Relationship between sodium hydroxide concentration, tem­perature and peat humic compound solution optical density
It has been shown that it is necessary to take into account the changes in molecular structure of humic compounds in the process of product preparation by sodium hydroxide extraction. Heating humic compounds' solutions to 96-98 °C leads first to the increase of the optical density, but after the maximum, the optical density decreases slowly. The decrease continues after stop of heating and during solution storage at the temperature 18-20 °C for the next 24-48 hours.