Acetone Water Research Articles

Antioxidant and Anti-Mutagenic Potential of Mint (Mentha Arvensis) and its Chemical Characterization by HPLC

Background: Mentha arvensis has been used for medicinal purposes by Asian countries for ages. It is used to cure various ailments such as diarrhea, asthma, piles, cancer, dementia, hyperglycemia, and aging. Aim: This study aims to evaluate the antioxidant and anti-mutagenic (geno-protective) properties of four different solvent extracts (methanol, ethanol, acetone, and distilled water). Methodology: The antioxidant properties were determined by DPPH and reducing power assays, while the DNA damaging assay was used to evaluate the anti-mutagenic activity. Results: Among the four extracts, the methanol extract of Mentha arvensis showed 30.48 ± 0.95 mg QE/gm of flavonoid, and the aqueous extract showed the highest total phenolic content (142.2±0.83 mg QE/gm) and total alkaloids content (78.2±0.21 mg TE/gm) compared to the other three solvent extracts. The ethanol extract of Mentha arvensis exhibited the maximum value for total tannin content (17.41±0.38 mg ETA/g CE) and reducing power (41.17±0.87 mg ETA/gm). It also exhibited significant geno-protective activity. Conclusion: These results indicate that among the four solvent extracts, the ethanolic extract of Mentha arvensis has the highest value for phenolic content. Moreover, all four solvents, except distilled water, showed valuable anti-mutagenic behavior. The HPLC results corroborate our findings, suggesting that these plants have great potential for use as antioxidant and anti-mutagenic agents. Keywords: Mentha arvensis, Antioxidant agents, Anti-mutagenic agents, Geno-protective activity.

A disparity in solvatochromism of C[dbnd]O and S[dbnd]O vibrational probe: A study of structurally similar acetone and dimethyl sulfoxide

Solvatochromic studies of small IR probes are beneficialto study the structural dynamics of biomolecules as well as measuring the strength of surrounding electric fields in condensed phases.Herein, we have investigated the CO and SO vibrational probes of structurally similar acetone and dimethyl sulfoxide respectively to compare the solvatochromism. Interestingly in water CO formed both one hydrogen bond and two hydrogen bond complexes wherein SO formed only two hydrogen bond complexes.Not only this, but we have also investigated how different solvents alter the IR spectra of the CO and SO vibrating modes during the interaction with α CH of acetone and DMSO respectively.The IR absorption spectra of CO of acetone altered after αdeuteration(acetoned6) in aprotic organic solvents as well as aqueous solvents. But, surprisingly for DMSO and DMSOd6, the IR spectra of SO mode remain intact during α isotopic exchange (CH3to CD3) in organic aprotic solvents but in strong coordinating polar protic solvents (D2O) it is altered remarkably. The equivalent frequency gap of CO of acetone and acetoned6 in organic solvents and water represent the no interaction of α CH/D with solvent molecules. Parallelly unaltered IR spectral signature of SO of both DMSO and DMSOd6 in aprotic organic solvent represents the stationary state of the ‘S’ atom and altered SO IR absorption in water signifies the different α CH and α C-D interaction with the surrounding water molecules. These results are the cautionary of perturbation on IR probe during α CH interaction with solvents as well as guest molecules.

Potential of Nutmeg (<em>Myristica fragrans</em> Houtt) Leaf Extracts as a Source of Functional Ingredients with Antibacterial, Antifungal and Antioxidant Activities

