ATRAZINE HYDROLYSIS IN SOILS: CATALYSIS BY THE ACIDIC FUNCTIONAL GROUPS OF FULVIC ACID

1985 ◽  
Vol 65 (3) ◽  
pp. 435-443 ◽  
Author(s):  
DONALD S. GAMBLE ◽  
SHAHAMAT U. KHAN
Keyword(s):  
Fulvic Acid ◽  
Functional Groups ◽  
Natural Waters ◽  
Acid Catalysis ◽  
Carboxyl Groups ◽  
Acid Solutions ◽  
Predictive Equation ◽  
Hydrogen Ions ◽  
Soil Solutions ◽  
Humic Materials

The catalysis of atrazine hydrolysis at 25.0 °C by the types of acidic functional groups found in humic materials has been investigated. No evidence of catalysis by carboxylate ions was observed. From a knowledge of the types and numbers of acid functional groups in a quantitatively characterized fulvic acid, and the distributions of their KA values it was found that hydrogen ions and undissociated carboxyl groups were the only catalytic agents. The carboxyl groups have a second-order kAH of 7.88 days −1∙M−1. Weakly acidic functional groups having [Formula: see text]showed no catalysis. A predictive equation has been produced for the half-life of atrazine in fulvic acid solutions at 25.0 °C. It represents a general class of equations which should permit the practical prediction of atrazine persistence in soil solutions and other natural waters. Key words: Atrazine hydrolysis, atrazine persistence, fulvic acid, fulvic acid carboxyls, acid catalysis, carboxyl catalysis

Methods for the comparison of fulvic acid samples: the effects of origin and concentration on acidic properties

1978 ◽  
Vol 56 (9) ◽  
pp. 1196-1201 ◽  
Author(s):  
R. Douglas Burch ◽  
Cooper H. Langford ◽  
Donald S. Gamble
Keyword(s):  
Fulvic Acid ◽  
Functional Groups ◽  
Weighted Average ◽  
Chemical Characteristics ◽  
Acid Solutions ◽  
Concentration Change ◽  
Acidic Properties ◽  
General Chemical ◽  
Equilibrium Function ◽  
Definition Of

The principles according to which the acidic properties of fulvic acid solutions should be compared are demonstrated. An equilibrium function defined and measured for any mixture, including fulvic acid functional groups, will be a weighted average. A concentration change will generally affect this average by changing the relative values of the statistical weights. Concentration corrections are therefore required for the comparison of two fulvic acid solutions. A Chernozem Ah fulvic acid and the previously described Armadale fulvic acid Batch FA1 were examined in this way. They were found to have the same general chemical characteristics, but with somewhat different numerical values. The implications of these results for the definition of fulvic acid are considered.

Potentiometric Titration of Fulvic Acid: Equivalence Point Calculations and Acidic Functional Groups

1972 ◽  
Vol 50 (16) ◽  
pp. 2680-2690 ◽  
Author(s):  
Donald S. Gamble
Keyword(s):  
Fulvic Acid ◽  
Potentiometric Titration ◽  
Functional Groups ◽  
Acid Dissociation ◽  
Carboxyl Groups ◽  
Chemical Information ◽  
Equivalence Point ◽  
Iterative Calculation ◽  
Detailed Chemical

Gran's functions corrected for buffering and H2O dissociation have been incorporated into the iterative calculation for the two equivalence points and the acid dissociation equilibria. The experimental and mathematical conditions required for accurate, dependable operation of the method have been examined. The resulting equivalence point calculations are based directly on a chemical interpretation of the system, without approximations. The first equivalence point is shigher than previously reported, and is displaced upward by KCl. Detailed chemical information has been obtained for some of the acidic functional groups, from plots of KA = (mHδmA/δmAH) vs. mequiv./g. Carboxyl groups at the chelating sites are essentially all ionized for H+ concentrations less than 1 × 10−5 m.

scholarly journals Obtaining humic materials by mechanochemical reduction

2021 ◽  
Vol 340 ◽  
pp. 01001
Author(s):  
Natalya Yudina ◽  
Elizaveta Linkevich ◽  
Anna Saveleva ◽  
Oleg Lomovsky
Keyword(s):  
Mechanical Activation ◽  
Functional Groups ◽  
Fulvic Acids ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Humic And Fulvic Acids ◽  
Humic Materials ◽  
Spectral Coefficients ◽  
Mechanochemical Modification

In the study, a mechanochemical modification of peat was carried out, leading to an increase in the number of functional groups and an increase in the solubility of humic complexes with metals. It was shown that the mechanical activation of peat in the presence of Zn significantly increased the yield of extractable fulvic acids. An analysis of the spectral coefficients showed that humic and fulvic acids extracted from peat were characterized by an increased content of alcohol hydroxyl groups, C–O carbohydrate moieties, and carboxyl groups.

