.

Rate Theory

A chromatographic theory that accounts for band broadening using kinetic variables such as eddy diffusion, longitudinal diffusion, and mass transfer resistance.

Retention Volume

The total volume of mobile phase required to elute a specific solute from a column, equal to retention time multiplied by flow rate.

Electrode Potential

The potential difference developed across the interface between a conducting electrode and an electrolyte solution.

Spin Flipping

The transition of a nuclear magnetic spin state from a lower-energy orientation to a higher-energy orientation upon absorption of radiofrequency radiation.

Spin Relaxation

The thermodynamic process through which excited nuclear spins release energy and restore thermal equilibrium in $NMR$.

Bending Vibration

A molecular vibrational mode that causes a change in the interbond angle between three atoms without altering individual bond lengths.

Hypsochromic Shift

A spectral shift where absorption shifts toward a shorter wavelength, commonly termed a blue shift.

Auxochrome

A functional group containing non-bonding electrons that shifts the absorption position and enhances the intensity of a chromophore.

Capillary Electrophoresis

An instrumental separation technique using high electric fields to separate charged particles inside narrow capillaries based on electrophoretic mobility.

Adsorption Chromatography

A separation method dependent on solute molecules competing for physical adsorption sites on a solid stationary surface.

Fluorescence

The rapid re-emission of absorbed light energy occurring from a excited singlet state back to the ground state.

Argentometry

A precipitation titrimetric method in analytical chemistry that uses standardized silver nitrate as the titrating agent.

Potentiometry

An electroanalytical method that determines solute activity by measuring cell potential under zero-current flow conditions.

HPTLC

High-Performance Thin-Layer Chromatography; an enhanced version of TLC utilizing high-efficiency small-particle stationary phases for superior separation resolution.

Wave Number

The spatial frequency of electromagnetic radiation defined as the reciprocal of wavelength, typically expressed in units of $\text{cm}^{-1}$.

Redox Reaction

A chemical reaction involving the transfer of electrons where reduction and oxidation processes occur simultaneously.

Mobile Phase

The fluid medium carrying the sample mixture through a chromatographic column or stationary phase bed.

Transmittance

The proportion of incident light intensity passing through an absorbing sample medium, defined as $T = \frac{I}{I_0}$.

Phosphorescence

A delayed emission of light involving a spin-forbidden transition from an excited triplet state back to the ground singlet state.

Chemical Shift

The variation in resonant absorption frequency of a nucleus relative to a standard standard sample in $NMR$, measured in units of $\text{ppm}$.

Dropping Mercury Electrode

A polarographic working electrode that continuously forms renewable liquid mercury droplets at a capillary tip.

Differential Scanning Calorimetry

A thermal analysis technique measuring the difference in heat energy needed to maintain equal temperatures between a sample and reference standard.

Radioactivity

The spontaneous nuclear transformation of unstable atomic isotopes accompanied by the emission of energetic radiation.