Purpose: The objectives of this study were to evaluate inhibition activities of acetone, chloroform, ethanol and hot water extracts of nutmeg (Myristica fragrans Houtt.) leaves against Salmonella enterica, Listeria monocytogenes, Shigella dysenteriae, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Aspergillus niger and, to assess the in vitro antioxidant activities and to discover the active compound profile of chloroform extract of nutmeg leaf. Research Method: Agar well diffusion and agar disc diffusion methods were used to evaluate the antibacterial activity and the antifungal activity of the extracts respectively. Antioxidant activities of the acetone extract were evaluated through DPPH, FRAP, ABTS+ radical scavenging and Ferrous Iron Chelating assays. The total phenolic content (TPC) of the acetone extract was determined using the Folin-Ciocalteu assay. Findings: All the extracts showed inhibitory activity for the tested bacteria at different intensities and it was found that the selection of the extraction solvent is important to get the maximum inhibition against different bacterium. Acetone and chloroform extract (20%) showed the highest inhibition against A. niger (49.42% and 51.52% respectively). Acetone extract showed strong antioxidant activities, 715.78 ±51.09 in FRAP (mg of Trolox /g of leaves), 65.56±0.93 in DPPH (mg of Ascorbic acid /g of leaves), 31.67± 0.49 in ABTS+ (mg of Trolox equivalent/g of leaves), 10.87±1.85 in Ferrous Ion chelating (mg of EDTA/g of leaves) and, higher percentages of total phenolic content of 895.12 ±44.24 TPC (mg GAE /g of leaves). Myristic acid was detected as the major compound (57.36%) in GC-MS analysis and that may be the major compound responsible that offers a great potential to use as antibacterial, antifungal and antioxidant agent of nutmeg leaf. Originality/ Value: Results revealed that the nutmeg leaf possesses marked biological activities and showed a great potential to use for the management of human pathogenic bacteria, plant pathogenic fungi, and oxidative stress-associated chronic diseases.

Highly Active Nanocrystalline ZnO and Its Photo-Oxidative Properties towards Acetone Vapor.

Zinc oxide is one of the well-known photocatalysts, the potential applications of which are of great importance in photoactivated gas sensing, water and air purification, photocatalytic synthesis, among others. However, the photocatalytic performance of ZnO strongly depends on its morphology, composition of impurities, defect structure, and other parameters. In this paper, we present a route for the synthesis of highly active nanocrystalline ZnO using commercial ZnO micropowder and ammonium bicarbonate as starting precursors in aqueous solutions under mild conditions. As an intermediate product, hydrozincite is formed with a unique morphology of nanoplates with a thickness of about 14-15 nm, the thermal decomposition of which leads to the formation of uniform ZnO nanocrystals with an average size of 10-16 nm. The synthesized highly active ZnO powder has a mesoporous structure with a BET surface area of 79.5 ± 4.0 m2/g, an average pore size of 20 ± 2 nm, and a cumulative pore volume of 0.507 ± 0.051 cm3/g. The defect-related PL of the synthesized ZnO is represented by a broad band with a maximum at 575 nm. The crystal structure, Raman spectra, morphology, atomic charge state, and optical and photoluminescence properties of the synthesized compounds are also discussed. The photo-oxidation of acetone vapor over ZnO is studied by in situ mass spectrometry at room temperature and UV irradiation (λmax = 365 nm). The main products of the acetone photo-oxidation reaction, water and carbon dioxide, are detected by mass spectrometry, and the kinetics of their release under irradiation are studied. The effect of morphology and microstructure on the photo-oxidative activity of ZnO samples is demonstrated.

Thermodynamic functions of succinic acid in acetone–water binary mixtures based on computation of KI & KII constants

Succinic acid is commonly used in various chemical, pharmaceutical, environmental and industrial activities and its reactivity is principally determined by the pK(I & II) values. Therefore, the dissociation constants of succinic acid have been determined in this study on the basis of emf measurements in both different acetone mole fractions and temperature range. The pK(I or II) values of the studied acids in acetone aqueous media were found higher than those obtained in other organic aqueous media with the same conditions (temperature and mole fraction of solvent). Moreover, (KI/KII) in 40 wt% acetone–water mixture was identified to follow succinic acid < malic acid < malonic acid < maleic acid owing to the stabilization of intramolecular hydrogen bonding. The free energy of transfer (ΔG0I or II) for succinic acid was increased with the increasing of pKI or pKII values due to the decrease in relative permittivity (εr) via increment of the acetone fraction in the aqueous medium. The trend of ΔS°I value among the studied acids were found to follow maleic < malic < succinic < malonic. ΔS°II values were characterized lower than ΔS°I due to possible solvent interactions with the acid anion (L2-). Therefore, ΔH°II values of the second dissociation process were identified lower than ΔH°I to favor an exothermic reaction.

