Potassium Phosphate Research Articles

Influence of slag on water resistance of magnesium silicon potassium phosphate cement

The poor water resistance of traditional magnesium phosphate cement (MPC) limits its wider application in engineering fields. So far, research on enhancing the water resistance of MPC has been relatively limited. Therefore, this paper optimizes the slag content based on magnesium silicon potassium phosphate cement to prepare slag-magnesium silicon potassium phosphate cement (S-MSPPC). The research results indicate that slag contains various active components, and its appropriate addition can refine the pore structure of the paste. With the increase in slag replacement rate, the paste setting time increases, and the fluidity decreases slightly. The hydration of silica fume to produce SiO(OH)3‐ and SiO2(OH)22‐ ions significantly enhances the alkalinity of the paste and provides conditions for activating the activity of the slag. The S-MSPPC hardened paste can maintain alkalinity for the long term. Moreover, the water resistance of the S-MSPPC paste was significantly improved while ensuring mechanical properties. The water resistance coefficients of S-20 with 20 % slag increased by 49.23 % and 40.64 % at 28 days and 56 days compared to the reference group S-0. This improvement was due to the participation of silica fume and slag in the hydration reaction to form M-S-H and C-(A)-S-H gels in the paste. These gel products fill the pores and microcracks in the paste, optimize the pore size distribution, reduce porosity, and enhance density. In addition, the alkaline environment within the paste effectively slows the dissolution rate of K-struvite in water, further enhancing the water resistance of S-MSPPC.

Shape-controllable synthesis of lignin-derived boron-doped nanoporous carbons for dye adsorption and electrochemical H2O2 production

Lignin-derived nanocarbon materials (LNCMs) have attracted intense attention due to their excellent properties and promising applications in renewable energy technologies. However, lignins tend to melt and agglomerate during pyrolysis, make it difficult to control the morphology and pore structure of the resulting carbon. In this study, boron-doped porous nanocarbon (BFC) in various shapes (sphere, band, and sheet) were synthesized using ammonium borate as a crosslinking agent to prevent lignin melting, assisted by liquid nitrogen freeze-drying and potassium phosphate (KP) templating. The effects of BFC structure on methylene blue adsorption and electrochemical generation of H2O2 were investigated. The results show that KP-1/1-8BFC exhibits a high specific surface area (912.89 m2/g) and a hierarchical micro-mesoporous structure, achieving a remarkable adsorption capacity of 473.9 mg/g for methylene blue and rapid kinetics. The selectivity of KP-1/20-8BFC for electrochemical production of H2O2 reaches 85 %. This study offers theoretical guidance for the controllable synthesis of LNCMs, contributing to the advancement of sustainable energy solutions.

Physical properties of tween 20 + di-potassium hydrogen phosphate anhydrous (or tri-potassium phosphate 1,5-hydrate) + water from 288.15 K to 318.15 K

ABSTRACT The present study investigates the characterisation of binary and ternary mixtures involving a surfactant such as Tween 20 and various potassium salts in aqueous solutions. The ternary mixtures can form two distinct immiscible liquid phases. Several physical properties, including refractive index, density, and speed of sound, were measured, and derived properties such as excess molar volume and isentropic compressibility were calculated. The research focuses on the behaviour of aqueous binary and ternary mixtures composed of Tween 20, salts (di-potassium hydrogen phosphate anhydrous and tri-potassium phosphate 1,5-hydrate), and water in their homogeneous phases. It examines the influence of the surfactant and salts and the effect of temperature on these physical properties for homogeneous mixtures. Additionally, the physical properties of the equilibrium phases were determined to cover all the homogeneous zones comprehensively.

