Chapter 5 Flashcards
In solution, the effect of ions present but not part of the reaction of interest
Common ion effect
A sample preparation technique that attacks and destroys most of the matrix, leaving analytes behind; primarily for inorganics and metals
Digestion
Electrostatic attractions or repulsions between partially (+) or (-) regions of two polar molecules
Dipole-dipole interactions
In drug analysis, a simple one-step extraction method in which a solvent is added to a solid sample. Typically, the next step is GCMS analysis of the extract
Dry extraction
The material that exists in a SPE or chromatographic column
Eluant
The solvent or mobile phase used in SPE or chromatography
Eluent
The ratio of products to reactants raised to the power of the coefficients
Equilibrium constant
The gas above a solvent or sample into which analytes can volatize
Headspace
An equation used to describe buffers and other weak acids; relates pH to pKa and concentrations of acid and conjugate base
Henderson-Hasselbalch equation
The law that relates partial pressure of a substance above a solution to the concentration in the solution; KH * Pa = [A]
Henry’s law
“Water loving”; water soluble; usually lipophobic
Hydrophilic
“Water hating”; water insoluble; usually lipophilic
Hydrophobic
The water solubility of a drug alone, not in the ionized form
Intrinsic solubility (So)
Electrostatic attractions or repulsions between an ion and a partially (+) or (-) region of a polar molecule
Ion-dipole interactions
Electrostatic attractions and interactions between two ions
Ion-ion interactions
In a large molecule, a site where ionization can occur typically in an acid/base manner
Ionization center
The pH at which a molecule with multiple ionization centers is neutral
Isoelectric point (isoelectric pH)
Generic symbol for the equilibrium constant
K
When a chemical equilibrium exists, any disturbance of the system will result in the system compensating
Le Châtelier’s principle
A rule of thumb concerning polarity and solubility. A polar molecule will dissolve in a polar solvent but not in a non-polar one
Like dissolves like (LdL)
Literally, “fat loving”; molecules that are more soluble in fats and oils than in water
Lipophilic
“Fat hating”; insoluble in nonpolar solvents; are usually hydrophilic
Lipophobic
In solid phase extraction or chromatography, the phase that moves over the solid or stationary phase; may be polar, nonpolar, or inert
Mobile phase
Separation or chromatography using a polar stationary phase and a nonpolar mobile phase
Normal phase
The pH at which a drug with an ionizing center is most soluble
pHmax
The -log of the quantity of interest such as pH or pKa
pK value
Arises from the asymmetric electron distribution around a molecule; leads to partially positive and partially negative areas
Polarity
The comparative affinity of a compound to different phases such as two different solvents; the basis of partitioning, separations, and chromatography
Relative affinity
In TLC, the distance that a compound migrates relative to the starting point
Retention factor
Separation or chromatography using a nonpolar stationary phase and a polar mobile phase
Reversed phase
An extraction in which one of the phases involved in the selective partitioning is bound to a solid support
Solid phase extraction
Extraction into a solid phase coated on a microfiber. The pre-concentrated analytes are typically introduced directly in the injector of a GC
Solid phase microextraction
S, calculated using Ksp
Solubility
Use of a solvent to extract an analyte or analytes from a matrix
Solvent extraction
A measure of the ability of a solvent to elute a material in solid phase extractions or chromatography, based on relative polarity
Solvent strength
A solid immobile material to which an active material is bound; the stationary phase in solid phase extraction or chromatography; may be polar or nonpolar
Stationary phase
Chromatography in which the solid phase is coated on a support such as glass and solvent is drawn up by capillary action
Thin-layer chromatography (planar chromatography)
