Water Content In Ethanol Research Articles

Simultaneous extraction of tocochromanols and flavan-3-ols from the grape seeds: Analytical and industrial aspects

Grape processing generates large amounts of by-products, including seeds rich in hydrophilic and lipophilic antioxidants. This study demonstrates, for the first time, that subjecting grape seeds to a single ultrasound-assisted extraction (UAE) with aqueous ethanolic solutions yields both flavan-3-ols and tocochromanols in the final extract. Notably, the water content in ethanol significantly influences the extractability of tocochromanols more than flavan-3-ols. Solid-to-solvent ratios of 1:50 to 1:2 were tested for both analytical and industrial applications. A sustainable analytical approach for recovering flavan-3-ols and tocochromanols using 60% and 96.4% ethanol extractions was validated and employed to profile nineteen genotypes of lesser-studied interspecific grape crosses (Vitis spp.). Different genotypes showed a wide range of concentrations of tocopherols (1.6–6.3 mg/100 g), tocotrienols (1.0–17.4 mg/100 g), and flavan-3-ols (861–9994 mg/100 g). This indicated that the genetic background and maturity of the plant material are crucial factors from an industrial perspective due to the initial concentration of bioactive compounds. Finally, the study also discussed the fundamental aspects of hydrophobic antioxidant extractability from the lipid matrix with aqueous ethanol solutions and the limitations of the workflow, such as the non-extractable tocochromanols and their esters and the losses of these lipophilic antioxidants during extraction.

Effect of water content in ethanol on flame front wrinkling and curvature in a spark-ignition engine using OH PLIF imaging

The production of ethanol fuel involves separating water and ethanol by distillation and dehydration in an energy intensive process. To reduce the carbon footprint, hydrous ethanol is seen as a promising alternative. This study focused on the effect of water content in ethanol on flame development in a single-cylinder optical spark-ignition engine. Ethanol with 0%, 4% and 10% water content per volume was used with Port Fuel Injection (PFI) and Direct Injection (DI) for homogeneous and heterogeneous mixture preparation. Tests were also conducted with iso-octane for comparison. Flames captured by Planar Laser Induced Fluorescence (PLIF) of OH were spatially filtered to remove scales larger than the flame size, then the flame brush was quantified in terms of thickness, crossing frequency between instantaneous and filtered contours, and curvature. Increasing water content resulted in slower flame growth, with 10% hydrous exhibiting marginally higher flame speed than iso-octane. PFI led to faster flame growth and thicker flame brushes than DI at the same timing after ignition. When the brush thickness was normalised by flame radius, all hydrous fuels and iso-octane exhibited similar values with PFI, whilst anhydrous ethanol exhibited the thickest normalised brush. The alcohols maintained similar normalised thicknesses with DI and iso-octane exhibited the thickest normalised brush. When flames of the same radii were considered with PFI at the same timing, the fuels with sequentially lower laminar burning velocity were associated with larger crossing frequency. For PFI, increasing water content resulted in decreased flame roundness irrespective of size, with the 4% hydrous and iso-octane exhibiting similar values. With DI, anhydrous ethanol flames were rounder than the 4% hydrous when averaged over all cycles, but marginally rounder than the 10% hydrous and iso-octane. Increasing water content widened the curvature distribution and increased the mean with PFI. Flame roundness decreased with increase in mean curvature and Lewis number for both PFI and DI.

Spectral response of sulfonated polystyrene photonic crystals with varying concentrations of ethanol

