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 was 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.

3

The result would seem to show that as far as vanillin is concerned the method is satisfactory. 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 OF 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. As the method had been rather severely criticised by some of the members of the American Extract Manufacturers' Association, they were invited to name two collaborators, and selected Mr. Edward Kremers, of the Wisconsin State College, and Mr. Baer, of St. Louis. Samples were sent to both, and Mr. Kremers 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 wellfilled bottles.

Fuchsin solution.-Dissolve one-half gram of fuchsin in 250 cc of water, add an aqueous solution of SO, 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 solution, and comparison tubes are to be kept in this bath.

Colorimeter. 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 comparison tube 2 cc of this solution, add 25 cc of the aldehyde-free alcohol (previously cooled in the bath) then 20 cc of the fuchsin solution (also cooled) and finally make up to the 50 ce mark with more aldehyde-free alcohol. Mix thoroughly, stopper, and place in the cooling bath for fifteen minutes. Prepare a standard for comparison at the same time 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

the determination using a quantity sufficient to give the sample approximately the strength of the standard. From this result calculate the amount of citral in the sample. If the comparisons are made in Nessler tubes, standards containing 1, 1.5, 2, 2.5, 3, 3.5, and 4 mg should be prepared and the trial comparison made against these, the final comparison being made with standards between 1.5 and 2.5 mg varying but one-fourth of a milligram.

The following points are to be especially noted:

The aldehyde-free alcohol (25 cc) on standing for 20 minutes in the cooling bath with the fuchsin solution (20 cc) should develop only a faint pink coloration. If a stronger color is developed, treat again with metaphenylene-diamin hydrochlorid.

It is absolutely essential to keep the reagents and comparison tubes at the required temperature. Comparisons should be made within one minute after removing the tubes from the bath. Where the comparisons are made in the bath (this is possible only where the bath is glass) the standards should be discarded within twenty-five minutes after adding the fuchsin solution. Give samples and standards identical treatment.

Note on samples colored with turmeric whether or not the color interferes with the comparisons. On samples 2 and 3, after making determinations on the samples sent, repeat them, removing the colors as follows: After weighing the sample to be used for analysis in a glass stoppered weighing bottle, add a drop of concentrated hydrochloric acid and a small piece of fat-free woolen cloth, stopper and allow to stand over night. Remove the cloth washing with aldehyde-free alcohol and determine the citral in the colorless solution as usual. Repeat the above comparison heating the acidified sample and woolen cloth under a reflux cooler for a few minutes, cool, remove the cloth and determine the citral as usual.

The samples sent were as follows:

No. 1. A lemon extract containing 3,008 grams of 95 per cent alcohol and 192 grams lemon oil, the whole colored with turmeric.

No. 2. A terpeneless extract of lemon strengthened with citral; 300 grams lemon oil dissolved in 1,796 grams of 95 per cent alcohol; 2,070 grams of water were added and after standing over night the precipitated oil was removed and 3.76 grams of citral added. The whole colored with Naphthol Yellow S.

No. 3. A solution of citral in dilute alcohol (50 per cent volume) containing 3,000 grams alcohol, 3.6 grams c. p. citral making the actual percentage of citral 0.12 per cent. The whole colored with Naphthol Yellow S.

No. 4. A solution of citral in dilute alcohol (50 per cent by volume) containing 3,500 grams alcohol and 2.12 grams c. p. citral making the actual percentage of the latter 0.061. The whole colored with turmeric.

The results reported are given in the following table:

Collaborative work on determining citral in lemon extracts, 1908.

COMMENTS OF ANALYSTS.

R. W. Hilts: The methods submitted for this work were adhered to with the exception that in the removal of color from samples 2 and 3 the portions were weighed out into the 50 cc graduated, glass-stoppered flask, acidified as directed, and the piece of fat-free woolen cloth added (about 1.5 inches square). After standing over night the volume was completed with aldehyde-free alcohol, without removing the cloth.

