THE NEW YORK JOURNAL OF PHARMACY 



methylene blue as an invaluable adjunct 

 as an indicator, to the pharmacopoeial 

 process for the estimation of phenol with 

 Kopperschaar's solution. 



First, as an indicator it is cheap, stable, 

 sensitive, easily prepared and without 

 false side reactions. 



Second, it fills a gap in the above 

 process which is without delicate means 

 of detecting^ the end reaction. 



Third, the end reaction is sharp and 

 unmistakable, being unlike starch, by re- 

 acting in an opposite direction. 



Fourth, its strong affinity for iodine 

 allows it to readily react with iodine when 

 present in traces, when used as an indi- 

 cator. 



A COLORIMETRIC METHOD FOR 

 THE ESTIMATION OF PHENYL 

 SALICYLATE IN MIXTURES 

 WITH ACETPHENETIDIN, 



ACETANILIDE, ETC. 



By Ravmo.vd C. Flett, Ph. Ch.* 

 The usual assays of these preparations 

 are rather lengthy and cumbersome. 1 

 liave devised the following method, 

 which involves considerable less time, 

 and is in no less degree accurate. In 

 principle it depends on the intensity of 

 the violet coloration produced when a 

 salicylate is caused to react with a ferric 

 salt. And from the degree of intensity 

 of color produced by the sample, and by 

 matching it against a series of color 

 standards of Phenyl Salicylate of known 

 strength, the per cent, of Salol in the 

 sample may be calculated. As in every 

 means of estimation, by colorimetric 

 methods it is wanting in that various 

 operators differ in abilit\- to distinguish 

 between various shades of the same coloi 



*Mr. Flett is a candidati' for the degree of 

 Phar.D. 



x\s the reagents used are relativeh 

 small, weighing and measuring must be 

 carried out with the greatest accuracy; 

 as any error introduced multiplies itself, 

 many times, in the result. It is import- 

 ant, too, that the standards and the sam- 

 ple be prepared at the same time since 

 the colors are prone to change rapidly. 

 This method may be used also for the 

 estimation of any soluble salicylate. 



The Preparation of the Sample: Ex 

 tract a suitable quantity (accurately 

 weighed) of the sample with alcohol. 

 Filter, and wash with alcohol a sufficient 

 quantity, so that lo cc. of the liquid rep- 

 resents lOo milligrams of the sample. 



Phenyl Salicylate Standards: Dis- 

 solve I gram of pure (U. S. P.) Phenyl 

 Salicylate in a sufficient quantity of alco- 

 hol to measure exactly loo cc. (Each 

 cc. therefore represents lo mgms. of 

 Phenyl Salicylate.) 



Ferric Chloride Solution : Dilute 8 cc. 

 of Ferric Chloride Test Solution (U. S. 

 P.) with sufficient alcohol to measure 

 30 cc. 



Apparatus Required: i-i cc. pipette, 

 graduated in hundredths; 1-50 cc. bu- 

 rette, all glass; ii-io cc. Nessler tubes. 



DETERMINATION. 

 Part A. 

 From a burette, run into ten Nessler 

 tubes the standard Phenyl Salicylate So- 

 lution, so that each succeeding tube will 

 increase in amount one cc. That is, into 

 Xo. I Nessler, run i cc, into No. 2 

 Nessler, run 2cc., etc. Fill each to the 

 mark with alcohol. To the nth 

 Nessler add 10 cc. of the solution of the 

 sample previously prepared. Now to 

 each of the eleven tubes add i cc. of the 

 Ferric Chloride Solution. Match the col- 

 ors of the standards with that of the 



