The Acid Behavior of Pectinic Acids

Speiser, R.; Hills, Claude H.; Eddy, C. Roland

doi:10.1021/j150442a006

Cited by 35 publications

(11 citation statements)

References 24 publications

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“…The slightly different elution behavior of GalA oligomers, when compared to glucose oligomers of the same size (e.g., for glc 4 (6.0 min) and GalA 4 (5.3 min)) can be explained by the fact that at pH 2.98, still a small part of the carboxylic acid groups on GalA are dissociated [55,56]. The average sum of these residual charges could explain the shorter migration times.…”

Section: Influence Of Ph On the Separation Of Pectin Oligomers With Cmentioning

confidence: 98%

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CE‐MSⁿ of complex pectin‐derived oligomers

Coenen¹,

Kabel²,

Schols³

et al. 2008

Electrophoresis

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As pectin molecules are too large and heterogeneous to analyze as a whole, the polymer is usually degraded to smaller oligomers, which are often analyzed by high-performance anion exchange chromatography (HPAEC). However, the high salt concentration necessary to elute pectin oligomers by HPAEC is incompatible with online mass detection. To overcome such a disadvantage, a CE-IT-MS system was set up to further elucidate the fine structure of charged oligosaccharides. An effective separation of differently substituted galacturonic acid containing oligomers was obtained by low-pH CE-LIF analysis. By adapting the buffer and capillary online MS detection was enabled. Moreover, with MS/MS it was possible to localize sugar residues' substitutions. With this combined CE-MS approach LIF electropherograms of xylogalacturonan and rhamnogalacturonan I digests could be annotated. The method was further exemplified by a complex oligomer mixture of acid hydrolyzed apple pectin, which was separated and characterized by CE-MSn. Oligomers present in low amounts could be localized by their corresponding m/z, as was demonstrated by selected mass range representation.

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Section: Influence Of Ph On the Separation Of Pectin Oligomers With Cmentioning

confidence: 98%

“…Galacturonic acids have a pK a of ,3.6 [55,56], therefore CE was performed at standard conditions of the Beckman CE kit (pH 4.75) and at conditions below the pK a of GalA (pH 2.98), where the carboxyl group would be predominantly charged, respectively mainly uncharged.…”

Section: Influence Of Ph On the Separation Of Pectin Oligomers With Cmentioning

confidence: 99%

CE‐MSⁿ of complex pectin‐derived oligomers

Coenen¹,

Kabel²,

Schols³

et al. 2008

Electrophoresis

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“…This observation is in accordance with the range of K, values between 10-4 and 10-5 found by Speiser et a1. 21 (R = ion exchanger) the pH decreases, causing a drop in capacity of the cation exchanger. If it is desired to remove Sr++ from a concentrated solution of this ion, a buffering salt like Sr(HS)e, mentioned above, During the exchange reaction: 2RH + Sr+ + ReSr + 2H+ must be chosen.…”

Section: Selectivitymentioning

confidence: 99%

“…Speiser et a1. 21 found a range of Kz values from 3 . 3 0~ 10-4 to 1-23 x 10-5 for a pectin in which 10 per cent of the carboxyl groups present were esterified.…”

Section: Introductionmentioning

confidence: 99%

Cation exchangers on a sugar‐beet pulp base. Application for decontaminating radioactive waste water

Langenhorst

Tels

Vlugter

et al. 1961

Biotechnol. Bioeng.

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Summary.A cation exchanger suitable for decontaminating low and medium radioactive waste water was sought. Regeneration being considered undesirable, the exchange material had to be cheap and readily obtainable. Sugar-beet pulp, a weakly acidic cation exchanger, satisfies these conditions. Its capacity is about 0.62 mg eq. per gram of dry matter. I n order to study the selectivity of the sugar-beet pulp exchanger, the equilibrium curve of the reaction 2 RNa + Sr++ + RzSr + 2 Na+ (R = ion exchanger) was determined.This curve was found to have the shape of the hyperbola proposed by Waterman and Weber for the characterization of the course of simultaneous reactions. Sugar-beet pulp adsorbs the salts of the alkaline earth metals selectively in the presence of both Na+ and La+++. Sugar-beet pulp was used to decontaminate a solution containing 140BaC12 and 140LaC13 and having an activity of about 10-2 pc/ml.By treating sugar-beet pulp with formaldehyde and hydrochloric acid, the amount of water bound to the pulp is very much decreased. By this treatment a cation exchanger is produced having a capacity per unit volume about six times greater than that of sugar-beet pulp. The capacity of this exchanger is about 0.5 mg eq. per gram of dry matter. The selective behaviour of sugar-beet pulp treated with formaldehyde is similar to that of unmodified sugar-beet pulp.By treating sugar-beet pulp with formaldehyde, hydrochloric acid and dilute sulphuric acid, a cation exchanger with very good mechanical and filtration properties is obtained. This exchanger has a capacity of about 1.3 mg eq. per gram of dry matter.It seems possible to employ the cation exchangers obtained by treatment of sugar-beet pulp with either formaldehyde and HC1 or formaldehyde, HCl and HzSO4 also for purposes other than the removal of radioactive cations from water. 7The results were satisfactory. 8 U'. TH. J. P. LAXGENHORST et al.

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“…UsWe present here an application of the AOD-POD-ABTS procedure to continuously determine the release ing a titrimetric assay at the optimum pH of pectinesterase corrections must be made for partial dissociation of methanol from pectin by pectinesterase and we describe its use to determine pectin or pectinesterase levof the liberated carboxyl groups, whose pK values vary with the concentration of the pectin, the degree of ester-els. Under the conditions of this assay, the equilibrium constants for the enzymatic reactions involved in this ification, and the mode of deesterification (8).…”

mentioning

confidence: 99%