Preliminary tests of the samples were made against a series of standards, but all final determinations were made by matching in the colorimeter. Final comparisons were always arranged so that the depths of tints compared were within 10 per cent, generally less, of equal strength.

Results reported are calculated from averages of four to five readings made in rapid succession with columns of 40 mm and 30 mm, i. e., 8 to 10 readings. Comparisons on the different depths of liquid gave concordant results.

Color in samples 1 (turmeric) and 2 (Naphthol Yellow S) gave no trouble whatever in comparisons. The samples are so highly diluted in the final determination that the color does not interfere. On sample 3 (Naphthol Yellow S) considerably more of the original liquid is present in the comparison tube, due to its lower citral content, and a very slight modification of tint in depths of 40 mm was noticed. With depths of 30 mm there was no apparent difference and tints were matched with ease. Sample 4 (turmeric) behaved similarly to No. 3. In depths of 40 mm there was a slight difference of tint, because nearly 3.5 cc of the original liquid was present in the tube. This slight difficulty disappeared in depths of 30 mm. Samples 2 and 3 were very satisfactorily decolorized by the treatment with the cloth. However, in so far as ease of comparison is concerned this treatment seems superfluous if comparisons are made with comparatively short columns of liquid, as above noted.

A. W. Hansen: The operator could not see that the color interfered with the comparisons.

W. L. Dubois: The comparisons were made in wide Nessler tubes graduated to 100 ce which were cooled to 15° in a large bath and for comparison placed in a tall beaker containing water at 15° and around which was wrapped a piece of white paper, the beaker being set on a white surface and lifted therefrom a few inches at the time of reading. The color in samples 2 and 4 did not seem to interfere with the determinations. The fuchsin sulphite solution when made as directed retained a slightly brownish tint. The fuchsin, however, which we had available for the preparation of this solution was not labeled c. p. and this possibly may have accounted for our failure to get a perfectly colorless solution.

C. L. Cook: None of the readings of any of the samples was interfered with by the presence of the coloring matter used. It was found necessary to allow the fuchsin solution to stand at least forty hours before a blank could be obtained with the aldehydefree alcohol we were able to distil.

F. D. Merrill: Samples 1 and 4 colored with turmeric gave a color differing somewhat from the standard used in the determination of citral. In Nos. 2 and 3 colored with Naphthol Yellow S less difficulty was experienced in matching colors with the standards in the determination of citral when the original extract was used, but when the sample was decolorized by either method suggested it had a very different color as compared with the standard used in citral determination, and great difficulty was experienced in matching colors.

R. S. Hiltner: The small amount of turmeric in samples No. 1 and No. 4 did not interfere perceptibly with the color comparisons.

Sample No. 2, when heated with hydrochloric acid and woolen cloth under reflux condenser as directed, turned brown, apparently due to decomposition of citral. A somewhat similar change took place with No. 3, but to a less degree.

The same result was obtained on these two samples by simply acidifying with hydrochloric acid and treating at once with fuchsin reagent as by allowing the acidified solution to stand over night in contact with wool.

I was unable to secure alcohol that would not respond to the fuchsin test for aldehyde, even after prolonged standing and heating with m-phenylene diamin hydrochlorid.

Besides the figures obtained by the trial method, Mr. Hiltner, of the Denver Food Inspection Laboratory, submitted a set obtained by a method devised by himself using metaphenylene diamin as a substitute for the fuchsin sulphite reagent. The writer makes the following claims for the method:

First. Since there is no color reaction with acetaldehyde, more correct results may be secured in the analysis of commercial extracts.

In the preparation of these extracts, ordinary rectified alcohol is, of course, used. Such alcohol always contains more or less acetaldehyde. Any general reagent for aldehydes, like fuchsin, therefore tends to give too high results for citral because of the reaction on the acetaldehyde present.

Second. It is unnecessary, as stated, to use especially purified alcohol free from aldehydes.

Third. All the operations may be carried on at room temperature.

