Lactic Acid Aqueous Solution Research Articles

Interaction of Alkaline Earth Metal Ions with Acetic and Lactic Acid in Aqueous Solutions Studied by 13C NMR Spectroscopy

Abstract Interaction of alkaline earth metal (magnesium, calcium, strontium and barium) ions with acetic and lactic acid in aqueous media was investigated by 13C NMR spectroscopy. In the acetate systems, signals whose chemical shifts were the averages of those of the free and bound acetate ions were observed. Downfield shifts of the carboxylate carbon signals with increasing metal ion concentration indicated that the acetate ion acted as a monodentate ligand coordinating to the metal ion using the carboxylate group. The metal ion concentration dependence of the peak positions of the methine and carboxylate carbon signals of the lactate ion in the lactate systems suggested that the lactate ion coordinated to a metal ion using the carboxylate and hydroxyl groups. Unique upfield shifts upon complexation in the magnesium lactate systems suggested that the lactate ion coordinated to the magnesium ion from outside the primary hydration sphere. The present results were consistent with the isotope effects of the alkaline earth metals observed in cation exchange chromatography.

A pilot study of lactic acid as an enamel and dentin conditioner for dentin-bonding agent development

The purpose of this pilot study was to determine how lactic acid solution at various concentrations and etching times affected prepared human enamel and dentin surfaces and to assess whether it could be used in place of phosphoric or maleic acid as an etchant. The occlusal surfaces of extracted molar teeth were ground wet with 600-grit silicon carbide paper and treated with various aqueous solutions of lactic acid. Random samples were prepared for observation by scanning electron microscopy. The rest were used to determine shear bond strength of bonded dental composite cylinders. The micrographs revealed that lactic acid dissolved the smear layer with various degrees of etching and demineralization. The degree of smear layer and matrix removal was proportional to the concentration of the acid and the length of application time. A 20% lactic acid concentration applied for 10 seconds produced a clearly etched surface with minimal demineralization. A 30% concentration not only removed the smear layer and enlarged the dentin tubule orifices but also appeared to affect the collagen matrix. The shear bond strength to enamel treated with 50% lactic acid (17.5 ± 1.5 MPa) and All-Bond 2 etchant (18.9 ± 1.3 MPa) were not significantly different ( p > 0.05). However, mean dentin bond strengths for all groups of lactic acid etchant and All-Etch etchant (10% phosphoric acid) were statistically similar.

Reaction kinetics of lactic acid with methanol catalyzed by acid resins

The esterification of aqueous lactic acid solution with methanol and its reverse reaction catalyzed by acidic cation exchange resins in the H+ form were carried out in a batch system. The inhibiting effects of water and methanol on the resins were evaluated. The experimental data were correlated by a kinetic model that the inhibition by methanol and water was included. The reaction rate constants and the adsorption coefficients were determined from the experiments. The activity of acidic resin was compared with that of sulfuric acid as catalyst. © 1996 John Wiley & Sons, Inc.

5210294 Process for the production of purified lactic acid aqueous solutions starting from fermentation broths: Giorgio Mantovani, Giuseppe Vaccari, Anna L Campi, Ferrara, Italy assigned to Himont Incorporated

5210294 Process for the production of purified lactic acid aqueous solutions starting from fermentation broths: Giorgio Mantovani, Giuseppe Vaccari, Anna L Campi, Ferrara, Italy assigned to Himont Incorporated

5210294 Process for the production of purified lactic acid aqueous solutions starting from fermentation broths: Giorgio Mantovani, Giuseppe Vaccari, Anna L Campi, Ferrara, Italy assigned to Himont Incorporated

5210294 Process for the production of purified lactic acid aqueous solutions starting from fermentation broths: Giorgio Mantovani, Giuseppe Vaccari, Anna L Campi, Ferrara, Italy assigned to Himont Incorporated

In vivo transcutaneous penetration of nicotinates and sensitive skin

Proclivity to develop irritant reactions and transcutaneous penetration of nicotinates has been investigated in 20 subjects of both sexes, divided into reactors and nonreactors on the basis of the responses to irritant stimuli. 1% sodium lauryl sulphate (patch application for 24 h) and 5% lactic acid in aqueous solutions were used to detect chemical and sensory (subjective) irritation. The vasodilatation induced was measured using a chromameter for 1 h after topical application of the chemical. The area-under-the-curve response and the peak response was used to assess the in vivo penetration of methyl nicotinate (10 mM in aqueous solution). Significant differences were found between reactors and non-reactors. Non-reactors showed a significantly decreased area-under-the-curve response and peak response to methyl nicotinate compared to reactors. Nicotinate-induced vasodilatation has been used as a model to study transcutaneous penetration of chemicals; the correlation between increased penetration of nicotinates and skin hyperreactivity to irritant substances may suggest an increased transcutaneous penetration of water-soluble chemicals in individuals with sensitive skin.