Design and Use of Background-Reduced 27Al NMR Probes for the Study of Dilute Samples from the Environment

1995 ◽  
Vol 49 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Janet S. MacFall ◽  
Anthony A. Ribeiro ◽  
Gary P. Cofer ◽  
Ko-Hsiu G. Dai ◽  
William Labiosa ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Natural Waters ◽  
Background Signal ◽  
27Al Nmr ◽  
Sample Container ◽  
Al Content ◽  
Free Sample ◽  
External Reference ◽  
Soil Solutions ◽  
Colorimetric Assays

Development of methods for the detection and measurement of aluminum (Al) is crucial for our understanding of Al(III) chemistry and toxicity in natural waters, soil solutions, and environmental samples. Traditional colorimetric assays, by their very nature, alter solution Al(III) chemistry, potentially biasing measurements. Methods based on 27Al NMR spectroscopy have the advantage of being nondestructive and of not altering the chemistry of the solution. Standard commercial NMR probes and sample tubes, unfortunately, are constructed from aluminum-containing components. These materials give substantial background signal, which is detected as a large, broad hump, overwhelming signals from dilute samples. We describe here the construction of two novel NMR probes and a sample container built from a variety of materials with low Al content. The designs feature the use of transversely mounted solenoid coils with aluminum-free sample holders. The sample container features a second chamber which can be filled with an external reference solution. These novel 27Al NMR probes are being used for the NMR spectroscopic investigation and quantitation of natural, dilute (10−6 M) Al(III) samples from the environment.

scholarly journals Self assembled nanocages from DNA–protoporphyrin hybrid molecules

RSC Advances ◽  
2015 ◽  
Vol 5 (108) ◽  
pp. 89025-89029 ◽  
Author(s):  
Vandana Singh ◽  
Mohan Monisha ◽  
Roy Anindya ◽  
Prolay Das
Keyword(s):  
Functional Groups ◽  
Protoporphyrin Ix ◽  
Building Blocks ◽  
Carboxyl Groups ◽  
Dna Oligomers ◽  
Organic Hybrid ◽  
Molecular Building Blocks ◽  
Modified Dna ◽  
Hybrid Molecules ◽  
Self Assembled

DNA–organic hybrid molecular building blocks are generated by covalent conjugation of the carboxyl groups of protoporphyrin IX with the amine functional groups of modified DNA oligomers.

Identification of trihaloacetaldehydes in ozonated and chlorinated fulvic acid solutions

The Analyst ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 71 ◽  
Author(s):  
Yuefeng Xie ◽  
David A. Reckhow
Keyword(s):  
Fulvic Acid ◽  
Acid Solutions

scholarly journals The binding of hydrogen ions to an acidic glycoprotein from bovine cortical bone

1967 ◽  
Vol 105 (3) ◽  
pp. 1171-1175 ◽  
Author(s):  
A. R. Peacocke ◽  
P A Williams
Keyword(s):  
Sodium Chloride ◽  
Glutamic Acid ◽  
Titration Curve ◽  
Analytical Data ◽  
Total Content ◽  
Bone Sialoprotein ◽  
Model Systems ◽  
Carboxyl Groups ◽  
Hydrogen Ions ◽  
Titration Curves

The H+ ion dissociation of bone sialoprotein in 0·2m-sodium chloride at 25° was studied. The total content of carboxyl groups available for titration was calculated by comparing the titration curve with the titration curves of three model systems and by the use of analytical data. This comparison showed that 7·0 carboxyl groups/mol. do not participate in the titration, and it is proposed that these are aspartic acid or glutamic acid carboxyl groups present as amides; this is also indicated by titration of the sialoprotein after acid hydrolysis. The titration of carboxyl groups was found to agree well with the Linderstrøm-Lang equation for spherical macroions.

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