Аннотация:Until now, there were no humic acids (HA) standard samples of a high level of
accreditation in the world. The most popular and famous are standard samples of
International Humic Substances Society, IHSS (http://humic-substances.org/ihss-samplesa-
retrospective).
The goal of our work was producing standard samples of chernozem and sodpodzolic
soil HA, which can be further used for evaluating other samples of humic
materials. Standardization of HA samples was performed in terms of carbon, nitrogen and
hydrogen contents as determined by elemental analysis. Produced HA standard samples
correspond to the state standard level.
Soil sampling: chernozem soil was collected in the field of long-term experiment
(grain-and-fallow crop rotation since 1964) in Kursk region. Sod-podzolic soil was collected
in Moscow region in spruce forest of more than 150 years old. About 50 kg of each soil
was collected and used for HA isolation using IHSS protocol [1].
Samples of HA were attested in Russian Federal Agency on Technical Regulating
and Metrology using standardized method of elemental analysis. Content of elements in
chernozem soil HA was determined as: C 54.60±0.91%, H 3.16±0.38% and
N 3.22±0.40%. For sod-podzolic soil HA elemental composition was determined as:
C 48.9 ± 0.7%, H 5.05±0.25% and N 5.08 ± 0.26%. In addition standard samples of HA
were characterized by molecular mass distribution using HPLS and structural fragment
carbon distribution using liquid-state 13C-NMR and UV-vis spectrometry.
So, standard samples of soil HA were produced for the first time.
References
1. Swift R.S. // Methods of soil analysis. 1996. 3:1018-1020.
This research was supported by the Russian Science Foundation grant 14-26-00079.