Hetero-Aggregation-Induced Tunable Emission in Multicomponent Crystals

Crystal engineering is a green and convenient approach to designing desirable materials through rational manipulation of intermolecular interactions. We have reported the lesser reported sulfonate–pyridinium intermolecular interaction for the design and synthesis of organic co-crystals with improved features. Here in we report the utilization of the interaction to tune the solid-state luminescence of organic precursor naphthalene disulfonic acid (NDSA-2H). Organic salts of NDSA-2H are synthesized and characterized with three isostructural bipyridyl co-formers: 4-phenylpyridine (4-PhPy), 2-phenylpyridine (2-PhPy) and 2,2′-bipyridine (2,2-bpy). Structural investigation validates aggregation of organic acid and base co-formers through sulfonate–pyridinium synthon and proton transfer between them. Compared to NDSA-2H, the molecular salts [(4-PhPy-H)2+(NDSA)2–·2H2O] (1) and [(2,2-BPY-2H)2+(NDSA)2–] (3) undergo a blue and red shift, respectively, while solid-state emission of [(2-PhPy-H)2+(NDSA)2–] (2) remains unaltered. This solid-state emission tuning is attributed to the different modes of crystal packing and arises from monomer emissions in 1 and 2 and excimer emission in 3. 3 also exhibits a relatively longer lifetime of 20.7 ns while 2 exhibits better quantum yields (ϕ = 22.7). Solution-phase photophysical behavior has been investigated for representative co-crystal system 3, after validation of its solution-phase integrity. 3 undergoes a hetero-aggregation-induced tunable emission (HAITE) phenomenon in the water–acetone system to exhibit maximum emission intensity at 90% volume fraction of acetone, which is further validated by the diffuse light scattering (DLS) and scanning electron microscopy (SEM) studies. 3 also exhibits solvatochromism in terms of emission intensity change with the nature of the solvent, being brightest in methanol (ϕ = 29.3) and very dim in water (ϕ = 10.1).

&lt;i&gt;In Vitro&lt;/i&gt; Evaluation of the Effects of Different Chemical Solvent Agents on Shear Bond Strength of Ceramic Orthodontic Brackets

In this study, the effects of different chemical solvents such as acetone, ethanol, dimethyl sulfoxide (DMSO), peppermint oil, and hot water on the shear bond strength (SBS) of mechanically and chemically bonded ceramic brackets were examined. Their use for facilitation of the debonding process in practice was evaluated regarding the purposes of this study. One hundred and thirty-two human premolar teeth extracted for orthodontic purposes were randomly divided into 11 groups. SBS were applied using a universal test machine. The amount of residual adhesives was determined through adhesive remnant index scoring. Scanning electron microscopy (SEM) images were examined to determine the effects of solvents on the enamel surface. In all test groups, the highest SBS values were found in the ethanol 5- and 15-minutes groups. SEM examination showed micro-cracks in all groups. Increased SBS values were also found in 5- and 15-minutes groups of hot water and DMSO, while both peppermint oil groups had similar SBS values as the control group. SBS values of both acetone 5- and 15-minutes groups were found to be lower than the control and other groups. Acetone application for 5 or 15 minutes before debonding of ceramic brackets could be an alternative clinical approach to prevent enamel damage and facilitate debonding.

Evaluation of Helichrysum arenarium flower exudate as an inhibitor on Lolium perrene seed germination under laboratory conditions

Abstract Compounds accumulated on the surface of plant tissues and structures like glandular trichomes and thin epicuticular layer are defined as exudate, external, superficial. They exhibited important protective activities - antifungal, antibacterial, insect antifeedant, larvicidal, antiplasmodial, and UV protective. The exudate obtained from Helichrysum arenarium flowers was evaluated for its inhibitory activity on germination and initial radicle elongation of Lollium perrene seeds. The experiment was done in vitro in Petri dishes. The exudate, in water–acetone mixture (99.5:0.5), was assayed at concentrations of 1, 3, 5, 7, and 10 mg/mL. The chemical composition of the exudate was analyzed by GC/MS. Exudate solution with 5 mg/mL concentration was found to cause more than 90% of seed germination inhibition. At the same concentration, complete inhibition of root growth was observed. The main bioactive component of exudate was identified as flavonoid aglycone–naringenin. The inhibitory activity of H. arenarium on seed germination was investigated for the first time in the present study.