Modifying polystyrene (PS) spheres through sulfonation is a well-established method to enhance their hydrophilic properties, rendering them valuable in diverse applications. Fabrication of photonic crystals (PCs) with sulfonated polystyrene (SPS) spheres offers an important platform for sensing applications. The hydrophilic nature of such PC platform helps in improving the detection of water content. In the present work, monodispersed SPS spheres were synthesized by adjusting the duration of the sulfonation reaction on the PS spheres created via emulsifier-free emulsion polymerization. PC opal films were fabricated using self-assembled PS and SPS spheres. The opal films were characterized using various techniques, including Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), angle-resolved reflection spectroscopy (ARRS), zeta potential and dynamic light scattering, and the results were compared and analysed. The hydrophilicity of the opal films was investigated using the water contact angle measurement, and it was found to improved by sulfonation. The spectral response of the PC opal films was investigated by monitoring Bragg’s diffraction spectra from the films using UV–VIS spectrometer. As a demonstration of a specific application, the prepared PC opal films were used to measure the water content in ethanol. PS and SPS opal films exhibited a noticeable blue shift in their spectral response when the water content in ethanol was increased to 3.8% and 3.4%, respectively. The added hydrophilicity brought on by the attached sulfonic groups improved the SPS film’s sensitivity to the water in the ethanol. SPS spheres demonstrated an optical response over a significantly more extensive range of the water content in ethanol than PS, which has a limited response range of up to 50%. Sulfonating PS spheres enhances colloidal stability and minimizes the tendency for aggregation in solution. Sulfonation for more than 3 h is found to exhibit reduced mechanical strength. Though the sulfonation induces an increase in surface roughness, the quality of the ordered arrangement of the spheres remained the same in comparison with PS films. By taking advantage of SPS’s hydrophilicity, high reactivity, stability, and the possibility of attaching additional functional groups, the present study opens up new possibilities for sensing water content in ethanol.

Optimization of a Simple Analytical Workflow to Characterize the Phenolic Fraction from Grape Pomace

The recovery of polyphenols from grape pomace (GP) supports the promotion of sustainable bioeconomy. Accordingly, the development of pre-treatment and extraction techniques using low-solvent amounts and energy-efficient processes is highly desirable. In this work, a comprehensive strategy to maximize phenol extraction from two Umbrian red wine cultivars, Cabernet Sauvignon and Merlot, was proposed. Focus was paid to sample pre- (fresh, air-, oven- and freeze-dried pomace) and post-extraction (chemical- and enzymatic-hydrolysis) treatments. An experimental design was applied to optimize phenol recovery by ultrasound-assisted extraction: the variables water content in ethanol (20–80% v/v) and time (10–30 min) highlighted a critical influence on the total phenol content (TPC) selected as the response. β-glucuronidase hydrolysis provided the highest TPC and in vitro total antioxidant capacity also improving phenol identification and quantification via HPLC–DAD (particularly evident for freeze-dried Merlot and Cabernet GP, which gave a total phenolic content measured by HPLC equal to 1904.08 mg/g and 2064.64 mg/g, respectively). LC-HRMS/MS analysis allowed identity confirmation of the major phenols, and cytotoxicity assay highlighted the safety of the selected β-glucuronidase extracts towards Caco2 cell line. Ultimately, in the present work, we have addressed the importance of the recovery of bioactive compounds from grape pomace by proposing a comprehensive analytical strategy in which different methodological alternatives have been evaluated to preserve these compounds, in a frame of sustainability on a larger industrial scale.

The influence of water on size of the monodisperse polystyrene microspheres prepared by dispersion polymerization

AbstractPolystyrene microspheres with uniform sizes have a wide range of applications in biomedical engineering. However, detailed and systematic investigations on the influence of water content on alcohol/water systems are relatively scarce. In this study, the impact of trace water content on microsphere size was comprehensively examined, and a systematic exploration of the varying effects of different hydration levels on particle nucleation and growth mechanisms was conducted. When the water content increased from 0.1% to 0.4%, the microsphere diameter rapidly decreases from 3.6 to 2.71 μm. Correspondingly, the molecular weight increased from 29,797 to 69,186. However, within the water content range of 0.5%–14.5%, alterations in water content induced only slight variations in the microsphere diameter. The microsphere size, molecular weight, conversion rate, and reaction rate were compared in two stages. It was observed that the diminishing influence of water on the system was due to the changes in the main polymerization sites. Subsequently, the addition of water content up to 33.5% revealed an exponential decrease in the microsphere size with increasing water content in ethanol. This pattern was also observed in methanol and isopropanol, demonstrating its universality and predictability, making it applicable for precise prediction of microsphere size in different solvents.

