Composition and structure of fulvic acids from B-horizon of ferro-humic podzol in Trojmezi (Bohemian Forest Mts.) in the Czech Republic
1999
Novak, F. | Kalouskova, N. (Akademie Ved, Ceske Budejovice (Czech Republic). Ustav Pudni Biologie) | Machovic, V. | Brus, J.
Fulvic acids (FA) isolated from podzol Bh horizon in Trojmezi stand (Bohemian Forest, Czech Republic, 48°46'25'' N, 13°51'04'' E) contain 44.82 % C,, 7.50 % H, 2.82 percent N, and 38.17 % O, C/N ratio is 15.9. The elemntal composition and C/N ratio agree with the "average" composition of FA1 according to Orlov. The absorbance intensity of FA in UV region corresponds probably to ET bands of carboxyphenols. The optical density of FA was low - 3.8. The carboxyl groups content in FA (including the carbonyl-C contribution) derived from the NMR spectrum was 8.0 mol.kg/l. An estimate of the average molecular weight (MW) of FA determined by low pressure gel permeation chromatography was - 1,800. About 15 % of FA have MW higher than 6.5.10E(3), and 33 % of FA lower than 1,000.
显示更多 [+] 显示较少 [-]