• Korean Journal of Soil Science and Fertilizer
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• v.23 no.3
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• pp.188-192
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• 1990

Sixteen amino acids in the hydrolysates of fulvic acid fraction from 7 plant materials were determined. Analyzed amino acids were aspartic acid, glutamie acid, arginine, histidine, lysine, glycine, alanine, valine, leucine, isoleusine, phenylalanine, tyrosine, serine, threonine, proline, and methionine. Four crop residues, wild grass cuttings and forest tree litters were put under investigation. 1. The content of amino acids in fulvic acid fractions extracted after 90 days of compositing ranged from 0.15% to 0.53% by dry weight. The highest value was found in the fulvic acids of wild grass cuttings and the lowest in those of wheat straw, being equivalent to 1/5-1/31 of those found in humic acids. 2. The group of neutral amino acids shared the largest portion followed by acidic and basic amino acids. 3. Arginine was not detected in fulvic acid fractions from well decomposed residues. 4. Aromatic amino acids, phenylalanine and tyrosine, were virtually absent in fulvic acid fractions. 5. Glycine, glutamic acid and aspartic acid were the 3 major amino acids contained in fulvic acids of well decomposed residues. With glutamic acid and aspartic acid excluded, the decreasing order of concentration of amino acids was roughly in parallel with the increasing order of molecular weight.

• Analytical Science and Technology
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• v.15 no.4
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• pp.373-380
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• 2002

Humic and fulvic acids present in soil of different depth were extracted and their characteristics were analyzed as a basic study to evaluate the effect of humic substances on the behaviour of radioactive elements deposited on soil. Molecular size distribution of the humic and fulvic acids was measured by stirred cell ultrafiltration technique and the structural informations were obtained from their UV-Vis., IR and synchronous fluorescence (SyF) spectral analysis. Main molecular size ranges of the soil 1) humic and fulvic acids were 30~100 kDa (46~56%) and 10~30 kDa (33~43%) respectively, and their overall molecular sizes were found to became smaller with increasing the soil depth. Absorptivities measured at 280 nm in the UV-Visible spectra of humic acids were 1.4~1.5 times higher than those of fulvic acids, and increased with increasing the soil depth. SyF spectral data showed two distinct peak components having maximum peak positions of 428 nm (type I) and 498 nm (type II) for the soil humic and fulvic acids. From the analysis of the peak components, it was found that humic molecules are mainly made up of aromatic compounds corresponding to longer wavelength (type II), and the molecular components increased with increasing the soil depth. Analysis of IR spectral data indicated that the humic molecules contain a higher relative concentration of carboxylic groups than those of fulvic molecules, and the carboxylic group contents are seen to increase as the soil depth increase.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.397-400
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• 2003

In this study, humic and fulvic acids in soils at the vicinity of domestic atomic power plants(NPPs), located in Yungkwang(YK), Uljin(UJ), Kori(KR), Koseong(KS), Wolseong(WS) area, and in volcanic ash soils of the Cheju island(Mt. Hanla(HL), Manjanggul(MJ)) were isolated, and characterized using chemical(elemental analysis, proton exchange capacity, molecular size distribution) and spectroscopic(UV/Vis., IR, FL, $^{13}$ C NMR spectra) methods. The results were compared with one another and compiled for their DB establishments. The humic substances distribution (humic acid, fulvic acid, Humin) in the soils were also determined by IHSS standard method. Main purpose of this study was to provide a basic data needed to evaluate the effect of humic substances on the migrational behaviour of radioactive elements in contaminated surface soil.

• Near Infrared Analysis
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• v.1 no.1
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• pp.31-35
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• 2000

Near-infrared reflectance spectroscopy(NIRS) was used to determine the humic acids in soil samples from the fields of different crops and land-use over Youngnam and Honam regions in Korea. An InfraAlyzer 500 scanning spectrophotometer was obtained near infrared relectance spectra of soil at 2-nm intervals from 1100 to 2500nm. Multiple linear regression(MLR) or partial least square regression (PLSR) was used to evaluate a NIRS method for the rapid and nondestructive determination of humic acid, fulvic acid and its total contents in soils. The raw spectral data(log 1/R) can be used for estimating humic acid, fulvic acid and its total contents in soil by MLR procedure between the content of a given constituent and the spectral response of several bands. In which the predicted results for fulvic acid is the best in the constituents. The new spectral data are converted from the raw spectra by PLSR method such as the first derivative of each spectrum can also be used to predict humic acid and fulvic acid of the soil samples. A low SEC, SEP and a high coefficient of correlation in the calibration and validation stages enable selection of the best manipulation. But a simple calibration and prediction method for determining humic acid and fulvic acid should be selected under similar accuracy and precision of prediction. NIRS technique may be an effective method for rapid and nondestructive determination for humic acid, fulvic acid and its total contents in soils.

