The Fertilisers (Sampling and Analysis) Regulations 1996 No. 1342

SCHEDULE 2 METHODS OF ANALYSIS

PART II

5. DETERMINATION OF POTASSIUM — GRAVIMETRIC METHOD

<1 Formaldehyde, 25 – 35% solution, filtered if necessary before use.

3.4  Indicator solution: dissolve 0.5 g phenolphthalein in 100 ml 90% ethanol.