Concentration Of Orthophosphoric Acid Research Articles

Surface phenomena and electrochemical behavior of phosphate ion incorporated titania nanotubes for boosting bone cell growth

The addition of bone-native calcium and phosphate ions to implant materials can improve biocompatibility. The objective of the work was a comprehensive analysis of phosphate incorporation in nanotubes utilising orthophosphoric acid as the electrolyte and its effect on nanotube development during anodization process. Also, the material’s biological compatibility was investigated. A traditional anodization method was utilised to create nanotubes on commercially pure titanium (Cp-Ti) metal surfaces. The creation of nanotubes was detected at an optimal concentration of orthophosphoric acid, while other experimental variables such as voltage, time, temperature, etc. were maintained constant. The surface phenomena of anodized TIOP’s were examined through High-resolution scanning electron microscopy (HR-SEM), X-ray diffraction (XRD) analyser and contact angle. Fourier transform RAMAN study validated the penetration of phosphate ions into nanotubes. Potentiodynamic polarisation investigation in SBF was used to analyse the corrosion behaviour of anodized TIOP’s surface and Scanning Electrochemical Microscopy (SECM) mapped the reactive surface of the anodic oxide layer. The biomineralization studies were performed for 14 days in SBF and analysed with SEM/EDX and ATR-FTIR. The cell compatibility of the anodized sample surface was carried out in the MG63 cell line. The result indicated the addition of bone-native phosphate ions to anodized surface influences the differentiation of cells. The apatite formations on anodized surface influence the corrosion behaviour of the sample and result in high corrosion resistance in SBF.

Quality assessment and analytical quality by design-driven RP-HPLC method development for estimation of Gymnemagenin in Gymnema sylvestre

Gymnemic acids are the group of phytocompounds from Gymnema sylvestre known to possess hypoglycemic activity. Quantitative estimation of Gymnemic acid in terms of Gymnemagenin is essential for the standardization of G. sylvestre. In the present work, methodology combining reversed-phase HPLC with an Analytical Quality by-design approach was utilized for quantitative analysis of Gymnemagenin in G. sylvestre leaves. The quality assessment was performed by evaluating various pharmacognostic parameters as per WHO guidelines. Initially, the Analytical Target Profile and Critical Quality Attributes were identified. The method was optimized using 22 full factorial designs with a concentration of orthophosphoric acid in the aqueous phase (X1) and mobile phase ratio (X2) selected as an independent variable and, tailing factor (R1) and theoretical plates (R2) chosen as dependent variables. The optimized chromatographic conditions were identified with mobile phase, Methanol and Water (0.1% OPA) in the ratio of 85:15 v/v with flow rate of 0.8 mL/min and detection wavelength of 210 nm. Further, the amount of Gymnemagenin in crude G. sylvestre leaves and its extract was found to be 5.108% and 6.23% w/w respectively. The quality evaluation parameters were found to be within the given standard limit. Finally, it can be concluded that the combination of the HPLC method with the AQbD approach resulted in a more precise and accurate method for quantification of total Gymnemic acids in terms of Gymnemagenin. The developed method involves advantages such as efficient separation, well-defined peaks, and reduced analytical time and can be successfully applied for the analysis of Gymnemagenin in different Gymnema species and their herbal products.

Experimental and theoretical studies for corrosion of molybdenum electrode using streptomycin drug in phosphoric acid medium

Corrosion inhibition of molybdenum electrode in H3PO4 acid medium of different concentrations (3.0 to 13 M) has been investigated utilizing different electrochemical techniques. It was observed that the most corrosive concentration is 3.0 M orthophosphoric acid concentration. The effect of adding Cl− to 3.0 M orthophosphoric acid in the concentration range of 0.1 to 1.0 M was also studied. This study showed that the most corrosive medium is 3.0 M containing 1.0 M chloride ion with the greatest rate of hydrogen production. In 3.0 M H3PO4 acid with 1.0 M of NaCl, the tested electrode's corrosion and hydrogen production may be successfully suppressed by adding Streptomycin of 10 mM concentration leading to high inhibition efficiency. The outcomes of the studies were confirmed by scanning electron microscopic examination. Additionally, a computational chemistry approach was used to investigate how streptomycin adsorbs and inhibits corrosion at the interface of metal surfaces, and the outcomes of the computational studies are in excellent accord with the experimental findings.

