A new analytical approach for humin determination in sediments and soils

In this work a new analytical approach is proposed for the recovery of humin present in soil and sediments. The procedure is based on microwave oven treatment for humin deashing. In this way both the treatment time and the concentration of the HCl/HF mixture are significantly reduced (minutes rather than hours, 10% rather than concentrated). By means of the proposed scheme organic matter present in sediment and soil samples can be subdivided into the different fractions (hydrophobic and hydrophilic compounds, fulvic and humic acids, humin) making up the balance of organic carbon. Results obtained for samples characterised by different organic carbon content showed a loss of carbon ranging between 20% and 30%, consistent with previous reports about humin deashing.