32 



have been obtained. It has been our experience that the higher boiling fractions 

 extract coumarin as well as vanillin fully as well as the lower boiling fractions. 



Acetanilid: According to the official method this substance is to be looked for with 

 the vanillin only when it has been found with the coumarin. In one of these three 

 analyses of No. 4 reported all of the acetanilid was found with the vanillin. 



The figures given by Mr. Olsen on vanillin by extraction with petroleum were as 

 follows: No. 4, 0.080; No. 5, 0.054, from which it would appear that the extraction 

 wa< not prolonged sufficiently. 



Linwood A. Brown: Sample No. 5: The vanillin in this sample was somewhat 

 impure owing to coloring matter from which I was unable to purify it. . 



The results would seem to show that as far as vanillin is concerned the method is 

 >uti.< factory. The average on both vanillin and coumarin, however, indicates that 

 some of the latter is weighed as vanillin. The coumarin figures are uniformly low, as 

 are those for acetanilid, with one exception. One collaborator reports entire failure 

 of the Ritsert's test for acetanilid as given in the provisional methods, and suggests a 

 modification. 



WORK OP 1908. 



The work for 1908 was confined to the colorimetric method for the determination of 

 citral in lemon extracts. Fifteen sets of samples were sent out to collaborators who had 

 previously worked with the method, and reports have been received from twelve. 

 A< the method had been rather severely criticised by some of the members of the 

 American Extract Manufacturers' Association, they were invited to name two col- 

 laborators, and selected Mr. Edward Kremers, of the Wisconsin State College, and 

 Mr. Baer, of St. Louis. Samples were sent to both, and Mr. Kremero forwarded 

 his set to I. W. Brandel, of the University of Washington. The following description 

 of the method to be used was sent to each collaborator: 



DETERMINATION OF CITRAL IN LEMON EXTRACT. 



Reagents. 



Aldehyde-free alcohol. Allow alcohol (95 per cent by volume) containing 5 grams of 

 metaphenylene diamin hydrochlorid per liter to stand for twenty-four hours with 

 frequent shaking. (Note, nothing is gained by previous treatment with potassium 

 hydroxid.) Heat under a reflux cooler for at least eight hours, longer if possible 

 (often twenty-four hours are necessary), allow to stand over night and distil, rejecting 

 the first 10 and last 5 per cent which come over. Store in a dark, cool place in well- 

 filled bottles. 



Fucbsin solution. Dissolve one-half gram of fuchsin in 250 cc of water, add an 

 aqueous solution of SO 2 containing 16 grams of the gas and allow to stand until colorless, 

 make up to one liter with distilled water. This solution should stand twelve hours 

 before using and should be discarded after three days. 



Standard citral solution. One milligram of c. p. citral per cubic centimeter in 50 per 

 cent by volume aldehyde-free alcohol. 



Apparatus. 



A cooling bath. To be kept at from 14 C. to 16 C. The aldehyde-free alcohol, 

 fuchsin solutioiij and comparison tubes are to be kept in this bath. 



* '"lorimeter. Any form of colorimeter using a large volume of solution and adapted 

 to rapid manipulation may be used. 



The comparison may also be made in Nessler or Hehner tubes. 



Manipulation. 



Preliminary determination. Weigh in a stoppered weighing flask approximately 25 

 grams of extract, transfer to a 50 cc flask and make up to the mark at room temperature 

 with aldehyde-free alcohol. Measure at room temperature and transfer to a compari- 

 son tube 2 cc of this solution, add 25 cc of the aldehyde-free alcohol (previously cooled 



the bath) then 20 ccof the fuchsin solution (also cooled) and finally make up to the 



50 cc mark with more aldehyde-free alcohol. Mix thoroughly, stopper, and place in 



'ling bath for fifteen minutes. Prepare a standard for comparison at the same 



:ime and in the same manner using 2 cc of the standard citral solution. Remove and 



compare the colors developed. Calculate the amount of citral present and repeat 