The effect of orthophosphoric acid on energy-intensive parameters of porous carbon electrode materials.

The effect of orthophosphoric acid concentration as an activating agent on the porous structure of carbon materials derived from apricot pits and energy-intensive parameters of electrochemical capacitors formed on their basis is studied. It is found that changing the ratio of the mass of the activating agent to the mass of the raw material in acid-activated porous carbon materials (PCMs), one can control the pore size distribution in the range of 0.5-20 nm and specific surface area in the range of 775-1830 m2/g. The use of cyclic voltammetry, impedance spectroscopy and chronopotentiometry made it possible to set the capacitive nature of charge accumulation processes in acid-activated PCMs, as well as to determine the contribution of a certain size of pores to the specific capacitance of PCM/electrolyte system.

Quality assessment and RP-HPLC method development for estimation of curcuminoids in Curcuma longa: A Quality by Design approach

The present work aims at developing a QbD assisted RP-HPLC method for the estimation of individual curcuminoids in Curcuma longa rhizomes along with its quality assessment. The quality of crude C. longa sample was evaluated with respect to physicochemical, phytochemical and toxic contaminant analysis. The ATP and CQA’s were identified followed by the optimization of the method by employing 22 factorial design. The concentration of orthophosphoric acid in aqueous phase (X1) and mobile phase ratio (X2) were selected as independent variable whereas, Tailing factor CUR (R1), peak width CUR (R2), Tailing factor DMC (R3), peak width DMC (R4), Tailing factor BDC (R5), and peak width BDC (R6) selected as dependent variables. The optimized chromatographic conditions were identified with mobile phase, Acetonitrile and Water (0.02%OPA) in the ratio of 55:44 with flow rate of 1 mL/min and detection wavelength of 425 nm. Further, the amount of curcumin, demethoxycurcumin and bis-demethoxycurcumin in crude C. longa sample was found to be 13.86 ± 0.28, 10.98 ± 0.23 and 9.32 ± 0.20 mg/g respectively. From the results obtained it can be concluded that the application of the QbD approach ensured the development of a more precise method that can engender consistent, reliable, and quality data throughout the process and also save time.

Analytical QbD: Designing Space for HPLC Method Operable Region for Estimation of Preservatives in Herbal Formulation

Background: Quantification of preservatives in herbal formulation, simultaneously by high performance liquid chromatography analysis is very complex and involves series of steps including sample preparation, selection of suitable mobile phase and its validation for routine applications. </P><P> Introduction: Application of Quality by Design (QbD) in the development of novel, simple, accurate and precise RP-HPLC method for concurrent quantification of quaternary preservatives in herbal formulation, focusses on development of robust method. Methods: Isocratic analysis was carried out using C18 column at 231 nm. Risk assessment studies were executed to determine the critical method parameters which were defined as acetonitrile volume in the mobile phase, volume of injection and orthophosphoric acid concentration in the mobile phase. The effect of the critical method parameters on critical method attributes, i.e. retention time, resolution and chromatographic optimization function was further evaluated by means of central composite design and the optimal conditions were determined through derringer’s desirability approach of multi-criteria decision making technique. Results: The method was statistically validated according to ICH guidelines having good resolution using optimized mobile phase, acetonitrile: 0.11% orthophosphoric acid in water (12.30: 87.70 % v/v) giving acceptable retention time i.e. 3.7128 ± 0.0138 of bronopol, 4.5106 ± 0.00542 of sodium propyl paraben, 10.7228 ± 0.029 of sodium benzoate and 12.252 ± 0.027 of sodium methyl paraben. Conclusion: Hence, the QbD based method development assisted in generating a design space with knowledge of all method performance characteristics leading to a better understanding of the method, and achieving desirable method quality.

