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 μg 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.