Spectrophotometric determination of trace amounts of molybdenum in vegetal and tobacco tissues with a new chromogenic reagent, dimethoxyhydroxyphenylflurone.

A simple method for the direct determination of trace molybdenum in vegetal and tobacco tissues with selectivity and sensitivity is reported. The advantages are the high sensitivity, ease of operation, good reproducibility, and simplicity of apparatus. In the presence of Triton X-100 and sulfuric-phosphoric acid medium, a new chromogenic reagent, dimethoxydroxyphenylflurone, forms a red complex with molybdenum(VI). The molar absorptivity is obeyed in the range of 0-8 microg/25 mL for molybdenum(VI). Most metal ions and 35000-fold amounts of iron do not interfere with the determination of molybdenum. The proposed method has been successfully used for the determination of trace amounts of molybdenum in vegetal and tobacco tissues.