Ethanol, determination

Fig. 1. Fraction of non-hydrogenbonded ( free ) OH-groups in water, methanol and ethanol determined by IR-spectroscopy. xF is the fraction of hole defects for water71...

After refluxing, disconnect the trapping tube, and transfer the yellow solution into a 25-mL volumetric flask. Rinse the mbe with ethanol, and adjust the solution to volume with ethanol. Measure the absorbance of the solution at 435 nm against a blank prepared by diluting 15 mL of color reagent to 25 mL with ethanol. Determine the carbon disulflde content from a calibration curve obtained by plotting carbon disulfide concentrations of different standard solutions on the abscissa versus the absorbance on the ordinate. 

An electron transfer type of enzyme sensor was thus fabricated by a electrochemical process. Although no appreciable leakage of ADH and MB from the membrane matrix was detected, NAD leaked slightly. To prevent this leakage, the ADH-MB-NAD/polypyrrole electrode was coated with Nation. A calibration curve is presented in Fig.25 for ethanol determination in an aquous solution with the enzyme sensor. Ethanol is selectively and sensitively determined in the concentration range from 0.1 nM to 10 mM. 

Figure 3.11 — (A) Immobilized peroxidase sensor. Glass-immobilized peroxidase is packed in the flow-cell shown. The plastic support plate fits the top surface of the photomultiplier chamber of the immunometer so as to support the vertically held flow-cell in front of the photomultiplier itself. (B) Flow system for hydrogen peroxide/ethanol determinations. For ethanol determinations, the immobilized alcohol oxidase column is inserted immediately after the injection valve (shown by the arrows). Luminol (62 /zM) and 4-iodophenoI (0.4 M) are dissolved in 200 mM borate buffer (pH 8.9) and pumped at a flow-rate of 0.8 mL/min. Phosphate buffer (10 mM, pH 7.0) is pumped at 1.6 ml/min. (Reproduced from [78] with permission of Elsevier Science Publishers).

The British Pharmacopoeia has adopted the assay of chlorpromazine in acetone, using a non-aqueous titration with perchloric acid and methyl orange as the indicator [4], According to the described procedure, each mL of 0.1 M perchloric acid is equivalent to 0.03189 g of drug substance. For chlorpromazine hydrochloride, the BP has described its titration with NaOH in a 1 10 solution of 0.01 M HCl / ethanol. Determining the end point potentiometrically, each mL of 0.1 M sodium hydroxide is equivalent to 0.03558 g of substance. 

Ethanol Determination by Estimation of Its Hydroxyl Group, Using Various Esterification Procedures... 

In Ref 3, under "Ethanol Determination by Estimation of Its Hydroxyl Groups Using Various Esterification Procedures are described methods which are applicable to analysis of glycols... 

Ethanol Determination in Solvents Used in Manufacture of Smokeless Propellants and also tinder Ethanol... 

Ethanol. The accurate, reasonably rapid, and relatively inexpensive ethanol determination is the most important analytical procedure for the winery analyst. Not only is it required for legal reasons but also for winery control and research investigations. 

L. Rotariu, C. Bala and V. Magearu, New potentiometric microbial biosensor for ethanol determination in alcoholic beverages, Anal. Chim. Acta, 513(1) (2004) 119-123. 

Fig. 2 Calibration curve in Round No. 73. Calibration data are shown by dots, the calibration curve obtained by the ordinary least squares technique, by the solid regression line 5 the limits of the regression corridor by dotted lines 4 and 6 the result of the ethanol determination in the sample by the dotted lines 1 and 8 the calibration curve for 3-times increased uncertainty of the certified value by the solid regression line 3, and the limits of its corridor by thin lines 2 and 7...

This article presents the design and implementation of a software sensor for the continuous determination of substrate concentration based on a simple model of a fed-batch fermentation process and the available signals of two other sensors—one for on-line biomass determination (7) and the other for on-line ethanol determination (8)—developed in previous works. The software sensor proposed provides a continuous signal that can be used in a control loop to manipulate the substrate feed flow in order to maintain almost constant substrate concentration and obtain an excellent level of productivity and yield during all of the process, as shown in experimental control strategy studies in previous works (9). 

The water content of the ethanol, determined by Karl Fischer analysis, is 0.02-0.10%. 

Ethanol is frequently taken at the same time as other drugs and can intensify the action of depressant drugs. A blood-ethanol determination assists in distinguishing this from normal alcoholic intoxication it is also useful in the clinical assessment of unconscious patients admitted with head injuries and smelling of drink. Children are particularly at risk from hypoglycaemia which may follow ingest-ion of alcohol. 

Traditional methods of analysis for determination of principal organic acids, glycerol and sugars in wine are based on enzymatic or colorimetric reactions ethanol is determined by distillation of wine and density measurement of the distillate. In Table 1.2, data of organic acids, glycerol, glucose, fructose and ethanol determined by HPFC are reported as a percentage of results obtained by the traditional methods. 

The area around the intended puncture site should be cleaned with a prepackaged alcohol swab or with a gauze pad saturated with 70% isopropanol. Cleaning of the puncture site should be done with a circular motion and from the site outward. The skin should be allowed to dry in the air. No alcohol should remain on the skin, because traces may cause hemolysis and invalidate test results. When specimens are to be collected for ethanol determinations, the skin should be cleaned with a benzalkonium chloride solution (Zephiran Chloride solution, 1 750) that is free of alcohol. Povidone-iodine should be avoided as a cleaning agent because it may interfere with several chemistry procedures. Once the skin has been cleaned, it should not be touched until after the venipuncture has been completed. 

Whitehead et al.5 report that in aqueous 66% N,N-dimethylformamide, 3,4-dihydro-3-substituted-7-sulfamoyl-1,2,4-benzothiadiazine 1,1-dioxides are characterized by two pKa s of 11.0-11.4 and 13,0-13.3. Novello and Sprague12 reported pKa s of 9.1 and 10.5 for cyclothiazide. In the latter case the pKa represents the pH at half neutralization in 30% aqueous ethanol determined potentiometrically. 

An organic chemistry professor performed a flash distillation experiment in a laboratory for his students. A 10-kgmol/h liquid feed mixture consisted of 20 mol % ethanol and 80 mol % water at 1 atm. While the professor was able to determine that 30 mol % of the feed vaporized at 70°F, he lacked the necessary equipment to measure the liquid and vapor compositions of the more volatile component, ethanol. Determine the liquid and vapor compositions, as well as the percent ethanol recovery from the flash. Equilibrium data for the ethanol-water system at 1 atm are provided in MTO.l. 

The relative contribution of ethanol in cases of coma, especially where other drugs and/or head injury arc present, may be difficult to distinguish. Blood ethanol determinations arc the best guide. Where these are not available, plasma osmolality measurement and calculation of the osmolal gap may help. 

The data below give the density of ethanol-water solutions as a function of the weight fraction of ethanol. Determine the volume of solution that is formed when 0.1 ma of ethanol is mixed with 0.1 ma of water and report the excess volume in ma/mol. 

D8. For Problem 4.D7c for separation of acetone from ethanol, determine a. How many stages are required at total reflux ... 

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