The destructive effect of strong concentrations of orthophosphate acid in an acid detergent disinfectant on elements of milking equipment made of stainless steel and aluminum

A huge part of the milking equipment and milk dishes are made of stainless steel and aluminum. Under certain conditions, the influence of such factors as the atmosphere, water, milk, and chemical agents leads to the destruction of metal working surfaces of the milking equipment, resulting in a shorter period of their exploitation. On damaged sites the milk remains are left, that is actually a good nutrient medium, resulting in the creation of conditions for the active development of the microflora. As a result, the following process leads to a marked reduction in disinfectant effect when sanitized. The object of this work was to investigate the influence of various concentrations of orthophosphate acid in an acid detergent disinfectant on the elements of the milking equipment made of stainless steel and aluminum. Accordingly, the result of the conducted research showed that the orthophosphate acid of all four experimental concentrations (20, 25, 30, 35%) in the acid detergent showed a slight destructive effect on stainless steel and was within the standard of corrosion value up to 2 g/m2/year. The increase in the concentration of orthophosphate acid caused a growth in the amount of destruction of stainless steel, which was the highest in the concentration of 35% and amounted to 0.326 g/m2/year. The rate of destruction of stainless steel was in the range from 0.895 ± 0.0036 to 1.712 ± 0.0031 mg/m2/hour and was significantly lower than the norm, which is up to 6.0 mg/m2-year. The magnitude of the destructive action of 20, 25, 30, 35% of the concentration of orthophosphoric acid in an acid mist and disinfectant on the plates of aluminum was higher than the norm, respectively, at 2.42, 2.88, 3.09 and 3.60 times, and the rate of destruction – respectively, at 2.17, 2.63, 2.82 and 3.28 times. Therefore, the addition of a nitric acid ammonium inhibitor in the experimental variants of acidic detergent disinfectant resulted in a decrease in the magnitude of the destruction of aluminum. The results were higher than the norm but were significantly lower (P ≤ 0.05) compared to control, which used «Ecocid», an acid concentration of 30%.

Density multiplication of pores and their propagation in a thin layer of nanoporous alumina on silicon substrates

In this work, perfectly organized triangular arrays of vertical nanopores are formed in an alumina matrix by combining a pre-patterning technique with the natural ability of alumina to form a triangular unit cell. More precisely, we imprinted a triangular array of indents on a thin layer of aluminum deposited on silicon substrates using nano-imprint lithography. During the anodization process, we forced the growth of pores in and in-between the indents obtaining a larger number of pores in the final alumina array than the initial number of indents patterned on the aluminum. Adapting the anodization conditions, a density multiplication by three was successfully achieved with a very good surface organization. The experimental details of the process are described in this paper. We studied in details the inner organization of the pores and we identified differences in their propagation between oxalic and orthophosphoric acid. The former showed a good surface propagation until 1500nm in depth. On the contrary, the latter showed a perturbation in the organization at 450nm: at this depth, the induced pores stopped whereas the indented ones rearranged into two or three. A longer shift in the initiation of the induced pores seemed to causes this poor propagation. A systematic study was performed to investigate the effect of the anodization conditions on the pores’ propagation. We demonstrate that the optimization of the orthophosphoric acid concentration and the applied voltage towards harder anodization conditions, i.e. to higher values, allows a better control of this self-assembling process and deeper order propagation until more than 1000nm.

