Ethanol fuel adulteration with methanol assessed by cyclic voltammetry and multivariate calibration (original) (raw)
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Substance Abuse Treatment, Prevention, and Policy
Background Methanol is highly toxic to human beings and naturally exists in some beverages. Having access to an easy and cheap method for its determination is of great importance to increase the safety of use of these beverages. Our main aim is to evaluate methanol concentration of some alcoholic beverages in Iran black market and compare it with the European and US standards. Also, we evaluated the efficacy of a newly designed and produced chemical kit in determining the risk of methanol toxicity by drinking of such samples compared to gas chromatography method. Methods Methanol content of suspected alcoholic beverages referred to forensic toxicology laboratory, Guilan province, Iran was measured using gas chromatography and a recently designed kit based on modified colorimetric chromotropic acid method. Results Of 1221 samples, 145 (11.9%) had no ethanol content, while in three samples (0.25%), methanol was high enough (700,000; 870,000; 920,000 mg/L) to cause severe methanol toxi...
Simultaneous Gas Chromatographic Quantitation Of Ethanol And Methanol From Beer
2020
Beer is the most widely consumed alcoholic beverage in South Korea. The ethanol content on the label of alcoholic beverages must be within 0.5% of the actual level and the methanol content limit in beer is 500 mg/L (0.05%) in Korea. Therefore, regular testing of ethanol and methanol is a legal requirement. In this research, we devised a GC-FID analytic method for determining ethanol and methanol levels in beer, based on the use of a DB-624 capillary column combined to the direct aliquot injection. C-18 Cartridge purification proved inappropriate for the analysis of ethanol and the use of ethyl acetate as an internal standard was found to overestimate methanol content. The devised method was successfully applied to thirteen kinds of domestic and imported beers in the market. The labelled ethanol percentages in beer samples were within 0.5% of measured levels, and methanol levels in all beer samples were under 500 mg/L (μg/mL). Therefore, all beer samples analyzed met legal requiremen...
Chromatographia, 2006
A new methodology was developed for analysis of aldehydes and ketones in fuel ethanol by high-performance liquid chromatography (HPLC) coupled to electrochemical detection. The electrochemical oxidation of 5-hydroxymethylfurfural, 2-furfuraldehyde, butyraldehyde, acetone and methyl ethyl ketone derivatized with 2,4-dinitrophenylhydrazine (DNPH) at glassy carbon electrode present a well defined wave at +0.94 V; +0.99 V; +1.29 V; +1.15 V and +1.18 V, respectively which are the basis for its determination on electrochemical detector. The carbonyl compounds derivatized were separated by a reverse-phase column under isocratic conditions with a mobile phase containing a binary mixture of methanol / LiClO4(aq) at a concentration of 1.0 × 10−3 mol L−1 (80:20 v/v) and a flow-rate of 1.1mL min−1 . The optimum potential for the electrochemical detection of aldehydes-DNPH and ketones-DNPH was +1.0 V vs. Ag/AgCl. The analytical curve of aldehydes-DNPH and ketones-DNPH presented linearity over the range 5.0 to 400.0 ng mL−1, with detection limits of 1.7 to 2.0 ng mL−1 and quantification limits from 5.0 to 6.2 ng mL−1, using injection volume of 20 μL. The proposed methodology was simple, low time-consuming (15 min/analysis) and presented analytical recovery higher than 95%.
Screening analysis to detect adulterations in Brazilian gasoline samples using distillation curves
Fuel, 2004
Data on evaporated fraction temperatures obtained from the distillation curves of Brazilian gasolines were employed to identify adulterated samples by applying the Soft Independent Modeling of Class Analogy (SIMCA) model. Since 1977, different quantities of ethanol have been added to the gasoline sold in Brazil. The ethanol concentration is established by Brazil's Petroleum Regulatory Agency. Ethanol and heavy solvent prices are lower than that for gasoline, so they are often added to the fuel for purpose of gasoline adulteration. Presence of these species in high or low concentration creates modifications in distillation curves. The SIMCA chemometrics method was selected due to its offering the possibility of sample classification into to the defined class. The training set for the SIMCA model consisted of 34 samples and test set consisted of 16 gasoline samples, eight of which were adulterated. Five principal components were necessary to explain 95% of the total variance. All test set samples were correctly classified while four samples of the training set, which were in conformity with legislation, were misclassified as contaminated by SIMCA.
Microchemical Journal, 2004
A novel strategy to evaluation of adulteration in alcoholic beverages based on the measurement of the Schlieren effect using an automated FIA system with photometric detection is proposed. The assay is based on the Schlieren effect produced when beverage samples are injected in a single-line FIA system that uses water as carrier stream and a light-emitting diode–phototransistor photometer controlled by microcomputer as detector. The flow system presents limited mixing conditions which make possible to create gradients of refractive index (Schlieren effect) in the injected sample zone. These gradients are reproducible, characteristic of each alcoholic beverage and undergo specific modifications when adulterations with water or ethanol are imposed. Schlieren effect data of brandies, cachaças, rums, whiskies and vodkas were treated by SIMCA to elaborate class models applied in the evaluation of alcoholic beverages adulteration. Samples of the original matrix of each sort of beverages were adulterated in laboratory by adding water, methanol and ethanol in levels of 5% and 10% (v/v). These samples were used as test set to validate SIMCA class models. The verification of authenticity using Schlieren effect measurements presented good results making possible to identify 100% of the beverages samples adulterated in laboratory and 93% of the actual adulterated alcoholic beverages with confidence levels of 95%. As principal advantage, the automated system does not use reagents to carry out the analysis.