Sodium pyrophosphate , humic

Humic acids are alkaH-extractable materials and total humic acid content is a term that refers to the humic acid content of coal that has had its carboxylate cations removed with sodium pyrophosphate. Values for some typical AustraHan brown coals range from 24—92% (13). Treatment of lignitic coals with mineral acid to release the alkaH and alkaline cations may dissolve up to 20% of the coal. The naturally moist coals are slightly acidic and have a pH of 3.5—6.5. 

Pontanen and Morris [8] compared the structure of humic acids from marine sediments and degraded diatoms by infrared and C13 and proton NMR spectroscopy. Samples of marine sediments taken from the Peru continental shelf were extracted with water, sodium hydroxide (0.05mol 1 J) and sodium pyrophosphate (0.05mol l-1) under an atmosphere of nitrogen and fractionated by ultrafiltration. Humic acids of molecular weight 300000 and above were examined. Diatoms were collected from... 

Randle and Hartman [12] used thermal neutron activation in analysis to investigate total bromine in humic compounds in soil. Bromine was extracted from the soil water with sodium hydroxide or sodium pyrophosphate, then the extract dried prior to analysis. 

Aqueous samples are treated similarly beginning with the acidification step. The entire sample is then put through the hydrophobic resin, and the fulvic acids are eluted at pH 7. The humic acids are removed with 0.1 M NaOH (2). After extraction, purification of the samples can be accomplished by freeze-drying and dialysis. The use of strong acids and bases has been criticized for several reasons. They can promote degradation, decarboxylation, oxidation, and condensation reactions. Strong acids and bases can also dissolve siliceous materials and lyse cells, resulting in contamination of the sample. Other extractants have been proposed, such as sodium pyrophosphate or sodium fluoride however, the classical procedure offers the most complete dissolution of humic material from solid samples and is still most often used (72). 

Attempts at characterizing peat humus through spectroscopy and chemical degradation procedures (Walmsley, 1973 Stevenson, 1974 Fuchsman, 1980) also have shown that peat humic substances are similar to those from mineral soils. For example Levesque et al. (1980b) found that humic substances extracted by sodium pyrophosphate from 10 different peat materials that varied in botanical origin and extent of humification yielded aliphatic and phenolic compounds and benzenecarboxylic acids (Table 14) in amounts... 

Tables 8 and 9 present data for extraction of humic substances from a sapric histosol and from two tropical soils using various combinations of DMSO, acid, and water. For comparison, some data are presented for solution in sodium hydroxide and neutral sodium pyrophosphate solutions. Use is made of EJEf, ratios to indicate differences in the solution conformations and/or compositions of the humic substances in the different solvent systems.

Alexandrova, L. N. (I960). The use of sodium pyrophosphate for isolating free humic substances and their organic-mineral compounds from the soil. Soviet Soil Sci. 2, 190-197. 

Figure 5. Isotherms of 1,3-dichlorobenzene in whole Pahokee peat soil (ATp = 340, N =0.8501) and its derivatives, humin (K = 464, N =0.7662) and humic acid ( p = 161, AT =0.936). Equilibration period, 48 h. The soil was extracted with sodium pyrophosphate. Adapted from data in ref. 11.

The presence of large proportions of nonhumified material of diverse origins and properties hampers the dissolution, fractionation, and estimation of humic substances in peatlands. No satisfactory methods exist for these purposes. Most studies of peat humus therefore focus on pyrophosphate extracts or humic acids obtained by sodium hydroxide extraction. 

Disodium manganous EDTA 5-Dodecyl salicylaldoxime Hexamethylene diamine tetra (methylene phosphonate) Humic acid 2-Hydroxy-5-nonylacetophenone oxime 4,4 -lsopropylidenediphenol alkyl (C12-15) phosphites Laureth-9 phosphate Lauroyl lysine Nitrosophenylhydroxylamine ammonium salt Potassium acid saccharate Sodium acid pyrophosphate Sodium cyanide Sodium N-hydroxyethylglycine Sodium polydimethylglycinophenolsulfonate Sodium sarcosinate... 

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