Fulvic acid extraction requires XAD-8, a resin used in the isolation of organic solutes, dialysis tubing and several common laboratory chemicals. These include hydrochloric acid (HCl), sodium hydroxide, potassium hydroxide (KOH), potassium chloride (KCl) and hydrofluoric acid (HF).
Roots are removed from the soil, which is then sifted until it passes through a 2.0 mm sieve. Once sifted, hydrochloric acid is added to the soil sample to lower the pH and obtain the proper ratio between liquid HCl and the dry soil sample.
The soil is neutralized with sodium hydroxide to reach a pH of 7.0. The solution is then settled overnight, and the liquid is separated using decantation or centrifugation. From here, the process of adding a chemical, allowing the solution to stand for 12 to 16 hours, then centrifuging to separate solid from liquid is repeated several times.