Dissolving tubeDegradation methods in soil

Instrument: PTFE digestion tube

Reagent:

1. Hydrochloric acid (HCl): ρ=1.19g/mL, of superior purity

2. Nitric acid (HNO3): ρ=1.42g/mL, of superior purity

3. Hydrofluoric acid (HF): ρ=1.49g/mL

4. Perchloric acid (HClO4): ρ=1.68g/mL, of superior purity

Steps:

1. Weigh 0.2-0.5g of soil sample into a polytetrafluoroethylene digestion tube, add 10mL of hydrochloric acid HCl, and insert it into the digestion well.

2. Set the temperature of the digestion instrument to 140 ℃ and the time to 60 minutes. Heat until a small amount of sample remains, then remove and cool.

3. Add 5mL of nitric acid HNO3, 5mL of hydrofluoric acid HF, and 3mL of perchloric acid HClO4, shake well.

4. Set the temperature of the digestion instrument to 160 ℃, heat up for about 1 hour, and cool down.

5. Continue heating and evaporating the silicon, raise the temperature to 160 ℃, wait for a small amount of concentrated white smoke to evaporate, and wait for 60 minutes. Remove and cool. After reaching a certain volume, the liquid becomes transparent.