Fig. 3
From: An optical sensor for selenite determination in aqueous samples
a Absorbance value of I3− loaded films as a function of concentration of Se (IV) in aqueous solution. b Calibration curve for variamine blue-oxidized sensor, absorbance recorded at 550 nm. [1 μg mL−1 Se (IV), 1 mL 2% KI and 1 mL 2 M HCl, 3 mL variamine blue dye solution (8 × 10−5 M) and 2 mL 1 M sodium acetate with 30 min equilibration]