Antibacterial Potential of Marine Brown Algae Turbinaria Conoides Against Bacteria Associated with Diabetic Foot Ulcer

The marine brown algae Turbinaria conoides was extracted with different solvents, viz., acetone, ethanol, methanol and distilled water. The extracts were screened for the presence of various phytochemicals and examined for antibacterial activity by agar well diffusion method. Diabetic foot ulcer (DFU) associated bacteria and their respective standard strains, such as Staphylococcus aureus ATCC 5923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 700603 and Enterococcus faecal ATCC 25922 were used as test bacteria. Among the different solvent extracts, the aqueous extract possessed the maximum zone of inhibition against both test and standard bacterial strains. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the aqueous extract against test pathogens were 128-4μg. The eluent mixture for separating the active fraction was selected by thin layer chromatography (TLC), which was found to be n-hexane: ethylacetate (6:4) with a maximum of four spots. In column chromatography, 25th -27th-minute fractions showed maximum antibacterial activity against all the DFU bacterial strains. Our study aims to find the use of T. conoides for treating DFU-associated bacterial infections. The objectives include exploring different solvent extracts of T. conoides for antibacterial activity and characterization of bioactive metabolite.

Measurement of Complex Permittivity for Rapid Detection of Liquid Concentration Using a Reusable Octagon-Shaped Resonator Sensor

Substrate-integrated waveguides (SIWs) are widely used in microwave systems owing to their low cost and ease of integration. In this study, an SIW-based resonator that reacts to the complex permittivity variation of solutions with dimensions of 79.2 mm × 59.8 mm is introduced. This octagon-shaped sensor can be installed on a preliminary monitoring system to test water quality by observing the parameter variations caused by external factors. The resonant structure was used to test different concentrations of ethanol-water and acetone-water mixtures for verification. The resonant frequency and quality factor (Q-factor) were found to vary with the relative complex permittivity of the liquid in the S-band, and the electric field distribution varied when liquid droplets were placed in the center of the substrate. The designed sensor operates at 2.45 GHz in the air, and the observed minimum resonant frequency shift with liquid was 15 MHz. The measurement error was approximately 3.1%, and the results reveal a relationship between the resonant frequency and temperature as well. Considering the observed sources of error, the measured relative permittivity is consistent with the actual values. The proposed sensor is economically convenient and suitable for various test environments.

Continuous Counter-Current Multistage Microextraction in a Novel Tube-In-Tube Microextractor

Counter-current operation has been widely applied to enhance the extraction efficiency for systems with low distribution coefficients, which was hindered in microextraction because viscous force and surface tension dominate over gravity and inertial force. In this study, a novel design of a tube-in-tube microextractor relying on a poly tetra fluoroethylene membrane to construct a stable interface was proposed to conduct continuous counter-current extraction. Extraction kinetics for two systems with different distribution coefficients, membranes with different pore radii, and three flow rate ratios were measured as a function of residence time. For the system that toluene was used to extract 0.06 wt % phenol in water, 4.1 stages of extraction efficiency were achieved at a residence time of 9.8 min. A challenging case study (50 wt % acetone–water–toluene) was subsequently conducted to prove the high applicability for emulsion systems of this special microextractor. Lastly, a mathematical model was established and the predicted results of three flow rate ratios are in good agreement with experimental results.

Eco-Friendly Valorization and Utilization of Plant Waste as a Source of Tannin for Leather Tanning

