THE RELATIVE IMPORTANCE OF MOLECULAR SIZE AND CHARGE DIFFERENCES IN CAPILLARY ELECTROPHORESIS OF HUMIC SUBSTANCES OF DIFFERENT ORIGIN

1998 ◽  
pp. 109-112
Author(s):  
Maria De Nobili ◽  
G. Bragato ◽  
A. Mori
Keyword(s):  
Capillary Electrophoresis ◽  
Humic Substances ◽  
Molecular Size ◽  
Relative Importance ◽  
Different Origin

scholarly journals Chemical Structure and Biological Activity of Humic Substances Define Their Role as Plant Growth Promoters

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2256
Author(s):  
Serenella Nardi ◽  
Michela Schiavon ◽  
Ornella Francioso
Keyword(s):  
Biological Activity ◽  
Humic Substances ◽  
Chemical Structure ◽  
Molecular Size ◽  
Growth Promoters ◽  
Root Cells ◽  
Sustainable Technologies ◽  
Intracellular Signals ◽  
Key Functional Groups ◽  
Regulatory Functions

Humic substances (HS) are dominant components of soil organic matter and are recognized as natural, effective growth promoters to be used in sustainable agriculture. In recent years, many efforts have been made to get insights on the relationship between HS chemical structure and their biological activity in plants using combinatory approaches. Relevant results highlight the existence of key functional groups in HS that might trigger positive local and systemic physiological responses via a complex network of hormone-like signaling pathways. The biological activity of HS finely relies on their dosage, origin, molecular size, degree of hydrophobicity and aromaticity, and spatial distribution of hydrophilic and hydrophobic domains. The molecular size of HS also impacts their mode of action in plants, as low molecular size HS can enter the root cells and directly elicit intracellular signals, while high molecular size HS bind to external cell receptors to induce molecular responses. Main targets of HS in plants are nutrient transporters, plasma membrane H+-ATPases, hormone routes, genes/enzymes involved in nitrogen assimilation, cell division, and development. This review aims to give a detailed survey of the mechanisms associated to the growth regulatory functions of HS in view of their use in sustainable technologies.

Capillary electrophoresis of humic substances in physical gels

2007 ◽  
pp. 109-120
Author(s):  
M. De Nobili ◽  
G. Bragato ◽  
A. Mori
Keyword(s):  
Capillary Electrophoresis ◽  
Humic Substances

scholarly journals Influence of the apparent molecular size of humic substances on the efficiency of coagulation using Fenton's reagent

2013 ◽  
Vol 85 (2) ◽  
pp. 833-848 ◽  
Author(s):  
MARCELO DE JULIO ◽  
TATIANE S. DE JULIO ◽  
LUIZ DI BERNARDO
Keyword(s):  
Humic Substances ◽  
Water Samples ◽  
Iron Concentration ◽  
Molecular Size ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Dissolved Air Flotation ◽  
Coagulant Dosage ◽  
Molecular Sizes ◽  
Apparent Colour

This work used Fenton's reagent as a coagulating agent in the treatment of water samples with high true colour caused by humic substances (HS) extracted from peat. In addition, the effects of the apparent molecular size of HS on coagulation, flocculation and flotation were studied. To that end, four distinct water samples having the same true colour were prepared using HS with different molecular sizes, which were obtained by ultrafiltration fractioning. Through optimisation of coagulant dosage and coagulation pH, as well as posterior construction of coagulation diagrams for each water sample, it was verified that the sample prepared with the smallest apparent molecular size of HS was the most difficult to treat, requiring higher coagulant (Fenton's reagent) dosages than samples prepared with larger HS molecular sizes. Furthermore, filtration experiments after dissolved air flotation (DAF) were carried out in an attempt to simulate conventional treatment. The most representative results in filtered water were: apparent colour ≤ 3 HU; turbidity < 0.5 NTU; and residual iron concentration < 0.005 mg/L. The absorbance and total organic carbon values of filtered water samples were also very low, suggesting that the formation of disinfection by-products with chlorine would likely be insignificant.

Tunable separations based on a molecular size effect for biomolecules by poly(ethylene glycol) gel-based capillary electrophoresis

2017 ◽  
Vol 1523 ◽  
pp. 107-113 ◽  
Author(s):  
Takuya Kubo ◽  
Naoki Nishimura ◽  
Hayato Furuta ◽  
Kei Kubota ◽  
Toyohiro Naito ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Ethylene Glycol ◽  
Size Effect ◽  
Molecular Size ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene
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