Simultaneous Determination Of Ethanol Research Articles

Simultaneous Determination of Ethanol and Methanol in Wines Using FTIR and PLS Regression.

Accurate quantification of ethanol and methanol is essential for regulatory compliance and product quality assurance. Fourier Transform Infrared Spectroscopy (FTIR) offers rapid, non-destructive analysis with minimal sample preparation, making it a promising tool for wine analysis. In this exploratory study, the use of FTIR and PLS regression for the simultaneous quantification of ethanol and methanol in wine samples of 11 different Portuguese mono-varietal wines and different vintages deriving from the same winery in Lisbon was investigated. A model was developed, demonstrating the feasibility of FTIR and PLS regression for the simultaneous quantification of ethanol and methanol in wine samples through dedicated models; it showed good prediction capacity for ethanol determination but poorer performance for methanol quantification. The model could be reliable enough for quality control in wine production, but to improve its performance should be enhanced in the future with more samples from different origins, wine types, and a wider concentration range in the case of methanol.

Assay of ethanol and congener alcohols in serum and beverages by headspace gas chromatography/mass spectrometry

The analysis of ethanol and of its congeners in blood plays an important role in forensic cases, especially when allegations are made that alcohol has been consumed after an accident. In alcoholic beverages, congener alcohols are by-products and are generated during fermentation. The assay of these compounds in serum samples and beverages has been previously performed using headspace-gas chromatography-flame ionization detection methods (HS-GC-FID). As an alternative, a robust headspace-gas chromatography-mass spectrometry (HS-GC-MS) procedure was developed and validated, which has the following advantages:•Simultaneous determination of ethanol, congener alcohols and other endogenous substances.•Reduction of matrix interference by increasing selectivity and specificity.•Clear separation of the positional isomers 3-methyl-1-butanol and 2-methyl-1-butanol.

Simultaneous determination of ethanol's four types of non-oxidative metabolites in human whole blood by liquid chromatography tandem mass spectrometry

The importance of ethanol non-oxidative metabolites as the specific biomarkers of alcohol consumption in clinical and forensic settings is increasingly acknowledged. Simultaneous determination of these metabolites can provide a wealth of information like drinking habit and history, but it was difficult to achieve because of their wide range of polarity. This work describes development and validation of a simple liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for 4 types of ethanol non-oxidative metabolites (ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters and phosphatidylethanols) in 50 μL of human whole blood. Pretreatment method, column and MS conditions were optimized. For the first time, the four types of ethanol non-oxidative metabolites with enormous discrepancies of property were simultaneously extracted and analyzed in one run within 40 min. The limits of detections (LODs) were among 0.1–10 ng/mL, and good linearity was obtained. Deviations in precision and accuracy were all lower than 15% at three QC levels. This method was then applied to two forensic samples, resulting in information on drinking habits and drinking time which were very useful for the interpretation of the blood alcohol results.

Breath-Based Electrochemical Sensors: Simultaneous Determination of Ethanol and Smoking By-Products

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A new validation approach applied to the GC determination of impurities in organic solvents

Organic solvents such as methanol, acetone, dichloromethane or toluene are frequently used in the pharmaceutical industry. The manufacturing of new active pharmaceutical ingredients (APIs) under GMP conditions commands to control adequately the quality of the different ingredients happening in the synthesis. Organic solvents have therefore to be controlled and their purity has to be determined before any GMP synthesis. A selective gas chromatography (GC) method has been developed to determine the purity of acetone, dichloromethane, methanol and toluene. Using this method, the main contaminants of each organic solvent can be quantified. Moreover, the developed method allows the simultaneous determination of ethanol, isopropanol, chloroform, benzene, acetone, dichloromethane, methanol and toluene. Propionitrile was used as the internal standard. The separation was obtained on a CP-SIL 8-CB low bleed/MS column (60 m × 0.32 mm i.d. × 1.0 μm coating thickness). The GC method was fully validated using a new approach based on the accuracy profile as a decision tool. The determination of β-expectation tolerance intervals for the estimation of total error – including both bias and precision – is used to better reflect the actual performances of the method, which is definitively the objective of the validation. The different validation criteria such as selectivity, response function, trueness, precision, accuracy, linearity or limits of detection and quantification were considered. The method was found to be able to quantitate with a good accuracy impurities around the 0.1% (v/v) concentration level for the different solvents.

Microdialysis for the determination of acetaldehyde and ethanol concentrations in the striatum of freely moving rats

The subject of the present paper is the simultaneous determination of ethanol (EtOH) and acetaldehyde (AcH) concentrations in the striatum of freely moving rats using an in vivo microdialysis followed by head-space gas chromatography (GC). Major operation conditions of GC were as follows: column, injector and detector temperatures 90, 110 and 200 °C, respectively; Supelcowax™ wide bore capillary column (60 m length, 0.53 mm i.d., 2 μm film thickness); carrier gas, nitrogen; flow rate, 20 ml/min. The recovery of EtOH and AcH at a concentration 40 mM and 250 μM, respectively, by microdialysis showed a maximum of 83.8±12.2 and 51.2±6.5%, respectively, at a flow rate of 0.8 μl/min. A good linear calibration curve in the concentration range of 5–50 mM for EtOH ( r=0.998), and 10–250 μM for AcH ( r=0.988) was observed. Microdialysates were collected for 10 min each after insertion of probe into the striatum. Rats were treated with cyanamide (100 mg/kg, a potent aldehyde dehydrogenase inhibitor) and 60 min later with EtOH (1 g/kg) intraperitoneally. A 10 min sample was about 8 μl. This volume was mixed with 40 μl of 0.002% t-butanol as an internal standard in 0.6N perchloric acid, and then analyzed by head-space GC method. The peak EtOH and AcH concentrations in the striatal dialysates reached maximum at 30 min, and then gradually decreased. This method represents a reasonable tool to quantify in vivo both AcH and EtOH levels simultaneously in rat brain.