In the present study, bark, which is the waste part of a tree, was utilized as a source of tannin for leather tanning after its value addition. The barks of Acacia nilotica L. and Eucalyptus globulus, which are abundantly available in Pakistan, were selected in this study. Different extraction techniques including mechanical, soxhlet, reflux and ultrasonic extraction were used for the extraction of tannin from the selected barks. The medium of extraction included aqueous as well as different solvent mixtures in different ratios. The solvent mixtures used in this study were methanol-water and acetone–water. The methanol–water ratio was kept (50:50) and the acetone–water ratio was maintained at (50:50 and 70:30). In the first step, the process of extraction was optimized for solvent mixtures and extraction time by taking a fixed dose (5 g) of each bark and a fixed volume of each extracting solvent mixture (150 mL). The total phenolic contents (TPC) of the bark extracts were determined by colorimetric assay (as mg GAE/g bark), taking gallic acid as the reference standard. The tannin contents (TC) of the bark extracts were determined by using the standard hide powder method (SLC 117). It was concluded that among the different extraction techniques, and among the solvent mixtures acetone–water in ratio (70:30), ultrasonic extraction resulted in maximum extraction of tannin (196.1 and 125.2 mg/g), respectively for A. nilotica and E. globulus. FTIR analyses of the dried extracts obtained from both barks were compared with FTIR of the most commonly used commercial vegetable tanning agent in the leather industry, i.e., mimosa. Results were comparable, which confirmed the presence of condensed tannin in both barks. The extracted tannin was applied on a pickle and wet blue leather to evaluate its tanning and re-tanning capability. Mimosa, the most abundantly used vegetable tanning material in the leather industry, was applied as a reference standard on the same pickle and wet blue leather for comparison. Different physical properties, such as leather shrinkage temperature, leather softness, tensile strength, percent elongation and breaking strength, were measured to evaluate the tanning efficacy of the extracted tannins. The results showed that tannin obtained from A. nilotica showed comparable physical properties to those of mimosa. It was concluded from the results that tannin obtained from locally available bark, i.e., A. nilotica, can be utilized as a vegetable tanning agent for the leather industry.

Impact of different solvents on extraction yield, phenolic composition, in vitro antioxidant and antibacterial activities of deseeded Opuntia stricta fruit

Opuntia stricta the shrubby plant is naturally occurring in all parts of the world used as popular ornamental and is known to have medicinal properties due to its phytochemical compositions. In this study, the effect of solvents (80% ethanol, 80% methanol and 80% acetone (v/v) in water) on the extraction yield, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity and antibacterial activity of Opuntia stricta fruit were investigated. For the antioxidant activity assay, three different in-vitro methods DPPH, ABTS and FRAP were followed. The One-way ANOVA calculations showed that the extraction solvents influenced greatly and significantly the TPC, TFC and antioxidant capacity. Overall, 80% ethanol showed highest percentage of extraction yield while 80% acetone extract showed the lowest extraction yield but the highest TPC, TFC and antioxidant activity of Opuntia stricta fruit. In addition, Pearson’s correlation analysis proved a strong correlation between TPC, TFC and all antioxidant methods used. The antibacterial tests demonstrated that 80% methanol and 80% acetone extracts exhibited the highest zones of inhibition (11.66 and 11.33 mm respectively, p > 0.05) against Salmonella thyphimurium. Likewise, the 80% acetone extract revealed the best inhibitory effect contra Escherichia coli (p > 0.05) with an inhibition zone of 11 cm. Unfortunately, it was observed that gram-positive bacteria were less sensitive to all Opuntia stricta extracts compared to the gram-negative bacteria.

Development of a comprehensive method for hair and nail analysis using laser ablation-inductively coupled plasma-mass spectrometry

Hair and nails have been increasingly used in human biomonitoring (HBM). The advantages of these samples are non-invasive sampling, stability, and ease of storage. Elemental analysis using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a promising approach to retrieve information about long-term exposure to toxic elements; however, the lack of standardized analytical protocols hinders its application. In this work, Mn, Cu, Zn, Sr, Y, Pb and U were selected as model elements for developing analytical methods. Several critical aspects of the method were evaluated. We found that line scan resulted in higher reproducibility in nail analysis as compared to spot scan. Nail samples with a thickness of 0.5 mm were found to be best for LA-ICP-MS analysis. Regarding the sample cleaning, contaminants on hair were effectively removed by successive washing of acetone and ultrapure water; results were validated by the cross-section images of hair. Pre-ablation with a laser energies of 0.06 mJ per pulse and 1.03 mJ per pulse using higher scan rate and spot size were shown to be an effective method to remove the contaminants on undyed nails and dyed nails, respectively. Dried droplet calibration using element-enriched filter paper as calibration standards was developed for the quantification of elements. A new preparation of pressed pellet of hair CRM powder with sodium tetraborate was employed to validate the method. The recoveries of the model elements ranged from 97.2 to 105.4 %. Our study demonstrates that LA-ICP-MS can be used for high throughput elemental analysis of hair and nail samples, and has potential application in future HBM studies.