• Analytical Science and Technology
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• v.16 no.4
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• pp.283-291
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• 2003

Humic and fulvic acids present in soils of different depth were extracted and their acidic functional groups and structural characteristics were analyzed and compared. The purpose of this study was to present a basic data needed to evaluate the effect of humic substances on depth distribution and migrational behaviour of radioactive elements deposited on soil. Acidic functional groups of the humic and fulvic acids were analyzed by pH titration method, and their proton exchange capacity (PEC, $mq\;g^{-1}$) and average $pK_a$ values were obtained. Structural characteristics of the humic and fulvic acids were analyzed using their CPMAS $^{13}C$ NMR spectra and elemental composition data. pH titration data showed that fulvic acids have higher acidic functional group contents ranging from 5.5 to $7.0meq\;g^{-1}$ compared with that of humic acids ($3.8{\sim}4.8meq\;g^{-1}$). From depth profiles, it has been found that PEC values of humic acids in deeper soil (> 8 cm) were higher than those at the surface soils. Elemental compositions (H/C ratio) and spectral features ($C_{arom}/C_{aliph}$ ratio) obtained from CPMAS $^{13}C$ NMR spectra showed that the aromatic character in humic acids was a relatively higher than that of fulvic acids, while lower in carboxyl carbon content. The aromatic character and carboxyl carbon contents of humic acids tend to increase as soil depth increased, but those of fulvic acid showed little differences by the soil depth range.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.341-349
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• 1987

Fulvic acids extracted from seven plant materials were tested. The IR spectra and the data obtained from chemical analyses in terms of oxygen-containing functional groups complemented one another. Selected samples covered straws of grain crops (rice, barley, wheat and rye), hay of wild grass, and leaves of trees (deciduous and coniferous). 1. No significant variation in IR spectra of fulvic acids was observed among samples taken from different plant residues and at different stages of humification. 2. Oxygen-containing functional goups, such as carboxyls, phenolics, alcoholics, carbonyls, and quinones were identified on IR spectra and confirmed by chemical analyses. 3. The acidity of fulvic acids was directly related with the content of carboxyl groups. 4. Alcoholic hydroxyl groups predominated over phenolic hydroxyls. 5. The major part of fulvic acid structure appeared to be strongly aliphatic in many respects of chemical characteristics.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.44-52
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• 1996

Humic substances of 17 organic fertilizers available on the market were the objects of study. The list of ingredients for formulation of them comprised fish meal. bone meal, oil-cakes, brewer's grains, peat, sawdust, wood bark, zeolite, soil conditioner, live-stock droppings, amino acid fermentation byproduct, chaff, limestone and others. Humic and fulvic acids were isolated from those substances and given chemical and spectroscopic analyses. Nutritional values of the organic fertilizers showed big diversity. Humification of organic matter was incomplete for some of the fertilizers as indicated by a high C/N ratio. Extractable humic acid percentage was higher, in general, than that of fulvic acid. Also the relative content of humin increased with advanced humification. Total acidity was closely related to phenolic hydroxyl groups. Relationships between carboxyl and hydroxyl groups. and carboxyl and alcoholic hydroxyl groups were very significant. Ultraviolet and visible light absorption spectra of humic and fulvic acids were substantially similar. The types of humic acids were B. P, and Rp. Two humic acids of the 17 samples belonged to B type. 3 to P type and all the rest to Rp type.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.777-781
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• 1994

Three humic acids (HA) and one fulvic acid (FA) are extracted from soils of the Okch'on Basin (Koyesan, Yongkwang and Taejon), and are purified and characterized using $^1H,\;^{13}C$ NMR, and IR spectroscopic methods. The results are compared with one another and with commerical humic acid (Aldrich Co) and aquatic humic acid from Gorleben underground aquifer in Germany. The IR and $^1H\;and\;^{13}C$ NMR spectral features are found to be nearly identical, suggesting that humic substances formed in the Okch'on Basin have quite similar chemical properties. These humic substances from Okch'on Basin soils have undergone low degree of aromatic condensation and have high contents of aliphatic functionalities including carbohydrates.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.254-263
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• 1988