High-resolution biosensing with C-band guided-mode Fano resonance in an all-dielectric structure

An all-dielectric Fano resonance sensor is proposed, and its sensing characteristics are numerically investigated in the near-infrared region. The proposed device comprises two planar waveguides and a grating. The coupling between high- and low-quality-factor guided modes of the waveguides leads to a sharp Fano resonance at the optical communication wavelength of . Owing to the transparency of constituent dielectric layers in the near-infrared region, a sharp, low-loss Fano resonance appears in the reflection spectrum, which is favorable in sensing applications. The proposed sensor can detect small changes in the refractive index of the sensing medium as low as . The high sensitivity of a structure is promising in biochemical applications, such as measuring the refractive indices of organic solvents, the level of water content in ethanol and aqueous solutions, and blood glucose levels. The refractive index sensitivity is as high as λ=1550nm, and a figure of merit of Δn=0.001 is achieved.

Yellow Carbon Dots for Fluorescent Water Sensing, Relative Humidity Sensing, and Anticounterfeiting Applications.

Most fluorescent probes based on carbon dots (CDs) fluorescence color or intensity change are still used for detection in solution, but in practical fluorescence detection applications, detection in the solid state is necessary. Therefore, a CDs-based fluorescence sensing device is designed in this paper, which can be used for water detection in liquid and solid states. Using oPD as a single precursor, yellow fluorescent CDs (y-CDs) were prepared by hydrothermal method, which can be used in the field of water detection and anti-counterfeiting by using its solvent-sensitive properties. First, y-CDs can be used to visually and intelligently detect the water content in ethanol. Secondly, it can be used to detect the Relative Humidity (RH) of the environment by combining it with cellulose to form a fluorescent film. Finally, y-CDs can also be used as a fluorescent material for fluorescence anti-counterfeiting.

Fluorescence studies of double-emitting carbon dots and application in detection of H2O in ethanol and differentiation of cancer cell and normal cell

Herein, phenylalanine-bound carbon dots (CDs) with dual fluorescence emission peak behavior were reported, one of which was excitation-dependent and the other was not. The amino and carboxyl groups on the surface of CDs had a certain influence on their fluorescence. When the amino and carboxyl groups on the surface of CDs were removed, their fluorescence was significantlyweakened. The prepared CDs had solvent effect, and the emission peak of CDs shifted according to the change of the polarity of the solvent. Based on this, a method was developed for detecting water content in ethanol using CDs as a ratio probe. The change in the ratio of the intensity of the two emission peaks corresponded to the change of water content in ethanol. The detection linearity was good. In addition, the resulting CDs had good biocompatibility and could be enormously transported into cancer cells by the amino acid transporter on the surface of cancer cells, while normal cells only had a small amount of CDsthroughendocytosis, which laid the base for the distinguishing cancer cells from normal cells. The unique fluorescence properties of the prepared CDs achieved their applications in both water detection and cell differentiation.

Optimization of Ultrasound-Assisted Extraction of Chlorogenic Acid from Potato Sprout Waste and Enhancement of the In Vitro Total Antioxidant Capacity.

Potato sprouts, an underutilized by-product of potato processing, could be exploited for the recovery of caffeoyl-quinic acids (CQAs), a family of polyphenols with well-recognized biological activities. In this work, the predominant compound of this class, 5-CQA, was extracted by Ultrasound-Assisted Extraction (UAE) under conditions optimized by an Experimental Design. The investigated variables solid/solvent ratio (1:10-1:50 g/mL), water content in ethanol (30-100% v/v) and UAE time (5-20 min) highlighted a critical influence of the last two factors on the extraction efficiency: extracts richer in 5-CQA were obtained with lower water content (30%) and time (5 min). The addition of ascorbic acid (1.7 mM) as anti-browning agent to the extraction solvent improved the extraction efficiency of 5-CQA compared to acetic and citric acids (3158.71 μg/mL, 1766.71 μg/mL, 1468.20 μg/mL, respectively). A parallel trend for the three acids and an increase in 5-CQA recovery was obtained with the use of freeze-dried sprouts (4980.05 μg/mL, 4795.62, 4211.25 μg/mL, respectively). Total antioxidant capacity (TAC) in vitro demonstrated UAE being a more valuable technique than conventional maceration. Furthermore, three-times-higher values of TPC (7.89 mg GAE/g) and TAC (FRAP: 24.01 mg TE/g; DPPH: 26.20 mg TE/g; ABTS 26.72 mg TE/g) were measured for the optimized extract compared to the initial one. An HPLC-DAD method was applied to monitor 5-CQA recovery, while an LC-HRMS/MS investigation allowed us to perform analyte identity confirmation along with detection of the glycoalkaloids α-solanine and α-chaconine. This evidence underlines the necessity to develop purification strategies in order to maximize the potential of potato sprout waste as a source of 5-CQA.

