No detailed procedures have previously been published for the rapid, precise, and convenient determination of micro quantities of copper. Flame spectrophotometric studies at the copper line (324.7 µ) showed that the radiant power of copper was greatly enhanced by aspirating from an 80% methanol solvent. Interference studies indicated that nitric acid could be tolerated in appreciable quantities. Most cations show considerable radiation interference; however, the increase in the radiant power of copper caused by the addition of nine cations to standard copper solutions was determinable at a wave length of 325.1 mg. Inasmuch as no preliminary separations are necessary, the method is adaptable to routine determinations.The results are as accurate as conventional microchemical procedures.ALTHOUGH there are many publications on the determina-jTX. tion of alkali and alkaline earth metals by flame photometry, relatively few investigators have reported on the flame photometric determination of copper (1,3,(9)(10)(11)(15)(16)(17). Of these, only Dean (3) and Jordan ( 11) have described methods in detail. Dean (S) worked with nonferrous alloys containing copper in the range from 0.3 to 2.5%, and Jordan (11) analyzed for small amounts of copper in a hydrochloric acid extract of gasoline.Work by Dean and Lady (5,13) indicates that copper can be determined in micro quantities by flame photometry after a preliminary extraction of the copper as the salicylaldoxime with either chloroform or amyl acetate. Table I. Radiant Power of 4 per Ml. of Copper with Various Alcohols as Solvent Radiant Power, Scale Divisions0 Alcohol % Cu + ROH ROH Net Ci Methanol 95 54.2

A simple, rapid, and accurate method is described for determining the concentration of alcohol in ethanol solutions using a density meter. With this instrument, the U-tube is suctionfilled with 0.7 mL sample, and the results are displayed on a digital read-out in specific gravity units. These values are converted by tables to per cent ethanol or proof. For samples under 40° proof, the instrument is standardized on air and water. When testing samples between 40 and 193° proof, the instrument is standardized on air and an ethanol standard having a proof within ±30° of the sample tested. Thus, large corrections for the nonlinearity of the plot of the specific gravity of ethanol vs. proof are avoided. An equation is presented that corrects for this non-linearity, and the result is obtained in per cent ethanol rather than specific gravity. Proof results obtained with this instrument are in good agreement with the values obtained by a pycnometer and/or refractometer for 1–190° proof ethanol-water solutions, vodkas, whiskeys, brandies, and liqueurs.

No abstract

A rapid and accurate method is described for determining proof of alcoholic products containing dissolved solids. Samples are distilled in a Jaulmes distillation unit and alcohol concentration is determined by a proof hydrometer. Shortened analysis time is due to the rapid distillation rate afforded by the Jaulmes unit. Recovery data and comparisons with results by a modified AOAC method are presented for 18 commercial alcoholic beverages. Results obtained, using the 2 methods, were in good agreement; a maximum difference in results of 0.4° proof was found for 2 of the 18 samples tested.

A method for measuring color intensity of whisky was developed to replace the present AOAC method, which has become obsolete. The new method was collaboratively studied by 20 persons. Color intensity of whisky was measured as absorbance by a spectrophotometer, using a 1 cm cell, a bandwidth ≤10 nm, and a wavelength of 525 nm. Water was used as reference. Collaborator results appear acceptable for whisky samples that vary in color intensity from 29 to 374 CIU (absorbance X 1000 = Color Intensity Units (CIU)). The maximum standard deviation and coefficient of variation were 5.8 CIU and 6.68%, respectively. The method has been adopted official first action.