Development and Validation of Novel RP-HPLC Method for the Simultaneous Estimation of Itraconazole and Secnidazole in Bulk and Pharmaceutical Formulations

Simple, accurate and precise RP-HPLC method for the simultaneous estimation of Itraconazole (ITZ) and Secnidazole (SEC) in bulk and pharmaceutical formulations has been developed and validated. The chromatographic analysis was performed on Shimadzu model equipped with SPD-20 AD UV detector, isocratic pump LC- 20 AD and loop injector. The chromatographic separation was performed using C18 column (250mm x 4.6mm i.d. and 5µm particle size). The analytes were monitored at 257nm using methanol: potassium dihydrogen phosphate buffer (PDP) pH 5.5 in the ratio of 90:10v/v with a flow rate of 1.5ml/min. The retention time was found to be 6.037 min for ITZ and 3.788 min for SEC. The linearity was found to be in the range of 10-50µg/ml for both ITZ and SEC with a regression coefficient of 0.999 and 0.998 for ITZ and SEC respectively. The method was validated in accordance with ICH guidelines for its linearity, precision, accuracy, robustness, ruggedness, LOD and LOQ. The recovery studies were carried out which confirmed the accuracy of the proposed method. LOD values for ITZ & SEC was found to be 0.583µg/ml and 0.241µg/ml, respectively. LOQ values for ITZ and SEC was found to be 1.749µg/ml and 0.732µg/ml, respectively. The developed method was also found to be precise and robust for the simultaneous determination of ITZ and SEC in bulk and pharmaceutical formulations.

Influence of Ca-substituted K-induced cluster defects on the electronic structure and optical properties of KDP crystals

Compensation mechanism following Ca substitution in K sites was computed using GULP. Utilizing density functional theory for three charge states, the impact of defect clusters CaK + VK/CaK + VH on potassium dihydrogen phosphate (KDP) crystals in both phases was assessed. Corrections to the band edge and defect formation energies were made employing hybridization floods HSE06 and FNV. Neutral and −1 valence defect states emerged. Cluster defects induced pronounced lattice distortion in PE-KDP. Notably, PE-KDP exhibited an additional photoemission of 2.89 eV, signifying a substantial structural impact. Comparative stability analysis favored FE-KDP, offering theoretical guidance for KDP crystal utilization.

Impact of PGRs, polyamines and potassium to improve pomegranate flowering behaviour, fruit set and fruit quality

Ever changing climate is affecting the flowering pattern in pomegranate worldwide. It is the need of the hour to find out some chemicals that can not only enhance hermaphrodite flowers and fruit set but also enhance fruit quality. The present investigation aimed to evaluate the effect of plant growth regulators (three), polyamines (two) and other chemicals (five) on photosynthesis, flowering ratio, fruit set and quality of pomegranate fruits. Pomegranate trees were treated at full leaf expansion stage. Potassium dihydrogen phosphate (5000 ppm), spermidine (1.5 ppm) and naphthalene acetic acid (NAA) (20 ppm) were the best treatments to significantly enhance hermaphrodite flowers, as the hermaphrodite to male flower ratio was 0.39, 0.37, and 0.35, respectively, compared to 0.22 in the control treatment. Except spermidine, NAA and paclobutrazol, all treatments increased the fruit setting significantly, with potassium dihydrogen phosphate (5000 ppm) being the most effective treatment with 66% fruit set compared to 43% in control trees. In mature fruits, compared to control, NAA enhanced total phenols, ascorbic acid and total antioxidants (3%, 15%, 7%, respectively) followed by ascorbic acid treatment (250 ppm); potassium dihydrogen phosphate (5000 ppm) and putrescine (44 ppm) enhanced the anthocyanin content and hence aril color significantly (11% and 10% respectively). Though the use of NAA in pomegranate production is commercial practice, two sprays of ascorbic acid can also be included to enhance the nutritional quality of fruits. Foliar application of potassium dihydrogen phosphate twice at flowering stage could be highly useful for quality pomegranate production due to the enhanced number of hermaphrodite flowers, fruit setting and fruit color. Overall, use of these chemicals can be beneficial to pomegranate farmers to get more remuneration from harvest.

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.