Changes In Ethanol Concentration Research Articles

Ethanol stability from nine years of a blind quality control program in blood alcohol analysis.

A blind quality control (BQC) program in blood alcohol analysis was implemented at the Houston Forensic Science Center (HFSC) in September 2015. By mimicking authentic toxicology blood evidence, the laboratory can perform a concurrent evaluation of their technical and administrative casework procedures and test the accuracy and reliability of their volatile analysis method in a format that is blinded to the analyst. From September 2015 to November 2023, HFSC's Quality Division submitted 1228 antemortem whole blood samples: 292 ethanol-negative samples and 936 ethanol-positive samples at sixteen target concentrations (0.051, 0.080, 0.100, 0.110, 0.120, 0.130, 0.150, 0.160, 0.170, 0.180, 0.190, 0.200, 0.230, 0.240, 0.250, and 0.260 g/dL). A second, unopened blood tube in 168 of the 1228 BQCs was also analyzed after 721-1140 days: 24 ethanol-negative samples and 144 ethanol-positive samples at five target concentrations (0.080, 0.100, 0.130, 0.180, and 0.240 g/dL). All 316 ethanol-negative samples remained negative. After 42-758 days, the average (median, range) change in ethanol concentration of the 936 positive samples was -1.4% (-1.3%, -12.0% to +8.4%) with a statistically significant difference (P < 0.001) observed for the gradual decline in blood alcohol concentration (BAC) over time. The average BAC percentage differences per target concentration, ranged from -6.4% (-0.008 g/dL) to +5.7% (+0.011 g/dL), were within HFSC's current measurement uncertainty (9.4% at k=3), showing no apparent correlation between the change in ethanol and the theoretical target concentration. As the analysis time between the two blood specimens from the same evidence kit extended, the loss in ethanol significantly increased (P < 0.001).

Interpretation of Ethanol Concentration Changes in Postmortem Blood and Vitreous Samples During Six Months of Refrigerated Storage

Interpretation of Ethanol Concentration Changes in Postmortem Blood and Vitreous Samples During Six Months of Refrigerated Storage

Investigation into Ethanol Concentration Changes of Ethanol–Water Solution Using Polarization Property Associated with Surface Plasmon Resonance in Aluminum Grating in Conical Mounting

Investigation into Ethanol Concentration Changes of Ethanol–Water Solution Using Polarization Property Associated with Surface Plasmon Resonance in Aluminum Grating in Conical Mounting

Comparisons ofBlood Alcohol Concentrations between Initial Testing andReanalysis from Unopened Tubes Preserved with 0.25% NaF Following Refrigerated Storage up to 3.93 Years.

Few studies support the usage of <1% nominal sodium fluoride (NaF) to preserve ethanol in antemortem blood. Of these studies, several are limited by short study durations of 90 days or less, and there is limited research of authentic samples preserved with <1% NaF. In this retrospective analysis, data from initial and reanalysis testing of blood alcohol concentration (BAC) in antemortem blood collected in 6 mL gray-top tubes (providing 0.25% nominal NaF) has been compiled, to evaluate changes in ethanol concentration that occurred after periods of refrigerated storage. The time between initial and reanalysis was determined by court request(s), and ranged 0.30-3.93 years. In each case, a previously unopened tube was selected for reanalysis testing. Comparable BAC values were found from initial testing, with BACs ranging from 0.025 to 0.394 g/100 mL, and reanalysis testing, with BACs ranging from 0.021 to 0.393 g/100 mL. Ethanol changes ranged from -0.013 g/100 mL (decrease) to 0.008 g/100 mL (increase). BAC reanalysis values that increased (n = 6) were within the uncertainty of measurement (UM) from the initial BAC test, i.e., were not statistically or analytically significant. For BAC decreases (n = 29), four test values exceeded the UM of the original test, with BAC losses ranging from 0.004 to 0.011 g/100 mL (relative percent changes 6.5-16.0% loss). The average ethanol change was -0.004 g/100 mL, which is comparable to or less than ethanol losses from studies using 1% NaF preservative of varying temperature and storage duration.