Contents and distribution of amino acids in the humic acid and fulvic acid fractions of different types ($R_p$, B, A, P) were investigated. Extracted humic and fulvic acids were purified and analyzed. The results are summarized as the following: (1) Composition of Humus The total humus ($H_T$), amount of humic acid (a), amount of fulvic acid (b), and ${\Delta}logK$ all decrease in the order of $R_p$ > B > A > P type. The same trend was observed in the total nitrogen and carbon. (2) Contents and composition of amino acids in humic acids. 1) The total amounts of amino acids in the humic acid fraction of different types were in the following order for soils under coniferous forest trees: $R_p$ > B > A > P type, but for soils under deciduous forest trees the order was P > A > $R_p$ > B type. There were positive correlationships between total amino acids and total carbon and ${\Delta}logK$ for humic acids from soils under coniferous forest trees, but a negative correlationship was existed. between total amino acids and C/N ratios. No significant correlation was found for samples taken from soils under deciduous forest trees. 2) The ratios of one group of amino acids to the others were compared. The ratios of acidic amino acids were in the order of P > $R_p$ > B > A type. those of neutral amino acids followed the order of $R_p$ > B > A > P type and those of the basic amino acids were in the order of B > A >$R_p$ > P type for soils under coniferous forest trees. Contents of total amino acids were in the order of the neutral > the acidic > the basic amino acids. For the soils under deciduous forest trees the order of the ratio was different. Acidic amino acids followed the order of A > P > B > $R_p$ type, neutral ones followed the order of P > $R_p$ > A > B type, and the basic amino acids did the order of $$P{\geq_-}$$ A > B $$\geq_-$$ $-R_p$ type where the difference was very small. 3) In general aspartic aicd, glycine and glutamic acid were the major components in all samples. Histidine, tyrosine and methionine belonged to the group contained in a small amount. (3) Contents and composition of amino acids in fulvic acids. 1) The total amounts of amino acids of different types of fulvic acids were in the order of $R_p$ > B > P > A type regardless of origin of samples. There were positive correlationships observed between the toal amino acids and total carbon and ${\Delta}logK$ for soils under coniferous forest trees. For soils under deciduous forest trees, positive correlationships were observed among total amino aicds, total nitrogen, total humus ($H_T$), total humic aicd (a), and ${\Delta}logK$, but a negative correlationship existed between total amino acids and C/N ratio. 2) Thr ratio among acidic amino acids, neutral amino acids and basic amino acids of different types were $R_p$ > B > P > A type. In this respect there was no difference between the two soils. 3) In general glycine, aspartic acid, and alanine were the major constituents in all samples of different types, while tyrosine and methionine were contained in a small amount. Virtually no amount of arginine was measured.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1067-1074
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• 2008

In this study, the organic carbon normalized-sorption coefficients (Koc) for the binding affinity of phenanthrene (PHE) to 16 different soil humic and fulvic acids of various origins were determined by fluorescence quenching. The humic and fulvic acids used in this study were isolated from 6 different domestic soils including Mt. Hanla soil, IHSS standard soil and peat as well as Aldrich humic acid and characterized by elemental composition, ultraviolet absorption at 254 nm, composition of main structural fragments determined by CPMAS $^{13}$C NMR. The Koc values($\times$10$^4$, L/kg C) for each of HA and FA samples were in the range of 1.48$\sim$8.65 and higher in HA compared to that of FA(3.13$\sim$8.65 vs 1.48$\sim$2.48) in the experimental condition([PHE]/[HS] = 0.02$\sim$0.2(mg/L)/(mg-OC/L), pH 6). The correlation study between the structural descriptors of humic and fulvic acids and log Koc values of phenanthrene, show that the magnitude of Koc values positively correlated with the UV$_{254}$ absorptivity([ABS]$_{254}$) and two $^{13}$C NMR descriptors (C$_{Ar-H,C}$, $\sum$C$_{Ar}$/$\sum$C$_{Alk}$), while negatively correlated with the independent descriptors of the(N+O)/C atomic ratios and $^{13}$C NMR descriptors (I$_{C-O}$/I$_{C-H,C}$). These results confirmed that the binding affinity for the hydrophobic organic compound, phenanthrene are significantly influenced by the polarity and aromaticity of soil humc and fulvic acids.