Low-Temperature Phase Equilibria in an Ethylene Glycol–Acetone System

An ethylene glycol (EG)–acetone (AC) system is studied via differential scanning calorimetry in the −140 to +40°С range of temperatures. A phase diagram is plotted over the range of concentrations. It is found that the mixtures in the system are supercooled by more than 30°C. Low-temperature melting is recorded in the region around −98°C, which corresponds to the eutectic point temperature. The devitrification of rapidly cooled samples is observed in the range of concentrations up to ~21 mol % AC, and the temperature of devitrification is determined (Tg ~ −120°C). The plotted phase diagram of the EG–AC system is compared to a water–acetone phase diagram.

Antioxidant activity and phytochemical analysis of fennel seeds and flaxseed.

Natural herbs are now receiving more attention due to the growing demand for their antioxidant properties. This study compared flaxseed and fennel seeds for their nutritional composition, bioactive moieties, and antioxidant activity-the study comprised two different phases. According to methods, phase I analyzed flaxseed and fennel seeds for proximate composition, mineral profile, dietary fiber, and amino acid content. In phase II, seeds were extracted using three different solvents, i.e., ethanol 80%, acetone 80%, and distilled water, to probe the total phenolic and flavonoid content. Antioxidant activity was measured using DPPH and a FRAP in the final phase. Current study revealed that flaxseed had higher protein (17.33 ± 0.02%), fat content (36.76 ± 0.02%), potassium (763.66 ± 4.04 mg/100 g), iron (5.13 ± 0.03 mg/100 g), phosphorus (581.46 ± 4.07 mg/100 g), magnesium (406.60 ± 5.12 mg/100 g), and zinc (3.30 ± 0.49 mg/100 g), respectively. In fennel seed, high dietary fiber (53.2 ± 0.01 g/100 mg), calcium, manganese, and sodium (588.93 ± 7.77, 20.30 ± 0.95, and 57.34 ± 0.33 mg/100 g, respectively) were found. Acetone showed better extraction efficiency than acetone, ethanol, and distilled water. Moreover, acetone flaxseed extract showed higher total phenolic content (84.13 ± 7.73 mgGAE/g), flavonoid content (5.11 ± 1.50 mgQE/g), and FRAP (5031 ± 15.92 μMFe2+/g) than fennel seed extract. This study showed that, among both herbs, flaxseed extract may have pharmacological potential in preventing illnesses and may be suggested for use in the food industry as a natural antioxidant.

Reactive Compatibilization of Impact Copolymer Polypropylene and Organically Modified Mesoporous Silica to Prepare Composites Possessing Enhanced Mechanical Properties

Mesoporous silica was evaluated as functionalized filler in impact copolymer polypropylene (ICP) in its original form as well as after organic modification. Mesoporous silica was synthesized by base-catalyzed hydrolysis of tetraethyl orthosilicate in the water–acetone medium. The organic modification of mesoporous silica was carried out using commercially available silane with a terminal unsaturated bond and by synthesizing silane precursor by chemical treatment via TEMPO-initiated thiol–ene chemistry to introduce alkyl chains terminating in hydroxyl groups. The characterization for all types of mesoporous silica prepared was done using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), solid-state nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). ICP–mesoporous silica composites were prepared using 1, 5, and 10 phr mesoporous silica and organically modified mesoporous silica loading via reactive compatibilization and were tested for their thermal, morphological, rheological, and mechanical properties. The addition of mesoporous and organically modified mesoporous silica enhanced thermal stability and nucleation with respect to neat ICP. Tensile and flexural moduli were improved while maintaining their impact strength. Analysis of rheological properties revealed a rise in zero-shear rate viscosity in ICP–mesoporous silica composites. DMA studies showed higher storage and loss modulus with the addition of mesoporous silica in ICP.

Solvent Influence on the Magnetization and Phase of Fe-Ni Alloy Nanoparticles Generated by Laser Ablation in Liquids.