Microwave Grooved SRR Sensor for Detecting Low Concentration Ethanol-Blended Petrol

The rise in global energy demand due to economic development and an increase in population, have posed major concerns regarding energy security and environmental impact. Ethanol-blended petrol is an emerging alternative fuel that is considered cost-effective and environmentally friendly. However, the detection of low concentrations of ethanol in petrol is a significant challenge, especially as most nations mandate the blending of petrol with 5%-25% ethanol. This paper proposes a microwave sensor operating at 2.4GHz ISM band frequency to detect low concentrations of ethanol in petrol. The change in the magnitude of the reflection coefficient is adopted as the main sensing parameter. A single-frequency sensor composed of a square-shaped monopole loop antenna embedded with an SRR is proposed, which avoids the need for a wideband interrogation signal. The proposed design utilizes a filter paper wetted with the ethanol-petrol solution, placed along the split edge of the SRR, thus the use of complex and costly fluidic channels and space-consuming sample holders is avoided, bringing down the cost and complexity. The device dimensions are small, 4.2cm x 4.5cm. The sensitivity achieved in terms of amplitude change of the reflection coefficient is 2.83dB/5 % change of ethanol concentration in petrol, at a fixed frequency. In terms of the received power at 2.4GHz, the sensitivity is 2dBm/5 % change of ethanol concentration. Overall, this proposed sensor offers a simple, cost-effective, and efficient solution for detecting low concentrations of ethanol in petrol, which can aid in the adoption of ethanol-blended petrol as a viable alternative fuel.

Kinetic Study of Ethanol Dehydration to Ethylene and Diethyl Ether in Catalytic Packed Bed Reactor Over ZSM-5 Catalyst

Dehydration of ethanol is one of the crucial processes as it is considered a green route for producing ethylene and diethyl ether and is promoted mainly by economics and environmental appeal. In this study, different kinetic models for ethanol dehydration to ethylene and diethyl ether were developed based on two parallel reactions and different mechanisms. Additionally, a mathematical model of a packed bed reactor was also suggested based on a set of hypotheses for investigating the axial concentration profile of ethanol. Kinetic parameters of each model were estimated by nonlinear regression analysis of obtained experimental data reported in the literature at temperatures between (523.15 – 623.15) K. The analysis showed that the single-site model I for ethylene formation and dual-site (LHHW) model for diethyl ether formation gave the best representation of experimental data compared to other proposed models. Kinetic parameters were found to be in good accordance with the Arrhenius equation with acceptable straight-line plots, and they have been satisfactorily correlated as functions of reaction temperature. The mathematical model presented a smooth linear change in ethanol concentration at various temperatures. The AARD% obtained for each chosen ethylene and diethyl ether formation model were about (1.4502-2.5978) and (0.9135-2.9394), respectively.

Lack of fermentation in antemortem blood samples stored unstoppered in various locations.

A common defense challenge when antemortem blood ethanol results are presented at trial is the assertion that ethanol was formed in the blood tube after the blood draw through fermentation of the blood glucose by Candida albicans (C.Albicans). In contrast, decades of research into the stability of ethanol in antemortem blood collected for forensic purposes have consistently shown that any analytically significant change in ethanol concentration is a decrease and initially, ethanol-negative blood remains ethanol-negative with storage. For there to be any possibility of fermentation to occur by C.Albicans in an antemortem blood sample there must be a plausible mechanism for introduction of C.Albicans into the blood. One mechanism proffered at trial is environmental contamination resulting from ambient air drawn into the evacuated blood collection tube. Blood was drawn from ethanol-free individuals into 6 and 10-ml gray-top Vacutainer® tubes containing sodium fluoride and 6-ml Vacutainer® tubes without a preservative. Following the blood draws, the tubes were stored unstoppered at room temperature for 24 or 48 h in various locations. Following unstoppered storage, the tubes were stoppered and stored refrigerated (~4°C), left at room temperature (~22°C), or placed in an oven (37°C). The refrigerated blood was analyzed for ethanol using headspace gas chromatography after both 5 days and 32 months. Unrefrigerated blood samples were analyzed after being stored at room temperature or in an oven for up to 30 days. Ethanol was not detected in any of the blood tubes after storage regardless of storage time, storage temperature, or preservative concentration.

Non-monotonic effect of ethanol concentration on the spreading of an ethanol-water binary droplet impact on a supercooled surface

We investigate the effect of ethanol concentration on the spreading dynamics of an ethanol-water binary droplet impact on a supercooled surface. The maximum spreading factor, comprised of the maximum internal spreading factor and dimensionless fingering length, decreases and then increases with the ethanol concentration. It is attributed to the change in ethanol concentration which varies liquid viscosity and surface tension directly, and surface cooling which lowers the droplet temperature and thus varies liquid properties that further affect droplet spreading. The maximum internal spreading factor which is also non-monotonic with the ethanol concentration dominates the maximum spreading. The heat transfer analysis on droplet spreading shows that the temperature reduction of the droplet from impact to maximum spreading is non-monotonic dependent on the ethanol concentration, while shows different trends with surface cooling at various ethanol concentration. Deviations of the predicated maximum spreading factor, considering the droplet temperature reduction, obtained by reported correlations from the experimental ones in this study could be mainly due to the difficulty in accurately predicting the temperature-dependent spreading boundary layer thickness of the droplet. The maximum spreading time decreases and then increases with the ethanol concentration, while it keeps decreasing with the surface supercooling. A new correlation of the maximum spreading time is proposed by incorporating the coefficient of surface supercooling and capillary-inertial time of the droplet which involves density and surface tension.