Simultaneous Determination of Ethanol and Acetaldehyde in Liquor Using a Flow System Composed of Two Enzyme Reactors and an Octadecylsilica Column.

Simultaneous determination of ethanol and acetaldehyde was performed with an apparatus consisting of two enzyme reactors placed either side of an octadecylsilica column in a single flow line. The enzymes used were alcohol dehydrogenase for ethanol analysis, and aldehyde dehydrogenase for acetaldehyde analysis. The most favorable concentration of NAD+ in the carrier for the simultaneous determination of ethanol and acetaldehyde was studied in wine or sake, in which the ethanol concentration was much higher that that of acetaldehyde. An NAD+ concentration of 0.1 mM was adopted. To distinguish between NADH formed due to ethanol and that formed due to acetaldehyde, several buffers (pH 7.8) were also examined for use as the carrier medium, and triethanolamine buffer was found to be the most favorable. The calibration curve for acetaldehyde was linear (r2 = 1.000) in the range of 0.2-100 μM. With respect to ethanol, plotting the logarithm of the peak area versus that of the concentration gave a linear relationship (r2 = 0.997) in the range of 0.04-100 mM. This method was applied to the simultaneous analysis of ethanol and acetaldehyde in several types of liquor. The results were similar to those obtained using a commercially available test-kit method, suggesting the reliability and practicality of this method in analyzing real samples.

Simultaneous determination of ethanol and glycerol in wines by a flow injection-pervaporation approach with in parallel photometric and fluorimetric detection

A simultaneous method for the determination of ethanol and glycerol in wines based on the coupling of pervaporation-chemical derivatisation-photometric detection for ethanol and biochemical derivatisation-fluorimetric detection for glycerol is proposed. After separation by pervaporation the ethanol is collected in a K 2Cr 2O 7 acceptor stream and the Cr 3+ formed is driven to the spectrophotometer and monitored at 600 nm. The determination of glycerol is based on its oxidation by oxidised β-nicotinamide adenine dinucleotide (β-NAD +) catalysed by glycerol dehydrogenase immobilised on controlled-pore glass, the reduced form of the coenzyme (NADH) being spectrofluorimetrically monitored ( λ ex=340 nm, λ em=460 nm). The linear determination range is between 1–20% for ethanol and 2–8 g l −1 for glycerol, with RSDs 3 and 2%, respectively. The method applied to red and white Spanish wines, compares well with the official methods for these analytes.

Simultaneous biosensing of ethanol and glucose with combined use of a rotating bioreactor and a stationary column reactor

The simultaneous determination of ethanol with electrochemical detection and glucose with chemiluminescence detection was performed with combined use of a rotating bioreactor and a stationary column reactor. Continuous-flow/stopped-flow sample-reagent processing was proposed in this system. In electrochemical detection of ethanol, when a sample was injected and arrived just above the rotating bioreactor, the working solution was stopped for a certain period. The rate of increase of oxidation current of hydrogen peroxide which was produced with the ethanol/alcohol oxidase reaction was measured. In the chemiluminescence detection of glucose, the working solution was propelled again, and the glucose in the sample was passed through the glucose oxidase immobilized column. The hydrogen peroxide produced was measured by chemiluminescence with luminol/peroxidase. The method is applied to the determination of glucose (ca. 2%) and ethanol (13–16%) in alcoholic beverages.

Application of multivariate calibration to the simultaneous routine determination of ethanol, glycerol, fructose, glucose and total residual sugars in botrytized-grape sweet wines by means of near-infrared reflectance spectroscopy

The simultaneous determination of ethanol, glycerol, fructose, glucose and residual sugars in botrytized-grape sweet white wines was performed by means of near-infrared reflectance using 19 interference filters and a partial least squares (PLS) model in latent variables as a multivariate calibration technique. The results were compared with those obtained using other multivariate calibration techniques, such as MLR, SWR and PCR, by means of a validation set of samples with known compositions. Ethanol, fructose and residual sugars were well predicted by all the multivariate techniques. Glycerol and glucose showed the highest prediction residuals. The technique may be of practical interest in the routine analysis of these types of wines with low cost in terms of samples, time and personnel.

Individual and simultaneous determination of ethanol and acetaldehyde in wines by flow injection analysis and immobilized enzymes.

Individual and simultaneous determination of ethanol and acetaldehyde in wines by flow injection analysis and immobilized enzymes.

Simultaneous Determination of Ethanol and Chloroform in Liquid Cough Preparations by Gas Chromatography

A gas chromatographic procedure using a styrene-divinylbenzene polymer as column-packing material is described. The use of this column allows for the complete separation and simultaneous determination of ethanol and chloroform contained in liquid cough preparations.