Aggregation emission of AuNCs induced by chitosan self-assembled multilayers and sensitive sensing for water content in ethanol.

AuNCs with chemical groups such as -NH2 and -COOH were synthesized using glutathione as the stabilizer and reducing agent. The aggregation emission of AuNCs in solution-induced self-assembled multilayers (SAMs) were first studied. Scanning electron microscopy and quartz crystal microbalance were used to characterize the morphology and aggregation process of AuNCs. Further AuNC SAMs were used for the solid-liquid interface sensing of water content in ethanol, and the sensitivity is obviously improved as compared with that in the pure solution phase. This aggregation emission induced by SAMs would have a good application prospect in analysis.

A New Dual-peak Fluorescent Probe for Water Content Detection Made From Taxus.

In this paper, the leaves of Taxus were used as the sole carbon source, and two kinds of carbon dots blue and red, with different properties, were synthesized by the hydrothermal method under different conditions. The red carbon dots were quenched in the water, and the blue carbon dots had stable fluorescence properties in water environment. The bimodal fluorescence probe formed by mixing could accurately and stably measure the water content in ethanol, which was in the range of 82.5%-100%, is highly correlated with the fluorescence intensity ratio (I481/I678) of mixed carbon dots under 390nm excitation light, with R2 = 0.995 and the detection limit as low as 0.31%. The experimental materials are environmentally friendly, low in cost, and simple to operate, as well as the water content measured by proportional fluorescence has high accuracy, which provides a new method for measuring moisture in ethanol.

A handy imaging sensor array based on the phase transformation from CsPbBr3 to CsPb2Br5: highly sensitive and rapid detection of water content in ethanol.

Detection of the water content in ethanol has become very important in many fields; however, well-established methods usually require complex strategies and devices. Herein, a simple and non-instrument methodology was developed for the determination of the water content in ethanol. In this work, a CsPbBr3@PVA imaging array sensor was constructed based on the fluorescence on/off mechanism and applied to the detection of water content for the first time. When preparing CsPbBr3@PVA, the photoluminescence of CsPbBr3 was quenched by water in PVA due to the decomposition of CsPbBr3. By employing ethanol with fast volatilization to remove water, the decomposed composition recrystallized and formed luminescent CsPb2Br5. When the water content in ethanol was increased, the degree of the recovered fluorescence drastically reduced. To develop a portable and easily-operated methodology, the pictures of the sensor array were captured using a smartphone and quickly analyzed with ImageJ to read the gray-level values for each sample. The latter displayed a good linear relationship (R2 = 0.995) with the water content increasing from 0% to 7% in ethanol, and a low limit of detection of 0.006% was achieved. Moreover, the sensor array showed advantages like a fast response speed (5 s), strong selectivity and application potential in real samples. This method does not require expensive spectrometers and professional personnel to operate, having the virtues of low cost, fast detection and high sensitivity.

Characterization of the Ethanol-Water Blend by Acoustic Signature Analysis in Ultrasonic Signals

The use of ethanol as fuel in Brazil stimulated the competition between distribution companies and resellers, which aggravated the practice of adulteration of fuels, aiming for illicit gains and tax evasion. The most common practice of adulteration in fuel alcohol is the addition of water. The classic techniques for measuring the water content in ethanol offer good precision and good detailing as to the presence of water. However, they present disadvantages such as the need for sample collection, long analysis time, in addition to the need for specialized laboratory and labor. This work aims to propose digital signal processing techniques to analyze and quantify the presence of water in ethanol fuel using a combination of Principal Component Analysis (PCA), and Singular Spectrum Analysis (SSA) applied on ultrasonic signals. This method resulted in the proposal of a new score, which relates to the ethanol/water ratio information present in the mixture. The results were promising when relating the proposed score to the presence of moisture in ethanol to a greater or lesser degree. Experiments performed prove the technique’s feasibility and pave the way for a new method for real-time monitoring.