Development and validation of simple RP-HPLC-PDA analytical protocol for zileuton assisted with Design of Experiments for robustness determination

A simple, rapid, sensitive, robust, stability-indicating RP-HPLC-PDA analytical protocol was developed and validated for the analysis of zileuton racemate in bulk and in tablet formulation. Development of method and resolution of degradation products from forced; hydrolytic (acidic, basic, neutral), oxidative, photolytic (acidic, basic, neutral, solid state) and thermal (dry heat) degradation was achieved on a LC – GC Qualisil BDS C18 column (250mm×4.6mm×5μm) by isocratic mode at ambient temperature, employing a mobile phase methanol and (0.2%, v/v) orthophosphoric acid in ratio of (80:20, v/v) at a flow rate of 1.0mLmin−1 and detection at 260nm. ‘Design of Experiments’ (DOE) employing ‘Central Composite Design’ (CCD) and ‘Response Surface Methodology’ (RSM) were applied as an advancement to traditional ‘One Variable at Time’ (OVAT) approach to evaluate the effects of variations in selected factors (methanol content, flow rate, concentration of orthophosphoric acid) as graphical interpretation for robustness and statistical interpretation was achieved with Multiple Linear Regression (MLR) and ANOVA. The method succeeded over the validation parameters: linearity, precision, accuracy, limit of detection and limit of quantitation, and robustness. The method was applied effectively for analysis of in-house zileuton tablets.

Magnetic and structural properties of iron phosphate–phenolic soft magnetic composites

This work focuses on the effect of phosphate modification on the magnetic and surface properties of iron–phenolic soft magnetic composite materials. Fourier transform infrared (FTIR) spectra, EDX analysis, distribution maps, X-ray diffraction pattern and density measurements show that the particles surface layer contains a thin layer of nanocrystalline/amorphous phosphate with high coverage of powders surface. Magnetic measurements show that phosphating treatment decreases the loss factor, imaginary part of permeability, increases the electrical resistivity and operating frequencies by decreasing the effective particle size. The operating frequency increases from 200 kHz for uncoated-powders samples to 1 MHz for phosphated-powders samples at optimum concentration. Phosphated iron powders that are covered by 0.7 wt% of phenolic resin exhibits lower magnetic loss and higher frequency stability. The minimum loss factor and maximum permeability at each frequency can be obtained for 0.01 g/ml orthophosphoric acid concentration in comparison with other concentrations including 0.005 and 0.04 g/ml.

Esterification of viscose fibres with orthophosphoric acid and study of their physicochemical and mechanical properties

Esterification of viscose fibres with aqueous solutions of orthophosphoric acid and urea at different ratios of components was investigated. It was shown that in phosphorylation of cellulose with these solutions, one-substituted cellulose phosphates are formed and a side process of formation of cellulose carbamates takes place together with accumulation of phosphate groups. A decrease was found in the mechanical strength of the phosphorylated cellulose preparations and the degree was a function of the concentration of orthophosphoric acid and urea as the phosphorylating solution. Phosphorus-containing viscose fibres (up to 0.5 mmole/g of phosphate groups) obtained in solutions of orthophosphoric acid and urea with a 0.25–0.63 and 3.33–4.17 M concentration have the most satisfactory mechanical properties and stability in phosphate buffer with pH 7.5.

Soluble manganese(IV) as a chemiluminescence reagent for the determination of opiate alkaloids, indoles and analytes of forensic interest

We present the results of our investigations into the use of soluble manganese(IV) as a chemiluminescence reagent, which include a significantly faster method of preparation and a study on the effect of formaldehyde and orthophosphoric acid concentration on signal intensity. Chemiluminescence detection was applied to the determination of 16 analytes, including opiate alkaloids, indoles and analytes of forensic interest, using flow injection analysis methodology. The soluble manganese(IV) reagent was less selective than either acidic potassium permanganate or tris(2,2′-bipyridyl)ruthenium(III) and therefore provided a more universal chemiluminescence detection system for HPLC. A broad spectral distribution with a maximum at 730 ± 5 nm was observed for the reaction between the soluble manganese(IV) and a range of analytes, as well as the background emission from the reaction with the formaldehyde enhancer. This spectral distribution matches that reported for chemiluminescence reactions with acidic potassium permanganate, where a manganese(II) emitting species was elucidated. This provides further evidence that the emission evoked in reactions with soluble manganese(IV) also emanates from a manganese(II) species, and not bimolecular singlet oxygen as suggested by previous authors.

