Abstract: A new spectrophotometric method for determining manganese in wine was established by calcein oxide. In sulfuric acid medium, calcein can be oxidized by manganese (VII) oxide to fade. A linear relationship between fading and the concentration of potassium permanganate was observed. The decreased absorbance proportional to the concentration of Mn (Ⅶ) oxidized by sodium bismuth could be determined by spectrophotometry. The maximum absorption was at 480 nm and the apparent molar absorption coefficient was 1.74×104 L/(mol·cm). The absorbance obeyed the Beer,s law in Mn (Ⅶ) concentration range of 0 to 2.7 μg/mL and the detection limit was 0.014 μg/mL. This developed method can result in results consistent with those from atomic absorption spectrophotometry. The spike recovery rates in beer, liquor and wine were between 97.0% and 102.7%.

Key words: manganese, spectrophotometry, calcein, wine