Steps

Fractions

Reagents

Durations

F₁

Exchangeable Fraction

8 ml 1MMgC1₂ (pH7)

1 hr.

F₂

Carbonate Fraction

8 ml 5MNaOAC1₂ (pH5)

5 hrs.

F₃

Fe-Mn Oxide Fraction

0.04M NH₂0H.HCI

6 hrs 96 + 20C

F₄

Organic matter Fraction

30% H₂0₂ (pH2)

5 hrs 85 + 20C + 30 mins

F₅

Residual

Aqua-regia HC10₄

Until white fumes appeared