Final report of key comparison CCQM-K4 (ethanol in air)

2013

From within AFRIMETS, the Regional Metrology Organization (RMO) for Africa, the RMO Key Comparison AFRIMETS.QM-K27 was coordinated by the National Metrology Institute of South Africa (NMISA) in 2011. Ten Metrology Institutes participated, comprising three AFRIMETS, two APMP, four EURAMET and one SIM participant. Participants were required to determine the forensic level concentration of two aqueous ethanol solutions that were gravimetrically prepared by the NMISA. Concentrations were expected to lie in the range of 0.1 mg/g to 5.0 mg/g. The accurate determination of ethanol content in aqueous medium is critical for regulatory forensic and trade purposes. The CCQM Organic Analysis Working Group has carried out several key comparisons (CCQM-K27 series) on the determination of ethanol in wine and aqueous matrices. Developing NMIs now had the opportunity to link to the earlier CCQM-K27 studies through the AFRIMETS.QM-K27 study. Gas chromatography coupled to flame ionisation or mass spec...

Journal of the Institute of Brewing, 2016

Ethanol production in the United States approached 15 billion gal/year in 2015. Only about 2.5% of this was food-grade alcohol, but this represents a higher-value product than fuels or other uses. The ethanol production process includes corn milling, cooking, saccharification, fermentation, and separation by distillation. Volatile byproducts are produced during the fermentation of starch. These include other alcohols, aldehydes, ketones, fatty acids and esters. Food-grade ethanol is generally produced by wet milling, where starch and sugars are separated from the other corn components, resulting in much smaller concentrations of the impurities than are obtained from fermentation of dry-milled corn, where cyclic and heterocyclic compounds are produced from lignin in the corn hull. Some of these volatile byproducts are likely to show up in the distillate and these fermentation byproducts in ethanol could cause unpleasant flavours and affect human health if used for human consumption. There is some interest in improving ethanol quality, since human consumption represents a higher value. Advanced purification techniques, such as ozone oxidation, currently used for drinking water and municipal wastewater treatment, offer possibilities for adaptation in ethanol quality improvement. The development of analytical techniques has enabled the detection of low-concentration compounds and simple quality assurance of food-grade alcohol. This review includes the most recent ethanol production methods, potential ethanol purification techniques and analytical techniques. Application of such techniques would aid in the development of simplified alcohol production.

Accreditation and Quality Assurance, 2008

This study simulated the transport and storage conditions of ethanol in water certified reference material (CRM) produced by the Chemical Metrology Division of Inmetro -DQUIM with the purpose to estimate the measurement uncertainty related to stability. The short-term stability study was performed on five different concentrations in terms of g ethanol/100g solution (%) of the ethanol in water CRM: 0.0509%, 0.0890%, 0.1145%, 0.3820% and 0.4960%, at the temperatures of 4 ºC and 60 ºC. On the other hand, the longterm stability study was developed on four different concentrations: 0.0509%, 0.0890%, 0.1145% and 0.4960%. In this paper will be shown data from the long-term stability study concerning 20 weeks.

This standard is issued under the fixed designation D 3695; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

2000

This study simulated the transport and storage conditions of ethanol in water certified reference material (CRM) produced by the Chemical Metrology Division of Inmetro-DQUIM with the purpose to estimate the measurement uncertainty related to stability. The short-term stability study was performed on five different concentrations in terms of g ethanol/100g solution (%) of the ethanol in water CRM: 0.0509%, 0.0890%, 0.1145%, 0.3820% and 0.4960%, at the temperatures of 4 ºC and 60 ºC. On the other hand, the longterm stability study was developed on four different concentrations: 0.0509%, 0.0890%, 0.1145% and 0.4960%. In this paper will be shown data from the long-term stability study concerning 20 weeks. The method used complies with ISO GUIDE 35, BCR-Guideline for Feasibility Studies and ISO GUIDE 34. According to the statistical parameters used in both studies the stability of the ethanol in water CRM was confirmed for all concentrations studied.

This publication was reproduced from the best available camera-ready copy submitted by the subcontractor and received no editorial review at NREL.

2006

This work presents the determination of the evaporation factor of ethanol and the contribution of this source of uncertainty in the process of certifying a reference material composed of solutions of ethanol in water. For this purpose, an experiment involving three technicians was carried out, where each one of them performed measurements during two days. Since the certification process is based on the gravimetric preparation of solutions by two different methodologies: individual and batch, the evaporation experiments involved measurements that complied both methodologies.

Energy & …, 2009

The existence of organic and inorganic contaminants present in both fossil and biomass fuels and the fact that they can provide undesirable effects (environmental problems, corrosion processes, lead to storage instability, and others) implies a rigorous quality control of these fuels, although these contaminants make up a small part of the final fuel composition. Considering the rising importance of fuel ethanol in the worldwide panorama, this review aims at reporting the use of successful alternative analytical methods in the monitoring of organic and inorganic contaminants at trace levels, used to determine and to quantify these substances in fuel ethanol and also presenting all official norms for quality control of fuel ethanol employed by ABNT (Brazilian Association of Technical Norms), ASTM (American Society for Testing and Materials), and ECS (European Committee for Standardization).

Journal of AOAC International, 2018

EnzytecTMLiquid Ethanol is an enzymatic test for the determination of ethanol in kombucha, juices, and alcohol-free beer. The kit contains two components in a ready-to-use format. Quantification is based on the catalytic activity of alcohol dehydrogenase, which oxidizes ethanol to acetaldehyde and converts NAD+ to NADH. Measurement is performed in 3 mL cuvettes at 340 nm within 20 min. Samples with alcohol contents around 0.5% alcohol by volume need to be diluted 1:20 or 1:50 with water before measurement. Acetaldehyde interferes at concentrations higher than 3000 mg/L, whereas sulfite interferes at concentrations higher than 300 mg/L. The linear measurement range is from 0.03 up to 0.5 g/L ethanol, whereas LOD and LOQ are 1.9 and 3.3 mg/L ethanol, respectively. Kombucha with concentrations between 2.85 and 5.82 g/L showed relative repeatability standard deviation around 1%, whereas juices were below 2%. Results from a reproducibility experiment revealed that at a concentration of 0...