Adding Potassium Hydroxide Research Articles

Simultaneous determination of mono- and bivalent cations in environmental chemistry using isocratic ion chromatography

The influence of the pH of the mobile phase ethylenediamine (EDA)/citrate on the retention behaviour of mono- and bivalent cations on a silica based cationexchange stationary phase was studied. Variation of the pH-value was accomplished either by changing the concentration of one component of the eluent or by adding potassium hydroxide or hydrochloric acid to an eluent of fixed composition. The pH range between 2.8 and 3.0 proved to be most suitable for the separation of mono- and bivalent cations. Alkali metals, alkaline earths and transition elements could be separated in a single run. Extending the pH-range up to 5.2 showed the possibility of an additional determination of more strongly retained ions, such as Pb2+ or Sr2+.

Protein-Lipid Interactions in Concentrated Infant Formula

Radiolabeled milk proteins ([carbon-14] β-lactoglobulin or [carbon-14] κ-casein) were added to raw skim milk used to prepare concentrated humanized infant formula. Ultracentrifugation of the sterilized product allowed separation of three fractions: lipids and the proteins associated with them; free casein micelles and other dense particles; and the fluid phase. Distribution of radiolabeled tracer proteins or of protein measured by chemical methods among these three phases varied significantly with differences in processing conditions (time and temperature of sterilization) or amount of certain additives (potassium hydroxide or urea). In the range of 0 to 8 meq/L of potassium hydroxide added to the formula after homogenization but before sterilization, the lipid layer content of carbon-14 from [carbon-14] κ-casein in the sterilized product decreased by 4.7% for each 1 meq/L of added potassium hydroxide. Lipid layer content of protein decreased by 2g/L (of a total of 32g/L) for each 1 meq/L potassium hydroxide. Such differences in the structure of the product, related to interactions of protein with lipid, protein, or calcium phosphate, may correlate with physical properties and stability of milk-based lipid-rich products.

Properties of extracellular polysaccharides from Rhizobium

Extracellular polysaccharides from Rhizobium were separated into type I, isolated by precipitation with hexadecyltrimethylammonium bromide and type II, obtained by adding potassium hydroxide to the solution when no type I material was present. Total carbohydrate as glucose in the polysaccharides ranged from 21 to 92% and glucuronic acid, from 0 to 22%. Small quantities of nitrogen always remained in the samples after purification. Specific rotation values showed a wide range from −90 to +150°. Reduced specific viscosities ranged from 600 to 66,000 cm 3/g. Paper chromatographic analyses of 14 polysaccharides showed a difference between the types I and II products, particularly in the concentrations of glucose and mannose. Where several cultures within one group were tested, no direct relationships appeared evident between host legume and constituent sugars. Column electrophoretic separation of six poly-saccharides gave glucose (63–86%), galactose (14–20%), mannose (0–13%), and glucuronic acid (0–10%). Characterization results indicated as many differences within a single host legume group as between groups, suggesting that polysaccharide analysis has limited value as a diagnostic tool for classification of the Rhizobium.

Chemical states of 32P and 35S in neutron irradiated potassium chloride doped with potassium hydroxide

The distribution of 32P and 35S atoms amongst their different valency states has been studied as a function of increasing percentage of added potassium hydroxide in potassium chloride. The content of the various reduced species either changes very little or decreases in the range from 0·001 to 0·01 mol% of KOH, increases in the range from 0·01 to 0·1 mol.% of KOH and then decreases again. The different thermal annealing behaviour of species with different contents of potassium hydroxide has been also observed.

Proton magnetic resonance study of water-ammonia proton exchange in water-ammonia solutions containing added potassium hydroxide

Proton magnetic resonance study of water-ammonia proton exchange in water-ammonia solutions containing added potassium hydroxide

ヒドロキソ第一鉄錯体の空気酸化

For a better understanding of the rusting mechanism of mild steel and low alloy steels, the process of formation of α- and γ-FeOOH and Fe3O4, which are important atmospheric corrosion products of iron alloys, was investigated by infrared and Mössbauer spectra, and X-ray diffraction measurements and chlorine analysis of oxidation products of Fe(II) hydroxo-complexes.The pH-value in solution before reaction was considered as the most important factor in determining the end products of oxidation. The precipitates were prepared by adding potassium hydroxide to the oxygen free aqueous solutions containing ferrous chloride, and the oxidation of the precipitates in solution was carried out at a room temperature while blowing the air at a constant rate of 1 L/min.It was found that in the present experimental condition the process of oxidation depends on the pH-value in solution as follows: in basic solution (pH 12.5∼13.5) Fe(OH)2→α-FeOOH, in the slightly acidic solution (pH 6.0∼6.5)β-Fe2(OH)3Cl→Green Rust I→γ-FeOOH, and in neutral or slightly basic solution (pH 7.0∼8.0) Fe(OH)2→Fe3O4 and β-Fe2(OH)3 Cl→Green Rust I→Fe3O4.The infrared spectra of Fe(OH)2 and Green Rust I, an oxidation intermediate, were obtained for the first time. The strong absorption bands due to Fe(OH)2 and Green Rust I were found at 3630 and 480 cm−1, and 3540, 800 and 670 cm−1, respectively. Infrared spectroscopy was thus proved to be a powerful tool for investigation of this field.The obtained results were in good agreement with the thermodynamic considerations on the relationship between pH and the solubility of Fe(OH)2.

Kinetics of the persulphate–ferrocyanide reaction

The kinetics of the reaction between persulphate and ferrocyanide have been studied at 35°. Using glycine buffers of constant ionic strength (0·1M) in the pH range 8·2–11·6, the reaction rate is found to decrease with increase in pH, and tends towards a constant value above pH 10·8. In glycine buffers above pH 10·8, the order, as found from initial-rate measurements, is 1 with respect to persulphate and 2 with respect to ferrocyanide. In the presence of added potassium hydroxide, and also in a borate buffer (pH 11·1), the reaction is first-order in ferrocyanide. The relative effects of added alkali-metal ions in enhancing the rate lie in the order K+ > Na+ > Li+. Magnesium chloride is more effective, but this may partly rise from a change in pH. Added ferricyanide decreases the rate, but this is not due to the occurrence of the reverse reaction. Potassium chloride, potassium sulphate, and potassium citrate at the same equivalent concentration, in the presence of 0·001M-potassium hydroxide, give the same rate. On allowing for ion association, the data obtained in the presence of added potassium hydroxide fit a reaction scheme involving KS2O8– and KFe(CN)63–, as well as a postulate that a potassium ion is a necessary member of the activated complex.

A nuclear stain for Escherichia coli and related organisms.

The dye base of new fuchsin was precipitated by adding potassium hydroxide to the dye solution. The precipitate was filtered out and washed with water. It was then suspended in water, brought into solution and adjusted to a pH of about 5.0 with nitric acid. The staining solution was prepared by adding 0.3 ml. of a 14% aqueous solution of pyrogallol and 0.1 ml. of a 1% aqueous solution of boric acid to 3.0 ml. of the dye solution. Smears of cells were made in water on a slide and allowed to dry before covering with the staining solution which was also permitted to air dry. The smear was then washed in water and mordanted for 5–20 seconds in a 0.1% aqueous solution of mercuric nitrate. After rinsing in water, the smear was air dried. When dry, the slide was placed on a 50° C. warm plate for a few seconds before covering with a very thin film of a 5% aqueous solution of nigrosin which had a pH of about 5.0.