Potassium Phosphate Research Articles

Investigation into “hair” inclusions in large-sized KDP crystals grown by traditional method

Potassium dihydrogen phosphate (KDP) crystals are widely used in high-energy laser facilities for harmonic generation. An important defect observed in KDP crystals, known as "hair" inclusions in large-size crystals grown by traditional methods, was investigated using ultra-microscopy. Most of the "hair" inclusions within the crystals have a straight chain structure, while only a few displays a curved formation. The "hair" inclusions consist of multiple liquid inclusions and exhibit a chain-like structure with quasi-periodic features. The size of these liquid inclusions varies, ranging from 17.54 to 56.90 μm, and show a chain density between 0.90 mm−1 and 20.77 mm−1. The angles of the "hair" inclusion orientations about the c-axis range from 30° to 79°, corresponding to the dislocations in KDP crystals. Furthermore, the study examined the impact of "hair" inclusions on the transmittance of the crystals. This investigation aims to enhance the understanding of “hair” inclusions in traditionally grown KDP crystals and attempts to clarify the factors leading to the formation of these inclusions. It also offers a theoretical and experimental basis for reducing these inclusions in KDP crystals.

Effect of Three Foliar Inhibitors on Accumulation of Cd and As in Rice Grains

This study investigated the impact of single and combined applications of three foliar inhibitors on the accumulation of cadmium （Cd） and arsenic （As） in rice grains. Two rice varieties, Songyazao 1 （for early rice） and Wuxiang Youyue （for late rice）, were selected for this experiment. We established nine treatments using a pot experiment method, including a control （CK） treated with no foliar inhibitor and three individual foliar inhibitors： cysteine （L-Cys）, potassium sulfide （K2S）, and dipotassium hydrogen phosphate （K2HPO4）. We then combined the applications of two foliar inhibitors： L-Cys with low/high concentrations of K2S, L-Cys with low/high concentrations of K2HPO4, and K2S with a low concentration of K2HPO4. The results showed that the single and combined applications of foliar inhibitors reduced Cd and As concentrations in rice grains. The Cd content in brown rice treated with L-Cys and K2S/K2HPO4 was reduced below the standard limit for food safety of 0.20 mg·kg-1. Compared to the CK, the content of inorganic arsenic （IAs） in early and late rice decreased by 4.68%-56.75% and 2.84%-16.91%, respectively. Foliar inhibitors applied individually or in combinations facilitated the transport of Cd and As from the stem to the leaf while inhibiting their transport from the leaf to the rice grain. This resulted in the sequestration of Cd and As within the leaf cell wall, ultimately reducing the content of these elements in rice grains. Among the combination treatments, the application of L-Cys and high-concentration K2S achieved the best results. The Cd content in early and late rice decreased by 37.64% and 26.37%, respectively, falling below 0.20 mg·kg-1. The IAs content in early and late rice was reduced to 0.10 mg·kg-1 （below 0.20 mg·kg-1） and 0.24 mg·kg-1, respectively. This study provides a valuable theoretical foundation and empirical data to support the achievement of safe rice production practices.

Unapproved potassium phosphates drug product: risk of aluminium toxicity in infants

Unapproved potassium phosphates drug product: risk of aluminium toxicity in infants

Effect of seed priming using potassium dihydrogen phosphate on seedlings emergence, growth and yield of Bambara groundnut (<i>Vigna subterranea</i> (L) Verdc.)

Effect of seed priming using potassium dihydrogen phosphate on seedlings emergence, growth and yield of Bambara groundnut (<i>Vigna subterranea</i> (L) Verdc.)

Efficacy of Potassium Iodide and Glutathione for Correlation of Dentin Discoloration Caused by Silver Diamine Fluoride.