The effect of ingredients’ concentration on nanoemulsion particle size of eucalyptus essential oil

This study aimed to determine the effect of different parameters affecting the particle size of eucalyptus-essential oil nanoemulsion using artificial neural networks. The formulation of nanomaterials used in this study included Tween 80 (as surfactant), ethanol (as co-surfactant), and eucalyptus essential oil (as internal phase), in water. To prepare the nanoemulsion, the mixtures were sonicated and the size of resulting nanoparticles were measured using dynamic light scattering (DLS). Then, the data were modelled using artificial neural networks. The results revealed that high Tween 80 concentration and low essential oil concentration had positive effects on reduction of particle size, while the change in ethanol concentration had no obvious impact on the size. The prepared nanoemulsions has the potential to be used in biomedical applications.

External ears for non-invasive and stable monitoring of volatile organic compounds in human blood

Volatile organic compounds (VOCs) released through skin (transcutaneous gas) has been increasing in importance for the continuous and real-time assessment of diseases or metabolisms. For stable monitoring of transcutaneous gas, finding a body part with little interference on the measurement is essential. In this study, we have investigated the possibility of external ears for stable and real-time measurement of ethanol vapour by developing a monitoring system that consisted with an over-ear gas collection cell and a biochemical gas sensor (bio-sniffer). The high sensitivity with the broad dynamic range (26 ppb–554 ppm), the high selectivity to ethanol, and the capability of the continuous measurement of the monitoring system uncovered three important characteristics of external ear-derived ethanol with alcohol intake for the first time: there is little interference from sweat glands to a sensor signal at the external ear; similar temporal change in ethanol concentration to that of breath with delayed peak time (avg. 13 min); relatively high concentration of ethanol relative to other parts of a body (external ear-derived ethanol:breath ethanol = 1:590). These features indicated the suitability of external ears for non-invasive monitoring of blood VOCs.

Phase Stability and Miscibility in Ethanol/AOT/n-Heptane Systems: Evidence of Multilayered Cylindrical and Spherical Microemulsion Morphologies.

We describe the effects of ethanol on the phase behavior of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in n-heptane. Using dynamic light scattering (DLS), molecular dynamics (MD) simulations, and nuclear magnetic resonance (1H NMR) spectroscopy, we investigate the aggregation behavior of AOT across a wide range of ethanol/AOT/n-heptane compositions. We conclude that reverse micelles do not form at any of the investigated concentrations. Instead, we observe the formation of other surfactant aggregate morphologies unique to this system, namely, multilayered cylindrical structures and spherical AOT-in-ethanol structures, which vary significantly with changes in ethanol concentration. We also identify mixed-solvent polarity as a driving factor for the surfactant behavior in the system. When the concentration of ethanol is 20 wt % or below, the system is inhomogeneous with varying sizes of AOT, ethanol, and AOT + ethanol aggregates, with the ethanol primarily exhibiting a cosurfactant behavior, almost exclusively binding at the surface of AOT aggregates. With increased ethanol concentration, the ethanol in the system also exhibits solvent-like behaviors in addition to the cosurfactant behaviors. Most significantly, when the ethanol concentration is raised above 35 wt %, the transition to solvent-like behavior allows AOT Na+ counterions to dissociate from the headgroups and they are dissolved in the ethanol. We use these results to construct a preliminary phase diagram for the ethanol/AOT/n-heptane system.

Physicochemical and aromatic characterization of carob macerates produced by different maceration conditions.

Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty‐six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2‐methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties.