Postprandial plasma D-lactate concentrations after yogurt ingestion

The risk of D-lactic acidosis after consumption of yogurt was investigated in seven healthy volunteers. After ingestion of yogurt containing 1.06 mmol/kg body weight, D-lactic acid postprandial plasma D-lactate concentrations increased from 0.070 +/- 0.020 to a maximum of 0.200 +/- 0.010 mmol/l within 60 min. That was half the maximum concentration after the equivalent amount of D-lactate in the form of an aqueous solution of DL-lactate. The shape of the postprandial plasma D-lactate peak was flatter, but much broader after yogurt than after the aqueous solution, the peak areas being equal. When 0.64 mmol/kg body weight D-lactate were consumed as yogurt, plasma concentrations amounted to 0.086 +/- 0.030 mmol/l. Signs of a mild, transient, compensated metabolic acidosis, which was apparent in case of the aqueous lactic acid solution did not occur in case of yogurt. It is concluded that the consumption of foods containing D-lactic acid gives no reason for concern in healthy adults.

Divalent Metal Ion-Mediated Phosphodiester Bond Formation from Adenosine-5′-phosphorimidazolide with Glycolic Acid or Lactic Acid in Aqueous Solution. A Nonenzymatic Model Reaction for Nucleotidyl Transfer

Abstract Some divalent metal ions mediated in phosphodiester bond formation from adenosione-5′-phosphorimidazolide (ImpA) and glycolic acid or lactic acid giving glycolyl adenylate or lactyl adenylate. The effect of divalent metal ions on this reaction was in the order: Pb2+>Ni2+>Co2+>Zn2+>Cu2+>Mn2+>Ca2+>Mg2+>none>Hg2+. The metal ions promoted the reaction orienting the substrates and increasing the nucleophilicity of the hydroxy group of α-hydroxy acid by coordination. On the other hand, very little or no phosphodiester bond formation took place from ImpA and 3-hydroxypropionic acid or 4-hydroxybutyric acid in the presence of metal ions.

サバ筋肉中のゲル形成能低下要因について

Of various components in the muscle of Pacific mackerel, such as lipid, water soluble com-pound, lactic acid and a portion of dark tissue, the inhibiting effect on the gel forming ability of surimi were separately determined by measuring a change in jelly strength of kamaboko prepared from surimi in the presence of various amounts of those components.As the gel strength (J) of kamaboko was found to decrease exponentially with increasing amount of each component (W), the rate constant (kI) for inhibiting the development of gel strength was calculated from a slope of linear relation between log J and W. The kI values for the various factors indicated that the decreasing effect became strong in the following order; dark muscle<lipid=free water<water soluble compound<lactic acid. The addition of the corresponding amount of lactic acid aqueous solution to cause a decline in the pH of the surimi from 7.0 to 5.0 showed 100 fold decrease in the gel strength as compared with that of the same amount of free water.The irreversible decrease in the gel strength of acidified surimi with lactic acid occured largely due to lowering of the pH or prolonging the storage period.A reason for the poor gel forming ability of the muscle of Pacific mackerel was discussed in relation to various factors in its muscle.

Separation of Transplutonium and Rare-Earth Elements by Extraction with Di-isodecyl Phosphoric Acid from DTPA Solution

The distribution ratio Df and the separation factor β for Nd(III) to Am(III) were studied in DIDPA-DTPA systems to determine optimum conditions for applying DIDPA to the TALSPEAK type extraction process to separate transplutonides from lanthanoids in the partitioning of high-level waste of nuclear fuel reprocessing. Extraction of lanthanoids from 0.05–0.1 M DTPA-1 M lactic acid (pH 3.0) aqueous solution into 0.2–0.3 M DIDPA in DIPB gives the separation factor of 20 revealing practicability of this system in the partitioning. The nature of diluent affects greatly Df, and DIPB proved to be the most appropriate one for the separation of transplutonides from lanthanoids. The presence of lactic acid in the aqueous phase improved the extraction kinetics in DIDPA-DTPA system.

An Infrared Spectroscopic Investigation on the Complexes formed between Boric Acid and Lactic Acid in Aqueous Solution.

An Infrared Spectroscopic Investigation on the Complexes formed between Boric Acid and Lactic Acid in Aqueous Solution.

616. Chemical action of ionsing radiations in solution. Part XI. The action of free radicals, produced by X-rays, on lactic acid in aqueous solution with particular reference to the effect of molecular oxygen

616. Chemical action of ionsing radiations in solution. Part XI. The action of free radicals, produced by X-rays, on lactic acid in aqueous solution with particular reference to the effect of molecular oxygen

Butyric Acid and Lactic Acid in Aqueous Solutions as Solubilizers for Carcinogenic Hydrocarbons.

Butyric Acid and Lactic Acid in Aqueous Solutions as Solubilizers for Carcinogenic Hydrocarbons.

Viscosity and Density of Aqueous Lactic Acid Solutions

Viscosity and Density of Aqueous Lactic Acid Solutions