Spectrophotometric determination of manganese (II) with Mordant Brown 33 in the presence of Tween 20 in some foods

A facile, highly selective and sensitive spectrophotometric method has been developed for the determination of manganese (II) in different foods. The method is based on the formation of the binary complexes of manganese with Mordant brown 33 (MB33) 2, 4-diamino-5-(2-hydroxy-5-nitrophenylazo) benzene sulfonic acid sodium salt at pH 9.0 with Tween 20 at wavelengths 575 nm with molar absorbtivity 0.75 × 10⁴ l mol^-1 cm ^-1. Manganese was thus determined in the ranges 1.1-4.4 μg mL ^-1 in the presence of Tween 20. The detection limits were found to be 0.046 fig mL^-1. The effect of foreign ions was elucidated.The relative standard deviations were in all instances less than 1.2 %. The proposed method was successfully applied for the determination of manganese in different kinds of foods.