A	Optical density
AER	Anion-exchange resins
Ant	Anthocyanin
BET	Brunauer–Emmett–Teller
ATR–FTIR	Attenuated total reflection–Fourier transform infrared spectroscopy
CER	Cation-exchange resins
Ce	Equilibrium concentration of anthocyanins in the solution, (mg dm−3)
Cs	Total concentration of anthocyanins in the solution, (mg dm−3)
CS0	Total initial concentrations of anthocyanins in the external solution, (mg dm−3)
CSt	Total concentrations of anthocyanins at time t of contact of the external solution with the resin, (mg g−1)
CIER	Total concentration of anthocyanins in an ion-exchange resin, (mg g−1)
DVB	Divinylbenzene
ECH	Epichlorohydrin
IER	Ion-exchange resin
HPLC	High-performance liquid chromatography
Ka	Dissociation constant
KF	Equilibrium constant of adsorption in Freundlich isotherm, (mg dm−3)−1
KL	Equilibrium constant of adsorption in Langmuir isotherm, (mg dm−3)−1
l	Optical path length of a cuvette, (1 cm)
m	Mass of the swollen resin, (g)
M	Molecular weight of cyanidin-3-glucoside, (449.2 g mol−1)
n	Adsorption intensity
PEPAs	Polyethylene polyamines
PS	Polystyrene
qm	Amount of adsorbate corresponding to complete monolayer adsorption, (mg g−1)
qe	Amount of adsorbate adsorbed on the solid surface at equilibrium concentration, (mg g−1)
VIER	Volume of the swollen resin, (cm3)
V1	Volume of the volumetric flask used to dilute the sample, (cm3)
Vs	Volume of solution in contact with the resin, (cm3)
ε	Molar extinction coefficient of cyanidin-3-glucoside, (26,900 [mol cm dm−3]−1)
ρ	Density of the swollen resin, (g cm−3)