V O L U M E 2 0 , NO. 1 2 , D E C E M B E R 1948 (33)
Bhapiro, A., Lener. H.. and Rosen, E., Proc. SOC.Ezptl. Biol.
.Wed., 32, 1300 (1935). (34) Skinkle, J. H., and Platt, W. W., -4m. Dyesti(j’Reptr., 31, 537 (1942).
Smith, E. F., “Electro Analysis,” p . 136, Philadelphia, Blakiston Co., 1907. (36) Steams, E. I., Am. Dyestuj’ R e p t r . , 33, 1 . 16 (1944). (37) Stovall, m‘. D., Foote, M . . and Nichols, K. S., Am. J . CZin.
1191 Taub, -4.. J . Am. Pharm. Assoc., 16, 116 (1927). Welcher, F., “Chemical Solutions,” New York, D. Van Nostrand Co.. 1942. (40) Windisch, W., Dietrich. W., and Kolbach, P., Chemie et Indus-
(38) (39)
h i e , 8, 1099 (1922).
(35)
Path., 3, 299 (1933).
RECEIVED March 97, 1948. From a thesis presented by Blanche L. Ingram the Graduate School of Cornel1 Cniversity in partial fulfillment d the requiremencs for the degree of master of science. GO
Determination of Phenol and Structurally Related Compounds by the Gibbs Method AI. R . ETTINGEK AND C. C. KUCHHOIT Sanitary Engineering Division, U . S. Public Health Sercice, Cincinnati, Ohio h detailed study of some of the factors affecting the analytical use of the reaction of 2,6-dibromoquinone chloroimide with some phenolic materials is presented. Factors that affect the amount and charac- s teristics of the colors produced include the time allowed for reaction, the temperature, the pH, and the 2,6-dibromoquinone chloroimide used. The characteristics of the color produced and of the reaction vary with different phenolic materials. If
P
RELI,\IISXRY to the study of the persistence of phenolic materials in surface water, methods for the determination of phenol and certain closely allied materials have been re-examined. The techniques finally selected differ from those currently used and offer definite advantages n-here quantitative results are required. For the investigation of problems involving phenolic materials in their relation to water Supplies, analytical methods should be sensitive to a few parts per billion of phenol or the cresols. The precision of the method should be as high as can be obtained without sacrifice of sensitivity. Minimal manipulation is desirable. Results should be available as quickly as possible to permit operational adjustments in \rater plants, etc. The fundamental studies of Gibbs (6, 7 ) are responsible for the development and underst,andiny of the use of 2,6-dibronioquinone chloroimide for the determination of phenolic materials. The phenolic material is made to react with Gibbs reagent in a buffered alkaline solut,ion to produce dyes belonging to the indigo family. The dyes are generally osidation-reduction indicators (8). They are likely to be blue, green, or purple in the alkalinc form; the acid form is usually red or orange. After being produced by the Ckibbs reaction, they may be extracted with isobutyl alcohol, n-butyl alcohol, or amyl alcohol ( I O ) to give the dye in the alkaline form, or ethyl acetate \rill extract the dye in the acid form. There is a shift in the light-absorption characteristics when the dve is extracted n-ith one of the alcohols that extract the alkaline form. Although Gibbs did not give a specific procedure in the basic work ( 6 ) ,he carried out his reactions in buffered solutions and followed the light transmittance of the solutions a t the wave length of maximum absorption until maximum color was developed. Gibbs reported further that pH and temperature affected t,he rate of color formation, and close study of Gibbs’s papers leads to the belief that the stability of the color formed is also affected by the same variables. pH values of 9.1 t o 9.5 were recommended, and the sensitivity was described as being such that 50 parts per billion could be detected. The test was quickly adapted to use in water plant practice by Baylis ( 3 ) and Theriault ( I S ) , both of whom recommended distillation from acid solution, treatment of
the reaction products are extracted from aqueous solution with n-butyl alcohol, the light-adsorption characteristics of the extract differ from those of the aqueous solution of the dye. The details of a procedure designed to take due account of the variables involved are presented here, and a further accelerated procedure which gives results more quickly, although with some sacrifice of precision and sensitivitj , is outlined. tile tiistillate with GiIi1)s reagent undei, conditions of controlled p11, and comparison with standards set up concurrently, and of the same pH as the sample. Baylis used pH values of 9.6 to 10.0, while Theriault reconinieiided a pH of 9.4. In either procedure, in order to secure the desired sensitivity it is necessary to effect some concentration. Baylis used fractional distillation under closely controlled conditions, n-hile Theriault recommentled concentration by alkaline evaporation. FractiouaI distillatioil ii riot a very satisfactory procedure for i,outiiie Ialioi~atory w.~rl