Thermal and electrical properties of Tri Glycine Sulpho Phosphate (TGSP) and L-Asparagine doped TGSP crystals

Tri Glycinsulphate with partial substitution of phosphoric acid, namely Tri Glycine Sulpho Phosphate (TGSP) has been grown by slow cooling method. Habit modifications have been observed with change in the concentration of ortho phosphoric acid (H3PO4). Monoclinic structure of the grown crystals has been confirmed using X-ray diffraction analysis. TGSP crystals doped with L – Asparagine were also grown. The doping effect is qualitatively estimated using FTIR analysis. TGA, DTA studies and dielectric measurements were carried out for pure and L-Asparagine doped TGSP crystals to investigate the thermal and electrical properties of the crystals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Improvement of white pinewood properties by impregnation with thiourea-formaldehyde resin and orthophosphoric acid

White pinewood was impregnated with thiourea–formaldehyde (TUF) resin and orthophosphoric acid (OPA) as a crosslinking agent. The best weight gains (55–138%) were obtained after impregnation with an aqueous solution of TUF resin for 1 h and impregnation with aqueous solutions of OPA at different concentrations for 1 h. Water uptake of treated wood was found to be 23% after a water-soaking test of 168 h, and a maximum antiswell efficiency was found to be 18% for a 85% OPA solution. Compression strength of the treated wood also improved with the highest value 62 KN/m2 for wood treated with a 70% OPA solution versus a value of 40 KN/m2 for untreated samples. Fire retardancy of the treated wood samples was also improved based on concentration of OPA. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 390–397, 2000

Morphology of gallium orthophosphate crystals grown under hydrothermal conditions

Gallium orthophosphate crystals with sizes of 5 mm and more have been obtained by spontaneous nucleation from hydrothermal 5.6 – 15 M orthophosphoric acid solutions. Preferable concentrations of solvent were found in the range of 11 – 12 M, the temperature difference should not be over 6–10°C at the heating rate of 4 – 5 °C/day. Morphological investigations are carried out using optical and polarizing microscopies. GaPO 4 crystals, like quartz and berlinite, tends to grow with well developed { 1 0 1 }, { 0 1 1 }, { 1 0 0 }, { 1 0 2 }, and { 0 1 2 } faces, and they were divided into three habit types. Effect of orthophosphoric acid concentration on the crystal habit has been studied.

ファインセラミックスのフォトエッチング 高温りん酸によるエッチング

The compositions of hot phosphoric acid between 200 and 320°C under refluxing and nonrefluxing (open) conditions were studied by means of the paper chromatography and the colorimetric analysis. The etch rates of various ceramics were measured in the acid under several conditions. The composition of the nonrefluxed open acid varied with time due to dehydration and condensation. On the other hand, refluxing water vapor during heating provided a good etching condition in which the temperature and composition of the acid were maintained constant. Under refluxing condition, two types of phosphoric acid were available ; a boiling acid and an equi-composition acid. In the refluxed acids, the etch rates of ceramics were increased with temperature. Alumina ceramic had an etch rate of several μm/min at temperatures above 250°C in the refluxed boiling acid. The etch rates for the equi-composition acid was lower than those for the boiling acid at the same temperature, due to a higher degree of condensation for the equi-composition acid. The etch rate of alumina ceramic was also increased with the concentration of orthophosphoric acid.

