Definitions Flashcards
Base peak
Peak of greatest abundance in a mass spectrum
Molecular ion peak
A peak produced by an ion formed by the removal of one electron from a molecule
M+1 peak
A peak produced by a molecular ion with an increased mass due to the presence of one carbon-13 atom
Fragmentation ion
A positively charged ion produced when the molecular ion breaks apart
Low resolution nmr
A spectrum which does not show the spin-spin splitting pattern
High resolution nmr
A spectrum which does show the spin-spin splitting pattern
Doublet
A signal which appears as a pair of lines of equal intensity
Triplet
A signal which appears as three lines in the approximate intensity ratio (1:2:1)
Quartet
A signal which appears as four lines in the approximate intensity ratio (1:3:3:1)
Back titration
Method where an excess of reagent is reacted with a sample. The unreacted reagent is then determined by titration
Rf values
Retardation factor, this is calculated using the expression
Rf= Distances moved by spot/ Distance moved by solvent
Retention time
The time taken from injection until a component reaches the detector
Transition metal
An element which forms at least one stable ion with a partially filled d-subshell
Complex
A central metal atom or ion with ligands bonded by co-ordinate bonds
Ligand
An ion or molecule with a lone pair of electrons which forms a co-ordinate bond with a central metal atom or ion in a complex
Co-ordination number
The number of co-ordinate bonds to a central metal atom or ion in a complex
Monodentate
A ligand which uses only one lone pair of electrons to form a co-ordinate bond with a central metal atom or ion in a complex
Bidentate
A ligand which uses two lone pairs of electrons to form two co-ordinate bonds with a central metal atom or ion in a complex
Polydentate
A ligand which uses many lone pairs of electrons to form more than two co-ordinate bonds with a central metal atom or ion in a complex
Standard electrode potential
The potential difference measured when a half-cell is connected to the standard hydrogen electrode under standard conditions
e.m.f
The potential difference measured when two half-cells are connected
Primary amine
Only one carbon atom directly bonded to the nitrogen atom and therefore has the (-NH2) group
Secondary amine
Two carbon atoms directly bonded to the nitrogen atom, ie |
—NH
Tertiary amine
Three carbon atoms directly bonded to the nitrogen atom ie. |
—N
|
Coupling
A reaction in which two benzene rings are linked together through an azo (-N=N-) group
Dehydration of amides
A reaction which involves the elimination of water from the amide
Zwitterions
Ions which have a permanent positive and negative charge but which are neutral overall
Primary structure (proteins)
Sequence of amino acids joined by peptide links in the chain
Secondary structure (protein)
The twisting/coiling of the chain to form a Beta-pleated sheet/ alpha-helix by intramolecular hydrogen bonding
Tertiary structure (protein)
The bending/folding of secondary structure to give a precise 3D shape held together by hydrogen bonding/disulfide bridges/ionic interactions/van der Walls’ forces
Enzyme
A protein which is a biological catalyst
Active site
The site on the surface of the enzyme into which the substrate fits
Induced fit
The substrate induces a change of shape of the active site of the enzyme
Condensation polymers
Polymers formed by the elimination of small molecules such as water or hydrogen chloride when monomers bond together
Biodegradable polymer
A polymers which can be hydrolysed by the action of microorganisms
DNA replication
The process by which a double stranded DNA molecule is copied to produce two identical DNA molecules
GLC-MS
A gas liquid chromatograph attached to a mass spectrometer
Sequestering
The formation of a complex so that an ion is no longer available for reactions
