Particles+Oxidation Leifeld

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.

Initial Aim

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.

Advantages

• Relatively easy and not too delicate method.

Disadvantages

• 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).

References

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.