This study aimed to investigate and contrast the degree of dentin discoloration resulting from the application of silver diamine fluoride (SDF) alone, SDF in combination with potassium iodide (KI), and SDF in combination with glutathione. The aim was to assess the effectiveness of these combinations in reducing the aesthetic issues associated with SDF treatment in minimally invasive dentistry and preventive procedures. We conducted this in-vitro study on 136 permanent molar teeth. The teeth were randomly assigned to two main groups of total-etch and self-etch and four subgroups of control, SDF, SDF plus KI, and SDF with glutathione. The teeth underwent colorimetry before and 1 week after applying materials to compare the color change. We mounted the teeth in acrylic resin 1 mm below their cementoenamel junction. A low-speed diamond saw and 600-grit silicon carbide abrasive paper eliminated the occlusal enamel for 10 seconds under water coolant, exposing the dentin. The teeth were then immersed in a demineralizing solution (pH of 4.4, 50 mmol acetate, 2.2 mmol potassium dihydrogen phosphate, and 2.2 mmol calcium chloride) for 7 days at 37°C to induce dentin demineralization and simulate demineralized dentin artificially. The teeth were then gently polished with 600-grit silicon carbide abrasive paper to create a standard smear layer and eliminate the demineralized dentin layer. 136 teeth were evaluated in the total-etch (n = 68) and self-etch (n = 68) groups. Glutathione and KI significantly decreased the discoloration caused by SDF (P<0.05). No significant difference was noted in color change between SDF/glutathione and SDF plus KI groups (P > 0.05). In self-etch groups, glutathione yielded an ∆E=4.12, while KI yielded an ∆E=4.44, with no significant difference. The application of glutathione and KI can significantly decrease dentin discoloration caused by SDF.

The use of an RP-HPLC-UV method for the analysis of oxcarbazepine in the presence of its preservatives; stability studies and application to human plasma samples

AbstractA simple, sensitive, selective, accurate and precise method was developed and fully validated for determination of oxcarbazepine (OXC) in presence of their preservatives and determination of oxcarbazepine (OXC) in human plasma. A reversed phase liquid chromatography (RP-HPLC) with UV detection techniques were applied for separation and quantification of studied drug OXC. Successful separation of the drug from methyl paraben (M.P.), propyl paraben (P.P.) and potassium sorbate (P.ST.) was achieved on a Kromasil C18 column (5 μm particle size, pore size 300 Å, l × I.D. 250 × 4.6 mm). The mobile phase that contain aqueous 0.05M potassium dihydrogen phosphate buffer (pH 7): acetonitrile, (50: 50, %v/v). The method was linear over concentration ranges 5.0–50 μg mL−1 for OXC. Bioanalytical validation of the developed method was carried out according to US-FDA guidelines and revealed a good linear relations over a range of (5.0–50), (0.5–10), (0.05–0.15), and (1.0–10) μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, with a correlation coefficient (R2) of more than 0.999. Limit of detection (LOD) were 1.15, 0.03, 0.01 and 0.04 μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, Intra and inter-day precisions, calculated as percentage relative standard deviation (% RSD), were lower than 2.0%. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies through the analysis of plasma samples taken from blood bank.

Зависимость кормовой ценности эспарцета песчаного от листовых подкормок

In the feed production system of the Lower Volga region, more than 60% of forage crops are located on irrigated lands. Only these lands can be considered a guaranteed source of sustainable food supply. More than 80% of the feed from their gross production is harvested from irrigated lands, therefore, studies on the dependence of the feed value of sandy esparcet on leaf fertilizing are certainly relevant. The aim of the research was to increase the efficiency of esparcet cultivation in the conditions of the Lower Volga region by improving the use of mineral fertilizers. Experiments to study the dependence of the feed value of esparcet in the form of green mass on leaf fertilizing with water-soluble mineral fertilizers were conducted from 2017 to 2023 on irrigation in the zone of light chestnut soils in the Prigorodnoye SEC of the Svetloyarsky district of the Volgograd region. Mineral fertilizers were applied in the form of leaf fertilizing during the period of active growth of the esparcet according to the following schemes: 1. Control (without leaf dressing); 2. Monophosphate at the rate of 0.5 kg/ha per top dressing; 3. Monophosphate with adhesive at the rate of 0.5 kg/ha per top dressing. As a result of the experiments conducted, it was found that in the variant using potassium monophosphate, the yield of the green mass of the Rusich variety was 8.2 t/ha, or 18.8% more, and in the variant using potassium monophosphate with an adhesive by 11.7 t/ha, or 26.8% more compared to the control variant. The largest accumulation of feed units of 12.8 t/ha was found in the Rusich variety on the variant of leaf fertilizing with potassium monophosphate with an adhesive, which turned out to be 0.6 t/ha more than in the experiment from 2017 to 2019. The highest content of digestible protein of 2.21 t/ha was found in the Rusich variety on a variant of leaf fertilizing with potassium monophosphate with an adhesive. The largest amount of metabolic energy of 101.7 GJ was contained in the Rusich variety on a variant of leaf fertilizing with potassium monophosphate with an adhesive. The lowest amount of metabolic energy was contained in the Sandy 22 variety in the control variant without leaf fertilizing and averaged 70.3 GJ for 2021-2023.