Highly sensitive plasmonic biosensor based on ring shape nanoparticles for the detection of ethanol and D-glucose concentration

Today bioelectronics needs more sensitive sensors in their development. The main aim of this work is to design a highly sensitive optical sensor for the quantitative detection of ethanol and D-glucose through particular localized surface plasmon resonances (LSPRs) depending on shape and type of ring shape core@shell nanoparticles. The simulated plasmoniccore@shell nanoparticles consist of Ag or Au shell and air, Ag, or Au cores. The obtained results show the plasmonic resonance wavelength of the air@Ag nanoparticles strongly depends on their inner radiuses and using an air-core improves their resolution. Also, it is investigated that ring shape air@Agcore@shell nanoparticles are more sensitive to surrounding medium refractive index variation. It is showed that ~1.26 nm to ~6.27 nm and ~0.9 nm to ~2.6 nm in scattering plasmonic peak shifts are obtained corresponding to 1 g/dl to 10 g/dl D-glucose and 1 ml/dl to 10 ml/dl ethanol concentration changes. The sensitivity of the air@Ag nanostructure is 890.84 nm/RIU for D-glucose concentration changes from 0 to 1 g/dl. This higher sensitivity with the full width at half-maximum of 61.3 nm yields the figure of merit of 14.53. The findings of this work provide a novel perspective in the field of the optical sensors and can be applied to detect any other components.

Effect of Ethanol on the Photovoltaic Performance of ZnO Based Dye Sensitized Solar Cells

In this study, ZnO particles were grown at different ethanol–water concentrations by using a simple hydrothermal method at 97°C. The changes in structure and morphology of particles were investigated by varying the ethanol concentration. Scanning electron microscope images indicated that ethanol concentration was the main factor affecting the morphology and size of the ZnO particles. X-ray diffractometer pattern showed that crystal structures of the ZnO particles changed with the change in ethanol concentration of the starting solution. Zinc hydroxide phases rather than zinc oxide phases were found in ethanol-rich solutions during hydrothermal synthesis. Photovoltaic properties of the as-synthesized ZnO nanocrystals, as photoanode materials, were tested in dye-sensitized solar cells. Dye-sensitized solar cells were fabricated using a natural black carrot dye, and the performances of these cells were investigated for the electrode materials produced at different ethanol–water concentrations. The best solar energy conversion was obtained with ZnO electrodes fabricated at 100% ethanol concentration.

A Microfabricated Transparent Capacitor for Sensing Ethanol

The development of new sensing platforms could offer exciting opportunities for healthcare and environmental applications. In the last few decades, sensor device configurations have been limited owing to the use of electrochemical electrodes, resistors, and transistors. Capacitors are widely used for constructing various electronic devices. Here, we report for the first time the construction of a transparent interdigital transparent capacitor and its use for sensing ethanol. When the ethanol concentration changes, the dielectric properties of the capacitor change, resulting in the response of the impedance and capacitance. The capacitor shows a detection range of 0.1-1 volume fraction. It is expected that this paper could open up new opportunities for fundamental studies of more complex sensor configurations with a capacitor as one of the components and advance related healthcare and environmental applications.

Demonstration of Composition Changes in a Distillation Column by Use of Bromophenol Blue Indicator

In demonstrations of column distillation for the general public or in other demonstration settings, the audience often lacks the equipment or knowledge to access the distillation process. Distillation of solvents usually gives colorless solution. By adding bromophenol blue (BPB) to the distillation of water and ethanol, the authors have developed a setup sensitive to different ethanol concentrations, allowing direct visualization of the distillation process. The color in the distillation column changes from blue to yellow in the distillation column as ethanol concentration changes. Bromophenol blue indicator can also be used to quickly and semiquantitatively determine the ethanol concentration in binary ethanol–water mixtures in laboratory settings.

Synchronous synthesis and sensing performance of α-Fe2O3/SnO2 nanofiber heterostructures for conductometric C2H5OH detection

A synthesis procedure based on single-capillary electrospinning and hard-template method was provided to synthesize hierarchical α-Fe2O3/SnO2 nanofibers. The samples exhibit unique microstructure where α-Fe2O3 nanoparticles were evenly decorated on three-dimensional SnO2 fibrous scaffold. During preparation, the α-Fe2O3 nanoparticles and SnO2 nanofibers were formed synchronously. Within the composite nanomaterials, the Fe/Sn content ratio can be adjusted by changing the diameter of SnO2 nanofibers backbone. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and nitrogen adsorption-desorption analysis were used to characterize the structure of the synthesized products. By loading α-Fe2O3 nanoparticles, the grain growth of SnO2 was effectively restrained during heat treatment in air. The optimum Fe/Sn content ratio of α-Fe2O3/SnO2 heterostructures with the highest sensitivity was obtained through ethanol sensing measurements. Compared to pure α-Fe2O3 and SnO2 nanofibers, the binary composite nanofibers exhibits not only enhanced ethanol sensing response, but also higher dependence of response to the change of ethanol concentration. The remarkable improvement of sensing performance can be attributed to the synergetic effect of the component phases. The influences of heterojunctions on the gas sensing properties of α-Fe2O3/SnO2 nanofibers were discussed.

