Hi Karuppiah, the easiest way is to dissolve a certain amount of fertilizer in water, filter the solution if necessary and then determine the sulphate content in the solution (http://www.merckmillipore.com/DE/de/product/Sulfate-Test,MDA_CHEM-110019). You can then calculate back to potassium sulphate and with the weight of the dissolved fertilizer you can calculate the mass percentages. But be aware that this is only an estimation. You didn't ask for an exact method (e.g. ion chromatography).

I agree with Markus Christ

I too agree with Markus Christ..

If there are any other sulfates like sodium sulfate present, this procedure may not be useful. It should contain only potassium sulfate. Otherwise you have to test for absence of other sulfates

Hello Gangadhar, I totally agree. The process says nothing about the structure of the sulfate. Of course, you must be aware of this.

I totally agree with Markus Christ

I agree with Markus Christ + determine the potassium concentration not only sulphate concentration and you can to determine sulphate concentration in the solution by EDTA-Na2 and determine the potassium concentration by phlamephotometer then you can to change the concentration to K2SO4% depending on the amout of dissolving organic fertilizer in a known volume of water.

Dear Dr, Karuppiah

I agree with Dr. Ghafoor Ahmed Mam Rasul and Dr. Markus .

Best regards

I agree with Markus Christ only for estimation of potassium sulphate

Do you want to determine K2SO4 concentration or K2SO4 equivalent. If it is organic fertiliser no-inorganic fertiliser incorporated in this case yor can only analize K content of the fertilizer by simply digesting it. If inorganic K fertilizer is incorporated in this case you have to determine both K and S in the fertilizer. This should be water soluble fractions.

I agree with Markus Chris

I think that organic fertilizers treated as soil and then decompose the sulfates as decomposed in the soil

Using XRD or XRF