Description and working steps
Particle fractionation: 30 g of bulk soil samples (<2 mm) were dispersed ultrasonically at 22 J/mL, sieved with 20 μm mesh size and air dried.
H2O2 oxidation: 30 g of <20 μm soil was suspend into 500 mL of 15% H2O2 at room temperature and allowed the suspension to react until the gas development ceased. Then the samples were treated with 30% H2O2 at 70°C until the visible reaction ceased (average 1-3 days). The treated suspensions then dried at 40°C and collected for further analysis.
The original aim of this scheme was to check the effectiveness of H2O2 on removal of organic carbon and total nitrogen for mineral soil fractions (< 20 μm) of agricultural soils.
- Relatively easy and not too delicate method.
- H2O2 treatment can be less effective for sample with higher organic matter content.
- Time consuming method (about 6 days for a batch of samples); however, 50% of the time, the samples were kept unattended (while overnight treatment with 15% H2O2 + continuous treatment with 30% H2O2 for 3 days).
Leifeld, J., Kogel-Knabner, I., 2001. Organic carbon and nitrogen in fine soil fractions after treatment with hydrogen peroxide. Soil Biology & Biochemistry 33, 2155-2158.