Pre-analytical factors related to the stability of ethanol concentration during storage of ante-mortem blood alcohol specimens

Sterile ante-mortem blood specimens were spiked with ethanol at the South African blood alcohol legal concentration limits of 0.20 g/L and 0.50 g/L and were stored in tubes containing sodium fluoride over a period of twenty-nine weeks under refrigeration (4 °C) and at room temperature (22 °C) to study the stability of the ethanol concentrations over time. Those stored under refrigeration were found to be stable, while a significant decrease in ethanol concentration at 99% confidence was observed in those stored at room temperature.Additional blood specimens, also spiked with ethanol, were inoculated with the dimorphic fungus Candida albicans at five different levels (1 × 106 cells/mL, 5 × 105 cells/mL, 1 × 104 cells/mL, 5 × 103 cells/mL and 5 × 101 cells/mL) and stored with and without sodium fluoride at 4 °C and 22 °C. The ethanol concentrations were monitored for nine weeks unless no fungal colonies were detected. Regardless of the presence or absence of NaF in samples – sterile or otherwise – storing specimens at 4 °C was sufficient to maintain the integrity of blood alcohol concentrations.The ethanol analyses were performed with an in-house validated isotope dilution gas chromatography-mass spectrometry analytical method on newly opened specimens once a week after which significance testing was performed to draw conclusions regarding changes in ethanol concentrations with measurement uncertainty in mind.

Effects of Ethanol on Flavor Perception in Alcoholic Beverages

In terms of both its physiological effects as well as its impact on flavor perception, ethanol is the defining component of alcoholic beverages. While ethanol’s effect on alcoholic beverage systems has been studied across a variety of disciplines, a comprehensive review of the literature is lacking. The aim of this paper is to review the current literature on ethanol’s effect on flavor perception. This paper reviews the literature, exploring ethanol’s effects on the areas of physiochemical properties, instrumental measurements of flavor release, and sensory evaluation across a variety of alcoholic beverages including beer, wine, and distilled beverages and how changes in ethanol concentration can affect flavor perception. Physicochemical properties such as the molecular level structure of water/ethanol matrices are significantly altered as a function of ethanol concentration. Of particular importance to flavor perception is the effect of ethanol on the release of aroma compounds into the headspace of the beverage. Both static and dynamic headspace systems have been studied. In general, increasing the concentration of ethanol decreases the volatile headspace in static systems, while it tends to increase the volatile headspace in dynamic systems. Most importantly, sensory studies have demonstrated that ethanol concentration significantly changes the flavor profile of beverages to the point where sensory panelists are able to identify and articulate these differences. The current literature demonstrates that ethanol can have a huge impact of flavor release and sensory perception of alcoholic beverages. Additionally monitoring ethanol’s effects in systems as close to real life as possible (i.e., dynamic vs static evaluation) is important. Even with the extensive knowledge in the area, there are still many gaps in our understanding of ethanol’s effects on the flavor of alcoholic beverages. Ethanol has been shown to have a tremendous influence on flavor release and subsequent chemosensory perception in alcoholic beverages. Changes in ethanol concentration can affect consumers’ perception of alcoholic beverages in terms of aroma, taste, and mouthfeel.

Biochemical markers to predict internal browning disorders in 'Rocha' pear during storage under high CO2.

The aim of this study was to identify biochemical markers to predict internal browning disorders (IBD) in 'Rocha' pear. Fruits from five orchards were stored for 45 days under cold air followed by 100 days in browning-inducing controlled atmosphere (CA) conditions (1 kPa O2 + 10 kPa CO2 ). Relationships between concentrations of ethanol (EtOH), acetaldehyde (AcDH) and ascorbic acid (AA), activities of peroxidase (POX) and polyphenoloxidase (PPO) and IBD incidence were established. The partial least square (PLS) model using the most promising markers, EtOH and AcDH, explained 89% of the variance in IBD incidence, whereas the univariate models based on the same markers explained between 89 and 94%. In contrast, the models based on AA levels and AA depletion rate only explained 57 and 82% of the variance in IBD incidence respectively. Model validation confirmed the robustness of EtOH for the prediction (R2 = 0.91, RMSE = 11.1) and allowed proposing a threshold level of 30 µL EtOH L-1 above which IBD may occur. Using this threshold value, the storage time limit associated with the occurrence of the first IBD symptoms was predicted with an acceptable RMSE of 9 days. This work clearly identifies biochemical IBD markers for 'Rocha' pear and shows that dynamic changes in ethanol concentration during the beginning of storage may be used to predict IBD development. Therefore the results presented herein represent a major step forward in the prediction of IBD in 'Rocha' pear. © 2017 Society of Chemical Industry.