The following figures were submitted on the official samples: No. 1, 0.251; No. 2, 0.305; No. 3, 0.117; No. 4, 0.061.

Nos. 1 and 2 are somewhat below the average figures submitted by the collaborators. Nos. 3 and 4 are much closer to the actual amount present than those obtained by Mr. Hiltner with the method under trial. As the method was called to the referee's attention only a few days before the meeting, no opportunity was offered to test it this year.

GENERAL DISCUSSION OF RESULTS.

The results obtained on the official samples as a whole exceed greatly the expectations of the referee.

When twelve different analysts are working even with a well-established method under varying conditions, experience has shown that some discordant results are apt to be obtained. When like discrepancies have been obtained with the official methods for nitrogen and potash, it would seem that the results, in the present case, are highly satisfactory.

It appears to be of no advantage to remove the color before making the determinations; in fact, several of the collaborators are of the opinion that it renders the solutions harder to read. The work done at Washington also indicated that there was little advantage to be obtained, certainly not sufficient to offset the loss of citral. The results were slightly better on the alcoholic solutions of citral than upon the extracts. They were better on the terpeneless extract than on the extract containing lemon oil. This is, in all probability, due to the effect of the non-aldehydic constituents upon the color of the fuchsin solution. Where the colors are not of like tint, considerable experience is required in order to correctly match them.

On the final comparisons the standard and sample must contain approximately equal amounts of citral; a deviation of over 10 per cent is not allowable.

The method is not difficult of manipulation, but does require pure reagents, especially in the case of aldehyde-free alcohol. It is highly probable that the greater part of the discordant results are due to the latter. Given a cologne spirit of good quality, there seems, however, to be no reason why good results should not be obtained. It is recommended that the method as submitted for the determination of citral in lemon extracts be adopted provisionally by the association.

REPORT ON SPICES.

By A. L. WINTON, Associate Referee.

The attention of the associate referee was directed to the adulteration of paprika with olive oil, and the methods of detecting this form of adulteration, by papers presented by Doolittle and Ogden and by Loewenstein at the New Haven meeting of the American Chemical Society. Although the time was short for giving this matter suitable attention, a circular letter was sent out on September 5 to such chemists as had previously expressed a willingness to cooperate, and later, samples of two kinds of paprika were distributed, one purporting to be pure, the other adulterated with olive

The methods submitted for study are as follows:

METHODS.

NON-VOLATILE ETHER EXTRACT.

Dry in a desiccator over night or until the moisture is largely removed a sufficient amount of the material to yield an extract of from 0.2 to 0.25 grams. Extract according to the official method for the determination of crude fat (Bul. 107, Rev., p. 39, 5 (b) (1)), collecting the ether solution in a tared flask. Dry the extract at 100° C. for 15-minute periods until constant weight is secured.

IODIN NUMBER.

Determine by the Ianus method (Bul. 107, Rev., pp. 136–7), using the extract obtained as described in the preceding section.

Great care should be exercised in weighing the flask, both before and after extraction, as an error of 1 milligram is equivalent to an error of over 0.5 in the iodin number. A glass-stoppered 200 cc Erlenmeyer flask may be used for the extraction and also, without transfer, for the determination of the fodin number, although in our experience more accurate results may be secured by using a vial-mouth unstoppered flask of about 40 ce capacity, thus reducing the exposed surface to a minimum. In the latter case the flask, after dissolving the extract in chloroform and adding the Hanus solution, is introduced into a saltmouth, glass-stoppered bottle, broken with a glass rod and the titration carried out in this bottle in the usual manner.

It was suggested that in extracting the fat 3 grams of the pure paprika and 2 grams of the paprika adulterated with oil be used, thus securing amounts of extract suitable for determination of iodin number.

ALCOHOL EXTRACT.

Follow the official method (Bul. 107, Rev., p. 163).

DISCUSSION OF RESULTS.

The results obtained by the five analysts who took part in the cooperative work are given in the following table:

Analysis of pure paprika and samples mixed with olive oil.