The synthesis of bimetallic iron-nickel nanoparticles with control over the synthesized phases, particle size, surface chemistry, and oxidation level remains a challenge that limits the application of these nanoparticles. Pulsed laser ablation in liquid allows the properties tuning of the generated nanoparticles by changing the ablation solvent. Organic solvents such as acetone can minimize nanoparticle oxidation. Yet, economical laboratory and technical grade solvents that allow cost-effective production of FeNi nanoparticles contain water impurities, which are a potential source of oxidation. Here, we investigated the influence of water impurities in acetone on the properties of FeNi nanoparticles generated by pulsed laser ablation in liquids. To remove water impurities and produce "dried acetone", cost-effective and reusable molecular sieves (3 Å) are employed. The results show that the Fe50Ni50 nanoparticles' properties are influenced by the water content of the solvent. The metastable HCP FeNi phase is found in NPs prepared in acetone, while only the FCC phase is observed in NPs formed in water. Mössbauer spectroscopy revealed that the FeNi nanoparticles oxidation in dried acetone is reduced by 8% compared to acetone. The high-field magnetization of Fe50Ni50 nanoparticles in water is the highest, 68 Am2/kg, followed by the nanoparticles obtained after ablation in acetone without water impurities, 59 Am2/kg, and acetone, 52 Am2/kg. The core-shell structures formed in these three liquids are also distinctive, demonstrating that a core-shell structure with an outer oxide layer is formed in water, while carbon external layers are obtained in acetone without water impurity. The results confirm that the size, structure, phase, and oxidation of FeNi nanoparticles produced by pulsed laser ablation in liquids can be modified by changing the solvent or just reducing the water impurities in the organic solvent.

Nanoscale carbon dot-embedded metal-organic framework for turn-on fluorescence detection of water in organic solvents.

An easy-to-use, highly selective, and real-time organic solvent quality assessment is desirable to detect water contamination in organic solvents. Herein, a one-step procedure using ultrasound irradiation was used for encapsulating nanoscale carbon dots (CDs) into metal-organic framework-199 (HKUST-1) to form CDs@HKUST-1 composite. The CDs@HKUST-1 exhibited very weak fluorescence due to photo-induced electron transfer (PET) from the CDs to the Cu2+ centers, acting as a fluorescent sensor in its off-state. The designed material can detect and discriminate water from other organic solvents, driven by turn-on fluorescence. This highly sensitive sensing platform could be applied for the detection of water in ethanol, acetonitrile, and acetone with wide linear detection ranges of 0-70% v/v, 2-12% v/v, and 10-50% v/v and limits of detection of 0.70% v/v, 0.59% v/v, and 1.08% v/v, respectively. The detection mechanism is attributed to the interruption of the PET process due to the release of fluorescent CDs after treatment with water. A smartphone-based quantitative test was successfully developed to monitor the water content in organic solvents utilizing CDs@HKUST-1 and a phone color processing application, thus making it possible to develop an on-site, real time and easy-to-use sensor for water detection.

An empirical experimental investigation on the effect of an external electric field on the behaviour of laser-induced cavitation bubbles.

This study is an attempt to empirically investigate the behaviour of laser-induced cavitation bubbles under the influence of an external electric field. As such two targets (copper and iridium) were subjected to a high-power Nd:YAG laser beam while being submerged in a liquid. Three different liquids were chosen for this purpose viz. acetone, ethanol, and distilled de-ionized water. The choice of the liquids was made with the underlying assumption that the conductivity of the liquids would play a significant role in responding to the applied external electric field and thus dictate the behaviour of the cavitation bubbles. A probe-beam method known as a beam deflection setup was employed for this experiment and the results were analyzed using the Rayleigh-Plesset model. The results revealed that the maximum radii of the cavitation bubbles increased in response to an increasing electric field. This effect was more pronounced in the presence of acetone medium and decreased successively while using ethanol and water media owing to their varying magnitudes of electrical conductivity. The bubble collapse speeds and their energies were also measured and similar trends were observed in both cases. The results from cavitation bubble dynamics were then applied to a Gilmore model and the sizes of the NPs synthesized using laser ablation with and without an external electric field were calculated using classical nucleation theory.