Effect of water content in ethanol on spray formation at subcooled and flash-boiling conditions

Direct-injection spark-ignition engines can be more sensitive to fuel type as the time available for spray formation and mixing is rather limited. The challenge is further complicated by fuel stock which includes a significant bio-derived component in some markets to manage fuel sustainability. The thermophysical properties of bio-components like ethanol differ markedly from typical hydrocarbons found in gasoline like iso-octane. Moreover, the production of anhydrous ethanol fuel involves separating water and ethanol by distillation and dehydration in an energy intensive process. This study presents results from an optical investigation into the spray formation process of hydrous ethanol fuels with 4–15% water content per volume in direct comparison to anhydrous ethanol and iso-octane. Injection tests were carried out with 20–110°C fuel temperature at 1.0 bar and 0.5 bar gas pressure to mimic thermodynamic conditions of cold-start and fully-warm engine at low-load and wide-open-throttle operation. High-speed spray imaging was conducted along with droplet sizing by phase Doppler anemometry. The thermophysical properties of all fuels, including vapour pressure, density, viscosity and surface tension, as well as distillation curves, were obtained over a range of temperatures and the respective Reynolds, Weber and Ohnesorge numbers were considered in the analysis. At 20°C iso-octane and anhydrous ethanol exhibited similar spray plume penetration, whilst increasing water content in ethanol reduced spray penetration. At higher temperatures up to 90°C, anhydrous ethanol showed lower penetration than iso-octane whilst the hydrous fuels still exhibited lower penetration than anhydrous ethanol in sequence of increasing water content. At 110°C, the ethanol fuels showed signs of plume merging and spray collapse, particularly at 0.5 bar gas pressure, with clear differences from iso-octane. The degree of plume merging and collapse was stronger with increased water content. The cone angle for the hydrous fuels was higher than that of pure ethanol, with the 4% water content ethanol that was close to the azeotropic point showing wider cone angle at temperatures higher than 20°C, being distinctly higher at 90°C. Iso-octane had consistently smaller droplet Sauter mean diameter than the ethanol fuels. As the percentage of water content in ethanol increased there was an increase in droplet sizes at all conditions.

Ultrahigh sensitive long-period fiber grating-based sensor for detection of adulterators in biofuel.

An ultra-sensitive sensor based on dual resonance long-period fiber gratings has been fabricated for the detection of methanol and water content in ethanol. The developed sensor is compact in size and light weight and employs a highly accurate spectral interrogation technique for adulterant detection, increasing its applicability compared to conventional surface plasmon resonance based sensors, which are generally expensive, as they require metal film deposition. We demonstrate that the sensor is capable of achieving sensitivity of 802.66 pm/V% methanol and 749.06 pm/V% water in the ethanol solution. The estimated detection limit using the experimental data and spectral resolution of the interrogator is found to be ∼1.3×10-3V% in the 1300-1700 nm wavelength range. We also present the sensor's theoretical study, and good agreement is found between theoretical and experimental results.

A novel ratiometric fluorescent probe for water content in ethanol and temperature sensing

In this paper, two tetrahydo[5]helicene-based dyes (THH1 and THH2) were studied on their twist intramolecular charge transfer. And the water-soluble blue carbon dots (N-CDs) were synthesized. Considering that their different optical propeties, the ratiometric fluorescence probes N-CDs/THH1 and N-CDs/THH2 were constructed by mixing N-CDs and dyes simply. It was found that N-CDs/THH1 and N-CDs/THH2 could quickly and sensitively detect water content in ethanol, with linear range of 0.500–25.0 vol% and 0.500–30.0 vol%, respectively. What’s more, through the actual sample test, it showed that the detection had good accuracy and precision. At the same time, it was found that two ratiometric probes could also be applied to the thermometry with good reversibility based on optical temperature sensors.