More SensitiveFlamelessAtomicAbsorptionAnalysisof Vanadiumin Tissueand Serum

Abstract Vol. 28 p 79: See response in Letter of Cornelisand Versieck, p 1709. p 91: In the note added in proof, "131" should read "1.31." p 241: In Table 1, "6.5" should read "65"; in the footnote to Table 2, "0.05" should read "0.5" and the next to last paragraph should read: "Finally, in a few instances we have compared the glucose values obtained by using a drop of sample according to the instructions, versus dipping the strips into the sample, and found some variance between the values obtained by the two methods." p 344: Under "staining reagent," the correct concentration of orthophosphoric acid is 160 g/L (not 80 g/L). It is prepared by diluting 95 mL of the concentrated acid (850 g/kg, relative density 1.69 g/mL) to 1 L with distilled water. p 418: ref. 94, cited in the first full paragraph, should read "84." p 419: The volume number of ref. 1 should be 50, not 19. p 502: Corrections to two equations: the term (S2y - S2x) should read (S2y - S2x)2 and in the third equation in the second column delete the repetition of the term "(wx4)," which should only appear once. p 531: In last full paragraph in column one, the word "propionate" in the next to last line should instead read "dimethyl sulfoxide." p 614: References 21 and 22 are missing 21: Gerhardt, W., Ljungdahl, L., Borjesson, J., et al., Creatine kinase B-subunit activity in human serum. I. Development of an iminunoinhibition method for routine determination of S-creatine kinase B-subunit activity. Clin. Chim. Acta78, 29-41 (1977). 22: Neumeier, D., Prellwitz, W., Wurzburg, U., et al., Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity: Activity kinetics and diagnostic significance in myocardial infarction. Clin. Chim. Acta73, 445-451 (1976). p 727: With regard to this Letter, the authors later pointed out that although the first sentence states that glycosylated hemoglobins have a higher isoelectric point, glycosylation actually decreases the isoelectric point. Later (p 728) they speculated that the fast hemoglobin variant might be HbN-Baltimore (α2β295Lys→Glu), but two reference laboratories identified it as the slightly slower HbJ-Baltimore (α2β216Gly→Asp). p 735: In the middle column, the third full paragraph, "Department of Internal Medicine" should read "Department of Laboratory Medicine." p 736: In column one, under Awards, the citation should have stated "in recognition of his contribution in the, field of clinical chemistry." p 1199: Table 1 folate concentrations should be "mg/L," not rg/L.

Kinetics of the Phosphatizing reaction of carbonyl iron powders

1. Phosphate film formation on the surfaces of carbonyl iron powder particles occurs through a heterogeneous first-order reaction which slows down with time as the film thickness grows. 2. The mean rate of the phosphate film formation reaction depends on the concentration of orthophosphoric acid in acetone, the concentration of carbonyl iron powder in the liquid phase, and the temperature. 3. The mean rate of the reaction attains its maximum value at an acid concentration in acetone of 0.01 g/ml (1.28 wt.%) and a CI powder concentration in the liquid phase of 2.5 g/ml. 4. The degree of reactive transformation ranges from 24.8 to 32.1%, the reaction coming to an end after 9.2-9.6 sec. 5. The kinetics of the CI powder phosphatizing reaction is not the limiting stage of the process, which can therefore be optimized by introducing improvements in the other stages. 6. One of the principal processing parameters in the phosphatizing of CI powders is the concentration of orthophosphoric acid in acetone. Control over this parameter can be conveniently exercised by measuring the solution pH.

Study of corundum phosphate-bonded concrete

The concentration of orthophosphoric acid affects the properties of corundum concretes: with an increase in the concentration of the acid in the concretes during drying a larger quantity of AlPO4 is formed.

Inorganic Extraction Studies on the System between Bis(2-ethyl hexyl)-orthophosphoric Acid and Hydrochloric Acid. II

The influence of solvent concentration in extractions from hydrochloric acid solutions of about flfty elements is shown. The distribution ratio, K/sub d,/ of a given nuclide was radiometrically determined. The details of and some remarks on the method used are given. The bis(2-ethyl hexyl)-orthophosphoric acid concentration in the organic layer was varied in the range 0.5 to 50 volume% for most extractions. Extraction with barren toluene containing no HDEHP was also checked. The acidity in the aqueous layer was kept constant in a series of extractions of a given element. (N.W.R.)