NMR ANALYSIS OF COSMETIC INGREDIENTS 513 alcohol and water. The triplet at 1.0 ppm and the quartet at 3.45 ppm repre- sent the methyl and methylene groups, respectively, of ethyl alcohol. The hy- droxyl hydrogen rapidly exchanges with the water hydrogens producing a single peak which shifts with concentration. In this spectrum the broad peak appears at 4.55 ppm. Again, by using, the methyl group as a reference, we can calculate the area per proton by dividing the triplet area by three. The area produced by the OH of ethanol, which is equal to the area per proton, can then be subtracted from the OH-H2 peak, leaving the area of the 9, water hydrogens. This area is then divided by two, producing the area for each water hydrogen. The following equation is then used to calculate the alcohol-water ratio: Alcohol = (area of OH peak) (molecular wt of ethanol) Water = (area per H20 hydrogen) (molecular wt of H_oO) (8) In evaluating uncomplicated spectra, accuracy and precision of the results are largely dependent upon two variables, namely, the accuracy of the inte- grator and the ability of the operator to determine the various inflections re- lat ng to each peak in the spectrum. Instrumental conditions are set so that maximum integrated inflection points are obtained and the operator's interpretation of where the peak be- gins (inflection from the baseline) and where the peak ends is thus mini- mized. The reproducibility of the integrator is generally -+5% (i.e., areas ob- tained on the same sample run consecutively). The integrator reproducibility became a problem in our analysis for ester value. The factor of 58.1 included in the calculation causes minimal errors in the integration to produce unacceptable deviations in the final values. In order to correct this deviation, we are now undertaking raw data studies preliminary to programming an 1800 IBM Computer for NMR peak area analysis. Table I Comparison of NMR rs. Wet Analysis Iodine Value Compound Oleyl alcohol Specs. Wet NMR (3 runs) _ 89.0-- 93.0 94.6 94.0 ñ 0.2 Sesame oil Refined avocado oil Isodecyl oleate Acetylareal ethoxylated }anolin alcohol Oleyl alcohol (ETO) Oleyl alcohol (ETO) 103,0 - 116.0 105.0 105,6 _+_ 1.1 65.0 - 95.0 83.0 83.4 -+ 0.8 54.0- 62.0 57.8 57.6 ñ 1.3 18.0 - 22.0 ... 21.7 -+- 0.4 30.0- 40.0 33.2 34.1 _+__ 1.2 19.0- 25.0 21.0 21.6 -+- 1.4

514 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table II Comparison of NMR rs. Wet Analysis Ethoxyl',ation (Moles) Compound Suppliers Spec. NMR (3 runs) Oleyl alcohol (ETO) 10 --10 _•0•- - Acetylated ethoxylated lanolin alcohol 10 9.7 ñ 0.9 Polyoxyethylene (2) stearyl ether 2 2.2 _4- 0.3 Polyoxyethylene (2) cetyl ether 2 2.3 _ 0.1 Oleyl alcohol (ETO) 20 19.8 ñ 0.6 In the analysis for iodine value, concurrent wet chemistry tests were car- ried out to see the comparisons of NMR results versus the more classical methods. Table I lists these results. Table II lists the values of moles of ethoxylation compared to the approved supplier's specification. SU•vI•X•ARY. The NMR spectrophotometer is no longer solely the qualitative tool of a research chemist. The cost is not prohibitive and its data can be applied to quality control work to replace time consuming wet analysis tests such as ester value, iodine value, average moles of ethoxylation, and alcohol-water ratios. ACKNOWLEDG3elENT The authors would like to express their appreciation to the Communica- tion Skills Corp. for the use of their demonstrati.on figures. ( Received January 31, 1974) I•EFERENCES (1) Flockhart, B. O., and Pink, R. C., Applications of nuclear and electron magnetic resonance in analytical chemistry, Talanta, 12, 529-57 (1965). (2) Parfitt, R. T., Nuclear magnetic resonance spectroscopy, Pharm. J., 203, 300-3 (1969).