ANALYTICAL EDITION
January 15, 1942
TABLE11. ANALYSISOF ESSENTIAL OILS Authors' Method Average deviation 1.1 0.3
% of alcohol
Oils Cedar oil 1 Cedar oil 2
constituent 13.9 6.7
-. _ ~.- " . N'WSti"P
Lavender oil Sandalwood Rosemary Cinnamon Citronella Cloves
% total alcohol % free
...
values 65.1 9.8
0.5 0.6
23:6 72.6
0.4 1.4
=
...
Brignall's Method Average deviation 0.8 0.8
% of alcohol oonstituent 12.7 8.7 16.6
63.5 10.1 13.3 35.0 73.9
...
0.7
0.1 1.3 1.1 0.1
( molecular weight of ester ) % ester molecular weight of alcohol
-t
Analyse- of other eqsential oils containing various alcohols werc attempted with this procedure. The results are given in Table 11.
55
As indicated, the results in most cases were not very satiefactory, probably because of the unsaturated nature of the alcohols in question, which apparently absorb the dry hydrogen chloride. During titration this hydrogen chloride is slowly released, giving rise to erroneous results. For this reason the authors do not recommend the procedure ab described for determination of free alcohols in oils other tlxtn peppermint,
Literature Cited (1) Brignall, T. W., IND. ENO.CHEM.,ANAL.ED.,13, 166 (1941) (2) Christensen, B E., Pennington, L., and Dimick, P. K., Ibid., 13, 821 (1941). (3) Linderstrgm-Lang, K., and Holter, H., Compt.-rend. trav. lab. Carlsberg, 19, S o . 4 (1931); Z . physiol. Chem., 201, 9 (1931). (4) Smith, D. >I., and Bryant, W.M .D., J . Am. Chem. SOC, 57, 61-5 (1935). PCBLIEHED with the approval of the Monographs Publications Committee Oregon State College. Research Paper No. 5 2 , School of Science, Department of Chemistry.
Acidimetric Orthophosphoric Acid Assay JOSEPH A. CALAMARI AND ROBERT HUBATA New York General Depot, Medical Section, New York, N. Y.
K
OLTHOFF (1) has shown that the presence of sodium chloride in the alkalimetric titration of orthophosphoric acid lowers the p H of both the first and second end points and that the acid may be accurately titrated as a monobasic a n d dibasic acid by using methyl yellow and phenolphthalein, respectively, as indicators for the two end points. I n the titration to the phenolphthalein end point, the solution is half saturated with sodium chloride to suppress the ionization of the dibasic salt, while the methyl yellow titration is conducted without the addition of sodium chloride. Similar procedures are used in the U. S. Pharmacopoeia
