Isolation and Characterization of Standard Fulvic Acids from Soil and Sediments in China

Fulvic acids(FAs) were isolated from soil(Jiufeng Forest,Beijing) and sediments(Zhushan lake district,Lake Taihu,Jiangsu) according to the method recommended by the International Humic Substances Society(IHSS).The FAs were characterized by elemental analyzer,UV-Vis spectroscopy,three-dimentional fluorescence spectroscopy,FT-IR spectroscopy,and 13C NMR spectroscopy,in order to compare the FAs with that of the IHSS.The results showed that the FAs derived from the soil(Soil FA) and sediment(Sediment FA) had similar elemental composition,ash contents and structure to the IHSS FA,and they had a certain comparability with the IHSS FA.This indicates that the Soil FA and Sediment FA were worthy to be popularly applied as potential standard FAs in China.Further analyses showed that there were some differences in composition and structure among the FAs,due to the various origins and environmental conditions by which FAs come into being.Both the IHSS FA and Sediment FA exhibited a higher content of aromatic carbons than Soil FA,possibly due to the degradation of microorganisms and aquatic plants abundant in the aquatic system.The FAs showed different polarity in the order of Soil FASediment FAIHSS FA.