Spectrophotometry Determination of Molybdenum with N‐Cyanoacylacetaldehyde Hydrazone

N-cyanoacylacetaldehyde hydrazone (CAAH), which is a laboratory synthetic reagent, is proposed as a new reagent for spectrophotometry determination of microamounts of molybdenum at λmax 790 nm. The reagent forms 1:1 blue coloured complex with molybdenum (VI) in phosphoric acid solution. The stable blue colour is obtained finally after changing from yellow to green. The colour development depends on temperature, time and concentration of phosphoric acid. This reagent is applied for the determination of molybdenum in steel alloys and the results are satisfactory.