Rhamnolipids Enhance Bioremediation of Petroleum-Contaminated Soil

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215952, “Enhancing Bioremediation of Petroleum-Contaminated Soil Using Rhamnolipids: A Combined Laboratory and Field Study,” by Pan Ni, Lehigh University; Yonglin Ren, SPE, Stepan Oilfield Solutions; and Derick G. Brown, Lehigh University, et al. The paper has not been peer reviewed. _ Hydrocarbon spills can occur at various stages of the oil and gas exploration and production process. Treating these spills onsite to avoid more-expensive excavation and incineration processes would be beneficial. The study outlined in the complete paper aims to optimize the use of rhamnolipid biosurfactants for enhancing the bioremediation of hydrocarbon-contaminated soil. The goal of this work was to explore the effects of rhamnolipid application on hydrocarbon degradation rate under both laboratory and field conditions and to examine the effects of this treatment on the indigenous soil microorganism population. Introduction The authors write that, to the best of their knowledge, previous research studies on rhamnolipid-based soil remediation focused on either laboratory or field tests and that comparison between laboratory-scale and field-scale tests is overlooked but necessary for practical applications. Materials and Methods Materials and Chemicals. The soil used for this work (23 kg for the laboratory test, 10 metric tons for the field test) was obtained from a contaminated site in Longford Mills, Canada. The soil properties are presented in Table 1 of the complete paper. The rhamnolipid stock solution featured 9.8 wt% rhamnolipid blends in deionized water. Another commercial remediation agent (enzyme-based) was used in the field test to compare with the performance of rhamnolipid. Ammonium chloride (NH4Cl) and potassium hydrogen phosphate (K2HPO4) also were used along with sodium hydroxide (NaOH). Experimental Setup. Both laboratory and field tests were ex-situ tests using simulated soil piles. The laboratory test was conducted for 193 days. For the laboratory experiments, an aerobic/anaerobic respirometer system equipped with a low-temperature incubator was used to monitor the in-situ oxygen uptake inside eight reactors (Fig. 1). Each reactor contained 250 g of soil with rhamnolipid doses of 0, 0.1, 0.5, and 1 g/kg. The temperature was set to 25°C. Inside each reactor was placed 10 mL of 4-M NaOH in a 20-mL glass beaker to adsorb the produced CO2. A parallel set of eight reactors was prepared and operated under the same conditions. The nutrients of nitrogen and phosphorous (NH4Cl and K2HPO4) were added at specific times based on the oxygen uptake rate monitored by the respirometer. To avoid the possible inhibition of the microbes in the soil as a result of high ionic strength (greater than 160 mM) in the soil pore water, NH4Cl and K2HPO4 were added so that the molar concentration in the soil pore water did not exceed 100 mM. The field test is being conducted in Longford Mills, Ontario, Canada, and is ongoing at the time of writing. For the field test, 10 metric tons of soil were mixed to achieve homogeneity before the preparation of the soil piles. Five different treatment conditions were examined using duplicate soil piles (10 piles total), with each consisting of 1 metric ton of soil. Nutrient addition was similar to that used in the laboratory tests. Temperature and moisture were monitored every few days at five points in each soil pile, and the pH was monitored once every month at five points.