Ratiometric dual-emission of Rhodamine-B grafted carbon dots for full-range solvent components detection

Quick and visual detection of component contents, such as water, in a mixed solvent is important for many practical applications, and a full range detection is especially preferred. In this work, a carbon dots based ratiometric fluorescent sensor was synthesized by grafting fluorescent group (Rhodamine B, RhB) on carbon dots, and the dual emission peaks exhibited a linear ratiometric response with the change of polarity and hydrogen bond of Solvent Hansen solubility parameters. This responsive behavior is attributed to surface state photoluminescence mechanisms, and has been used for the quantitative detection of water content in ethanol with an excellent linear relationship (R2 = 0.996), a low detection limit (0.2%), and a full detection range (0–100%). Furthermore, a paper-based ratiometric fluorescence sensing strip is also demonstrated, which exhibits good storage stability and sensitivity. This study suggests that RhB grafted carbon dots could be feasibly and effectively used as ratiometric fluorescent sensors for solvent content detection.

Design and development of fiber optic sensor for measurement of purity of ethanol

Pure alcohol (ethanol) has number of applications in automobile, chemical and pharmaceutical industries. Fiber optic sensor has widespread use due to its non contact type measurement in retro reflective configuration. This paper proposes non contact type refractometric fiber optic sensor for measurement of purity of alcohol manufactured in distilleries. This refractometric based sensor shows variation in the received light intensity with variation in water content of ethanol i.e. purity of alcohol. The sensor is studied and analyzed by performing simulation based on mathematical model developed using ray tracing technique. The sensor is fabricated and tested by preparing samples in the laboratory. The refractive indices are later measured using Abbe’s refractometer having the resolution of 0.001 in white light. Field tests are also carried out at the local distilleries. Experimental results show good agreement with the simulated results as well as with the conventional methods used in industry for measurement of the purity of alcohol. The sensor shows linear variation in the output voltage with the variation in alcohol purity of alcohol from 90% to 99%. The repeatability of the sensor is checked by repeating the experiment 60 times for each value of purity.

Kinetic modelling of the one-step conversion of aqueous ethanol into 1,3-butadiene over a mixed hemimorphite-HfO2/SiO2 catalyst

A kinetic model for the one-step conversion of ethanol into 1,3-butadiene over a mixed hemimorphite-HfO2/SiO2 catalyst has been developed, which, as a novelty, accounts for the effect of water content in ethanol on the performance of one-step catalysts, which is important when designing industrial processes. The model considers the formation of the main reaction products (acetaldehyde, water, hydrogen, 1,3-butadiene, ethene, diethyl ether and 1-butanol) as well as numerous minor products, grouped into three lumps (butenes, heavy compounds (C6+), and oxygenated compounds). A network of eight reactions is used to describe this complex reaction system. The rate of each reaction is modelled using a power-law kinetics with a corrective term to capture the effect of water on certain reactions. Experimental data on the effect of water and reaction conditions on the performance of the hemimorphite-HfO2/SiO2 catalyst were used for the regression and validation of the kinetic model. The results show that the model can predict well the effect of reaction conditions and water content in ethanol on the formation of major and minor compounds, except for butenes and heavy compounds. The modelling approach to build the kinetic model is expected to be valid for any other one-step catalyst.

Quantification of water in bioethanol using rhodamine B as an efficient molecular optical probe

The present study reports the use of ultraviolet–visible absorption, steady-state fluorescence, and time-resolved fluorescence to determine the water content in ethanol by using Rhodamine B as an optical probe. The experiments were performed by preparing water/ethanol blends with different percentages of water in the presence of the optical probe. The absorbance, fluorescence intensity, and fluorescence lifetime values were linearly dependent on the water content in the blends in the range between 0 and 10% (w/w). The results also revealed that the three techniques have a limit of detection for water ≤ 1.4% (w/w). Besides, molecular dynamics simulations were carried out to evaluate the interaction of RhB with water and ethanol molecules when subjected to different water content in the blends. The simulations revealed that water molecules perform well-oriented dipole-dipole interactions (hydrogen bonding) with chromophores/fluorophores groups of Rhodamine B, affecting its absorption and emission characteristics, and altering the microenvironment density and viscosity. The present findings point out that common optical techniques can be used to develop a simple, rapid, portable, and precise approach to monitor water in ethanol as far as RhB be used as a probe.