Determintion of Mo in fertilisers according to colorimetric method (using Ferrous Ammonium Sulphate, SnCl2, Potassium Thio-cyanate and Isoamyl alcohol, phase separation method) is a cumbersome process.

Further Determination of Mo by AAS doesn't give much accurate result....as Mo being an anion.

Therefore I used the similar colorimetric method used for determination of available phosphate from soil. The difference is that in case of phosphate standard P solutions were treated with Mo used as complexing reagent following the addition of SnCl2. In my method I have used standard Mo solutions with fix P solution (prior to testing of appropriate strength) followed by SnCl2. I got results quite comparable with colorimetric method of phase separation.

Please suggest if any problem in performing this methods.