Role of defense inducers in modulating biochemical responses to Alternaria leaf blight

Alternaria leaf blight of sunflower has been considered as a potentially destructive disease. Due to cons of using chemical pesticides, the present investigation was undertaken to know the effect of three plant defence inducers viz., salicylic acid, monopotassium phosphate and sodium propionate for the eco-friendly management of Alternaria leaf blight disease. Seed treatment with salicylic acid at 100 ppm followed by foliar spray of salicylic acid at 100 ppm recorded highest secondary metabolites such as flavonoids (68.71 mg g FW) and phenols (73.53 mg g FW) -1 -1 -1 when compared to phenolics (45.07 mg g FW) and flavonoids (51.43 mg g FW) in control plants -1 . Seed treatment with salicylic acid at 100 ppm followed by foliar spray of salicylic acid at 100 ppm showed increased defense enzymes such as superoxide dismutase (40.45 mg/50 per cent inhibition) and peroxidase (16.86 mg min mg protein) when compared to superoxide dismutase -1 -1 (54.36 mg/50 per cent inhibition) and peroxidase (9.63 mg min mg protein) in control plants. This study -1 -1 demonstrated that seed treatment followed by foliar spray with salicylic acid can be used effectively for the management of Alternaria blight in fields as it exhibited more defense enzyme activity and secondary metabolites.. KEYWORDS :Alternaria, defense enzymes, secondary metabolites, seed treatment

Determination of solid-state acidity of lyophilized trehalose containing citrate, phosphate, and histidine buffers using UV/VIS diffuse reflectance and solid-state NMR spectroscopy

Changes in the protonation state of lyophilized proteins can impact structural integrity, chemical stability, and propensity to aggregate upon reconstitution. When a buffer is chosen, the freezing/drying process may result in dramatic changes in the protonation state of the protein due to ionization shift of the buffer. In order to determine whether protonation shifts are occurring, ionizable probes can be added to the formulation. Optical probes (dyes) have shown dramatic ionization changes in lyophilized products, but it is unclear whether the pH indicator is uniform throughout the matrix and whether the change in the pH indicator actually mirrors drug ionization changes. In solid-state NMR (SSNMR) spectroscopy, the chemical shift of the carbonyl carbon in carboxylic acids is very sensitive to the ionization state of the acid. Therefore, SSNMR can be used to measure ionization changes in a lyophilized matrix by employing a small quantity of an isotopically-labeled carboxylic acid species in the formulation. This paper compares the apparent pH of six trehalose-containing lyophilized buffer systems using SSNMR and UV-Vis diffuse reflectance spectroscopy (UVDRS). Both SSNMR and UVDRS results using two different ionization probes (butyric acid and bromocresol purple, respectively) showed little change in apparent acidity compared to the pre-lyophilized solution in a sodium citrate buffer, but a greater change was observed in potassium phosphate, sodium phosphate, and histidine buffers. While the trends between the two methods were similar, there were differences in the numerical values of equivalent pH (pHeq) observed between the two methods. The potential causes contributing to the differences are discussed.

