Use of a multichannel photometer (Multiskan MS) for determination of humic materials in soil after their dichromate oxidation.

Methodology for the determination of humus and humic materials content in soil after dichromate oxidation using a multichannel automatic photometer (Multiskan MS) has been developed. The study presented here demonstrates the benefits of using this methodology for the rapid, reliable and accurate determination of humus and humic materials content in various soils. The method is characterised by good data repeatability and low labour and reagent inputs. Photometric estimation is assessed in various respects, and determination procedures are presented. We have compared the data obtained by the titrimetric method and the photometric method with the photometer Multiskan MS. The methods are well correlated. The regression equations and determination coefficients relating to the data obtained by different methods have been calculated. The best statistics of a comparison between the titrimetric ( y) and photometric ( x) methods of humus determination were obtained with a series of standards prepared from the soil samples of known humus content: R(2)=0.99; y=1.05 x-0.37; BIAS=0.24% of humus; SED=0.27% of humus.