Correct quantitative determination of ethanol and volatile compounds in alcohol products

Determination of the volume content of ethanol in the alcohol products in practice is usually determined by pycnometry, electronic densimetry, or densimetry using a hydrostatic balance in accordance with Commission Regulation No 2870/2000. However, these methods determine directly only density of the tested liquid sample and does not take into account the effects of other volatile components such as aldehydes, esters and higher alcohols. So they are appropriate only for binary water-ethanol solutions in accordance with international table adopted by the International Legal Metrology Organization in its Recommendation No 22. Availability notable concentrations of the higher alcohols and ethers in different alcohol-based products, e. g. in whisky, cognac, brandy, wine as well as in waste alcohol and alcohol beverage production, leads to the significant contribution of these compounds in the value of the density of tested alcohol-containing sample. As a result, determination of the volume of ethanol content for such alcohol products in gives the value of the strength, which may significantly differ from the true one. Using incorrectly calculated volume content of ethyl alcohol leads to incorrect results determining the quantities of volatile compounds in the alcohol-containing products, expressed in milligrams per liter of absolute alcohol. We propose experimental results of the method of correct determination of ethanol and other volatile compounds content in waste products of alcohol and alcoholic beverage industry by gas chromatography. Calculations are based on the measured value of sample density and volatile compound concentrations expressed in mg per liter of absolute alcohol [JAFC 61(2013)2950]. The method can be easily incorporated into daily practice of analytical and control laboratories with no additional material, financial or time costs.Comment: 4 pages, 2 figures, submitted to Proc. of the Wine Active Compounds (WAC) 2014 international conference (Beaune, France, March 26-28, 2014

High Sensitivity Mass Spectrometric Quantification of Serum Growth Hormone by Amphiphilic Peptide Conjugation

Amphiphilic peptide conjugation affords a significant increase in sensitivity with protein quantification by electrospray-ionization mass spectrometry. This has been demonstrated here for human growth hormone in serum using N-(3-iodopropyl)-N,N,N-dimethyloctylammonium iodide (IPDOA-iodide) as derivatizing reagent. The signal enhancement achieved in comparison to the method without derivatization enables extension of the applicable concentration range down to the very low concentrations as encountered with clinical glucose suppression tests for patients with acromegaly. The method has been validated using a set of serum samples spiked with known amounts of recombinant 22 kDa growth hormone in the range of 0.48 to 7.65 \mug/L. The coefficient of variation (CV) calculated, based on the deviation of results from the expected concentrations, was 3.5% and the limit of quantification (LoQ) was determined as 0.4 \mug/L. The potential of the method as a tool in clinical practice has been demonstrated with patient samples of about 1 \mug/L

Kinetics of diffusion interaction in the Ti-NiCr system layered composites

The results of investigation of the diffusion interaction kinetics at the boundary of explosion welded Ti-NiCr system compositions during heat treatment are presented. The structure, chemical and phase composition of the formed diffusion zones are also studied. It is shown that the layered diffusion zone is formed at a temperature below the eutectoid transformation. Diffusion zone consists of solid solutions based on Ti2Ni, TiNi, and TiNi3 intermetallic compounds, as well as chromium-based solid solution inclusions along the boundary with the NiCr alloy. An increase in temperature above the eutectoid transformation leads to an intensification of the growth of the diffusion zone and the diffusion of nickel into the titanium alloy with the formation of a eutectoid structure in it. The use of alloyed titanium alloys instead of commercially pure titanium does not affect the phase composition of the formed diffusion zones, but slows down the diffusion processes

Microstructure Evolution and Growth of Interfacial Intermetallic Compounds in NiCr/Ti Alloy Laminated Composite after Explosive Welding and Heat Treatment

The paper considers the issues of interaction of the molten metal at the interface of explosively welded NiCr/titanium alloy laminated composites with the reaction zone formed during heat treatment, as well as the features of its destruction after welding. It was established that the molten metal is a heterogeneous mixture based on Ni(Cr,Ti) and Ti(Ni,Al) solid solutions and NiTi and Ni3Ti intermetallic compounds. The estimated existence time of molten metal areas in the liquid state was ~10−8–10−11 s. The obtained values are comparable with the time of the unloading wave arrival at the contact surface, which is the reason for the presence of fracture areas in the form of detachments on the fracture surface. Continuous nanometer-size interlayers with an amorphous structure, due to the ultra-high cooling rate of the liquid melt, induce viscous destruction of the interface. Heat treatment at temperatures of 700 and 850 °C led to the formation of a layered reaction zone at the NiCr/Ti boundary, consisting of interlayers of solid solutions based on Ti2Ni, TiNi, and TiNi3 intermetallic compounds, as well as inclusions of a Cr(Ti) solid solution. The diffusion flow gradient was predominantly directed into the titanium alloy

Development of reference materials of volatile compounds in alcohol production

Proceedings of the 1-st International Scientific Conference "Reference Materials in Measurement and Technology"(September 10-14, 2013, Ekaterinburg, Russia). P.90-9

Development of reference materials of volatile compounds in alcohol production

Presentation and report at the 1-st International Scientific Conference "Reference Materials in Measurement and Technology"(September 10-14, 2013, Ekaterinburg, Russia)