Листовые подкормки при возделывании козлятника восточного на орошении

To strengthen the fodder base of animal husbandry in the Lower Volga region, first of all, it is necessary to expand the range of fodder crops and varieties, to optimize their nutritional regime, to create optimal conditions for their cultivation, in other words, to ensure the production of a large amount of valuable fodder in a relatively limited area, in this regard, the improvement of cultivation technology of eastern goatgrass is relevant. The purpose of the research was to increase the efficiency of cultivation of oriental goatgrass in the Lower Volga region through the use of mineral fertilizers and growth stimulants. Experiments to study the dependence of productivity of oriental goatgrass in the form of green mass on leaf fertilization with water-soluble mineral fertilizers were conducted from 2016 to 2023 on an irrigated plot with irrigation regime of 70...85...70 % NV by sprinkler machine “Valey”. In the experiment in 2017, varieties of oriental goatgrass Krivich, Yubilyar, Kazbek were sown. The general background before sowing was applied mineral fertilizers in the form of azofosk at a dose of N24P24K24. In each cutting in the phase of active growth of plants were fertilized with potassium monophosphate with and without a sticking agent at the rate of 0.5 kg/ha for one fertilizer. On average for seven years, the largest leaf area - 43.7 thousand m2/ha and photosynthetic potential - 7.87 million m2 x dn./ha of oriental goatgrass in the experiment were in the variety Jubilar in the variant of potassium monophosphate with a sticking agent. On average for seven years, the largest leaf area - 43.7 thousand m2/ha and photosynthetic potential - 7.87 million m2 x dn/ha of oriental goatgrass in the experiment were in the variety Jubilar in the variant of potassium monophosphate with a sticking agent. Also on this variant the maximum yield of green mass - 92.7 t/ha, dry matter content - 23.2 t/ha, fodder units - 20.4 t/ha and exchangeable energy - 1.62 GJ/ha were observed.

Influence of citric acid on optical properties of unidirectional grown potassium dihydrogen phosphate crystals

Influence of citric acid on optical properties of unidirectional grown potassium dihydrogen phosphate crystals

Damage effects of KDP crystals induced by nanosecond laser

Abstract The surface morphology, compositions, microstructures, and chemical bond vibrations of potassium dihydrogen phosphate (KDP) crystals induced by nanosecond laser with different wavelengths, at different energy density are studied by scanning electron microscopy (SEM) and infrared spectroscopy (IR) techniques. SEM results showed that with the increase of laser energy density, the damage region on KDP surfaces presented three parts evidently. And the damage area increases nonlinearly with the laser energy density, accompanied by an increase in O element contents and a decrease in P and K element contents. Meanwhile, at the same energy density, the damage area induced by the 355 nm nanosecond laser is much larger than that by the 1064 nm nanosecond laser. Infrared spectrum results revealed that the laser irradiation leads to a break in hydrogen bonds and a dehydration of KDP crystals, in conjunction with a generation of P=O and P-H bonds. Moreover, with the increase of the laser energy density, the KDP crystal is damaged firstly, and then is annealed and repaired, finally is destroyed again. In addition, after irradiation at 10 J/cm2, all vibration modes of KDP crystals weaken or even disappear, and the sever damage occurs.

Preharvest applications of monopotassium phosphate to improve fruit quality and volatilome composition in cold-stored cherry tomatoes

The experiment addressed the effects of preharvest KH2PO4 foliar spraying (20 mmol · L−1) on fruit quality and composition (including volatile organic compounds, VOCs) of cherry tomatoes (‘Caravaggio’, ‘Sugarland’ and ‘Top Stellina’) after 0 (S0), 7 (S7) and 14 days (S14) of storage at 8.0 °C. On the average of the 3 genotypes, the KH2PO4 treatment improved fruit pressure firmness, total soluble solids (TSS), titratable acidity (TA), total phenols and carotenoids concentrations, along with the fruits' antioxidant capacity (by up to 17% for FRAP assay). Within the S7–S14 period, control fruits showed the highest reductions in TSS, TSS/TA ratio and total carotenoids (−17, −12 and −45, respectively), whereas treated fruits proved the strongest increase in DPPH (+12%). Sixteen out of 32 VOCs were promoted following KH2PO4 application, including the aldehydes hexanal, (E)-2-hexenal and (Z)-3-hexenal and the apocarotenoids (E)-citral, (E)-β-ionone, geranylacetone and 6-methyl-5-hepten-2-one. Proceeding from S0 to S14, several VOCs decreased more strongly in control fruits, as for hexanal (−48%∖) and total aldehydes (−42%∖, whereas at S14 treated fruits had higher concentrations of linalool, geranylacetone and 6-methyl-5-hepten-2-one (1.06, 52.50 and 79.27 μg · kg−1, respectively). ‘Caravaggio’ demonstrated the strongest apocarotenoid reduction at S14, whereas ‘Top Stellina’ was more responsive to KH2PO4 (mainly for β-cyclocitral, geranylacetone and total terpenes/terpenoids), thus highlighting the central role of the genotype in responding to other experimental factors. Nonetheless, these results suggest that proper preharvest KH2PO4 applications can preserve specific commercial, nutritional and quality traits of cold-stored cherry tomatoes.

Determination of anamorelin concentration in human plasma using a simple high-performance liquid chromatography-ultraviolet detection method.

Anamorelin, a non-peptide ghrelin analog and growth hormone secretagogue, is a novel oral drug used to treat cancer cachexia. Patients with cancer cachexia frequently use several drugs and anamorelin is a substrate of cytochrome P450 (CYP) 3A4; therefore, drug-drug interactions with CYP3A4 inhibitors and inducers pose a clinical problem. In this study, we aimed to determine the concentration of anamorelin in human plasma using a simple high-performance liquid chromatography-ultraviolet (HPLC-UV)-based method. The analysis involved extracting a 200-μL plasma sample and protein precipitation using solid-phase extraction. Anamorelin was isocratically separated using a mobile phase consisting of 0.5% potassium dihydrogen phosphate (pH 4.5) and acetonitrile (61:39, v/v) on a Capcell Pack C18 MG II column (250 mm × 4.6 mm) at a flow rate of 1.0 mL/min and monitored at a detection wavelength of 220 nm. The calibration curve was linear within a plasma concentration range of 12.5-1,500 ng/mL, with a coefficient of determination of 0.9999. The intra- and inter-day coefficients of variation were 0.37-6.71% and 2.05-4.77%, respectively. The accuracy of the assay and recovery were 85.25-112.94% and > 86.58%, respectively. This proposed HPLC-UV method is simple and can be applied in clinical settings.

Injectable bone cement based on magnesium potassium phosphate and cross-linked alginate hydrogel designed for minimally invasive orthopedic procedures

Bone cement based on magnesium phosphate has extremely favorable properties for its application as a bioactive bone substitute. However, further improvement is still expected due to difficult injectability and high brittleness. This paper reported the preparation of novel biocomposite cement, classified as dual-setting, obtained through ceramic hydration reaction and polymer cross-linking. Cement was composed of magnesium potassium phosphate and sodium alginate cross-linked with calcium carbonate and gluconolactone. The properties of the obtained composite material and the influence of sodium alginate modification on cement reaction were investigated. Our results indicated that proposed cements have several advantages compared to ceramic cement, like shortened curing time, diverse microstructure, increased wettability and biodegradability and improved paste cohesion and injectability. The magnesium phosphate cement with 1.50% sodium alginate obtained using a powder-to-liquid ratio of 2.5 g/mL and cross-linking ratio 90/120 of GDL/CC showed the most favorable properties, with no adverse effect on mechanical strength and osteoblasts cytocompatibility. Overall, our research suggested that this novel cement might have promising medical application prospects, especially in minimally invasive procedures.

A novel QbD HPLC approach for the concurrent analysis of amoxicillin, amprolium, and ethopabate in food samples and dosage forms

A simple, rapid, and sensitive reversed-phase HPLC method coupled with photodiode array detection (PDA) was developed for the simultaneous estimation of three co-administered antibacterial drugs, amprolium, ethopabate, and amoxicillin for the first time. An analytical quality-by-design (QbD) approach was adopted to optimize the developed approach. A two-level full factorial design (25 FFD) was implemented to optimize how variable factors affected chromatographic responses. On a Hypersil BDS C18 column, the chromatographic separation was carried out using isocratic elution at 40.1 °C. The mobile phase consisted of methanol: potassium phosphate buffer containing 5.76 mM heptane sulphonate (9.05 mM; pH 3.32, 44.8:55.2 % v/v) pumped at a flow rate of 0.8 mL/min and an injection volume of 20.0 μL. In less than 7 min, the suggested method was able to separate the ternary mixture with a challenging ratio of 1: 15.6: 1 for amoxicillin, amprolium, and ethopabate, respectively. The calibration curves showed excellent linearity over the concentration ranges of 0.50–30.0, 0.30–30.0, and 0.05–20.0 μg/mL, respectively. Recovery percentages ranged from 90.30 % to 111.13 % with %RSD less than 2 % were obtained upon spiking to chicken tissues, liver, and egg samples, indicating the suitability of the proposed method for determining of the studied drugs in complicated food matrices. Furthermore, the proposed method was successfully applied to determine the studied drugs in their commercial formulations. Full validation was carried out according to ICHQ2 (R1) guidelines. Finally, the method's greenness and ecofriendliness were evaluated using various metrics tools, including the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE).

NEW APPROACH FOR ASSURING HIGHER QUALITY OF CALCIUM OROTATE BY ESTIMATING OROTIC ACID CONTENT USING STABILITY INDICATING RP-HPLC METHOD

Calcium orotate is one of the highly prescribed calcium salts. The orotic acid content is crucial for exhibiting its high bioavailability. There are no methods available to estimate orotic acid content in calcium orotate. The primary objective of this study was to develop and validate a robust method for the estimation of orotic acid from the bulk calcium orotate. A stability indicating RP-HPLC method was developed using an isocratic condition of mobile phase comprising 20 mM of monobasic potassium phosphate in water (pH 2.5) with phosphoric acid at a flow rate of 1 mL min-1 over C-18 (ODS, 250 × 4.6 mm) column at ambient temperature with UV detection at 214 nm. It was validated with respect to accuracy, specificity, precision, linearity, range, robustness and system suitability. Real sample analysis was also performed to test the applicability for regular analysis of calcium orotate bulk samples to assure its quality.

Durability of Magnesium Potassium Phosphate Cements (MKPCs) under Chemical Attack.

Magnesium phosphate cements (MPCs), also known as chemically bonded ceramics, represent a class of inorganic cements that have garnered considerable interest in recent years for their exceptional properties and diverse applications in the construction and engineering sectors. However, the development of these cements is relatively recent (they emerged at the beginning of the 20th century), so there are still certain aspects relating to their durability that need to be evaluated. The present work analyses the chemical durability of magnesium potassium phosphate cements (MKPCs) during 1 year of immersion in three leaching media: seawater, a Na2SO4 solution (4% by mass) and deionized water. For this, pastes of prismatic specimens of MKPC, prepared with different M/P ratio (2 and 3), were submitted to the different chemical attacks. At different ages, the changes on the mechanical strengths, microstructure (BSEM, MIP) and mineralogy (XRD, FTIR, TG/DTG) were evaluated. The results obtained indicate that, in general terms, MKPC systems show good behavior in the three media, with the more resistant system being the one prepared with a M/P molar ratio of 3.

Rheology and buildability of sustainable 3D printed magnesium potassium phosphate cement composites incorporating MgO-SiO2-K2HPO4

MKPCs with unique advantage of superior strength, excellent durability and high thixotropy provides alternative binder for 3D printing. The acid-base reaction between dead burnt MgO and K2HPO4 is intense and the retarding effect is limited in practical cases. This paper presents the investigation of MKPCs incorporating MgO-SiO2-K2HPO4 binders prepared with dead burnt MgO, soluble phosphate (K2HPO4•3 H2O) and silica fume (SF). The effects of magnesium-to-phosphate (M/P) mass ratio, SF and slag ratios on rheological properties and the printability were tailored and setting time reached to 50 min by increasing the alkaline environment of the solution. In addition, the pozzolanic activity of SF and slag were synergistically motivated and thus promoted the precipitation of K-struvite, MgSiO3 and C-(A)-S-H hydrates. Two-stage Athix values were calculated to describe the structuration rate. It is confirmed excellent thixotropy was dominated by early-age physical re-flocculation and later-age cement hydration. Although the structure deformation increased significantly as SF content increased, the beneficial effect of SF content on the increase of strength is significantly important than that of adverse effect on the buildability. Slag powder and fine aggregate were incorporated to make the binders more “printable”. A cylinder with 16 layers on optimum mixture was printed without deformation.