Determination of Total Reducing Sugars, Dextrose, and Levulose in Raw Cane Sugars F. W. ZERBAN AND M. H. WILEY,New York Sugar T r a d e Laboratory, New York, N. Y.
I
N A PAPER published some time ago (‘7) the importance
of determining dextrose and levulose in cane products was pointed out, and various ways in which this might be accomplished were discussed. It was concluded that Nijns’s method (6)of estimating levulose by selective copper reduction promised to be useful for the purpose. It was also found that contrary to Nijns’s statement, dextrose has a distinct reducing effect on the copper carbonate reagent, and that large quantities of sucrose reduce it measurably, especially in the presence of reducing sugars. Jackson (3) also found this to be true for a copper carbonate solution similar to Njns’s, but containing 25.3 instead of 15 grams of copper sulfate per liter. The method has been further studied by Jackson and Mathews ( d ) , and their modification has been adopted by the Association of Official Agricultural Chemists (1). Because of the reducing effect of dextrose on the copper carbonate reagent, the determination of levulose in mixtures with other sugars requires a determination of total reducing sugars also. The tables given by Jackson and Mathews for this purpose are not directly applicable to the analysis of raw sugars. Since raw sugars contain large quantities of sucrose with small quantities of dextrose and levulose, a correction for the reducing effect of the sucrose must be applied to the result of the copper carbonate reduction as well as to that of the total reducing sugar determination. While the first of these corrections is known from the work of Jackson and Mathews, the usual tables for reducing sugars in the presence of large
quantities of mcrose consider only invert sugar, but not dextrose and levulose in varying proportions. It was therefore necessary to establish such a table. Following the example of Jackson and Mathews, the Lane and Eynon volumetric method (5) was chosen because it is more practical for routine work than the gravimetric procedures and is rapidly gaining ground in the cane-sugar industry. The Lane and Eynon tables have been extended so as to include columns of factors for levulose and for dextrose in varying proportions, in the presence of large quantities of sucrose, and for 10 ml. of Soxhlet solution. The procedure prescribed by Lane and Eynon was followed in every detaiI, several series of analyses being run with solutions containing 10 and 25 grams, respectively, of sucrose in 100 ml., plus dextrose alone, levulose alone, and invert sugar, ranging in quantity from 90 to 300 mg. of each. The solutions were titrated against 10 ml. of Soxhlet solution. The results were plotted, interpolated, and the final values are shown in Table I. The factors for invert sugar are generally a little higher than those given by Lane and Eynon. This is no doubt due to small differences in manipulation, and each analyst should check these values under his own individual conditions, or construct his own tables of factors. A few check analyses are given in Table 11. In confirmation of a statement made by Lane and Eynon, that in the presence of a large excess of sucrose small variations in the details of the procedure have a much greater
FACTORS FOR MIXTURES OF LEVULOSE AND DEXTROSE TABLE I. LANEAND EYNON (10 ml. of Soxhlet solution) 100 D 90 D 80 D 70 D 60 D 50 D 40 D 30 D 20 D 10 D 0 D 100 D 90 D 80 D 70 D 60 D 50 D 40 D 30 D 20 D 10 D 0 D TITER 0 L 10 L 20 L 30 L 40 L 50 L 60 L 70 L 80 L 90 L 100 L T I T ~ R 0 L 10 L 2O.L 30 L 40 L 50 L 60 L 70 L 80 L 90 L 100 L A.
I N PRBSINCE OF 10 GRAMS OF 8UCROBI I N
B.
1W ML
I N PRIBENCE OP 26 Q R A M S OF 80CROSI I N I W ML.
15 16 17 18 19 20
46.1 46.3 46.5 46.6 46.8 47.0 47.2 47.4 47.7 47.9 48.1 46.0 46.2 46.4 46.6 46.7 46.9 47.1 47.3 47.6 47.8 48.0 46.0 46.2 46.4 46.5 46.7 46.9 47.1 47.3 47.5 47.7 47.9 45.9 46.1 46.3 46.4 46.6 46.8 47.0 47.2 47.5 47.7 47.9 45.9 46.1 46.3 46.4 46.6 46.8 47.0 47.2 47.4 47.6 47.8 45.8 46.0 48.2 46.3 46.5 46.7 46.9 47.1 47.3 47.5 47.7
15 16 17 18 19 20
42.9 43.1 43.2 42.9 43.0 43.2 42.8 42.9 43.1 42.7 42.8 43.0 42.7 42.8 42.9 42.6 42.7 42.9
21 22 23 24 25
45.7 45.9 46.1 46.2 46.4 46.6 46.8 47.0 47.2 47.4 47.6 45.7 45.9 46.0 46.1 46.3 46.5 46.7 46.9 47.1 47.3 47.5 45.6 46.8 46.0 46.1 46.3 46.5 46.7 46.9 47.1 47.3 47.5 45.6 45.8 45.9 46.0 46.2 46.4 46.6 46.8 47.0 47.2 47.4 45.5 45.7 45.8 45.9 46.1 46.3 46.5 46.7 46.9 47.1 47.3
21 22 23 24 25
42.5 42.6 42.8 42.9 43.0 43.1 43.3 42.5 42.6 42.8 42.9 43.0 43.1 43.2 42.4 42.5 42.7 42.8 42.9 43.0 43.1 42.4 42.5 42.6 42.7 42.8 42.9 43.0 42.3 42.4 42.5 42.6 42.7 42.8 42.9
26 27 28 29 30
45.4 45.6 45.7 45.9 46.0 46.2 46.4 46.6 46.8 47.0 47.2 45.4 45.6 45.7 45.8 46.0 46.2 46.4 46.6 46.7 46.9 47.1 45.3 45.5 45.6 46.8 45.9 46.1 46.3 46.5 46.7 46.9 47.1 45.3 45.6 45.6 45.7 45.9 46.1 46.3 46.4 46.6 46.8 47.0 45.2 45.4 45.5 45.7 45.8 46.0 46.2 46.4 46.5 46.7 46.9
26 27 28 29 30
42.2 42.2 42.1 42.1 42.0
31 32 33 34 35
45.2 45.4 45.5 45.6 45.7 45.9 46.1 46.3 46.4 46.6 46.8 45.1 45.3 45.4 45.6 45.7 45.9 46.1 46.3 46.4 46.6 46.8 45.1 45.3 45.4 45.5 45.6 45.8 46.0 46.2 46.3 46.5 46.7 45.0 45.2 45.3 45.5 45.6 45.8 46.0 46.2 46.3 46.5 46.7 45.0 46.1 45.3 45.4 45.6 45.7 45.9 46.1 46.2 46.4 46.6
31 32 33 34 35
41.9 42.0 42.1 42.2 42.3 42.4 42.5 42.6 42.7 42.8 42.9 41.9 42.0 42.1 42.2 42.3 42.4 42.5 42.6 42.7 42.8 42.9 41.8 41.9 42.0 42.1 42.2 42.3 42.4 42.6 42.6 42.7 42.8 41.7 41.8 41.9 42.0 42.1 42.2 42.3 42.4 42.5 42.6 42.7 41.6 41.7 41.8 41.9 42.0 42.1 42.2 42.3 42.4 42.5 42.6
36 37 38 39 40
45.0 45.1 45.3 45.4 45.6 45.7 45.9 46.1 46.2 46.4 46.6 45.0 45.1 45.3 45.4 45.6 45.7 46.9 46.0 46.2 46.4 46.5 44.9 46.0 45.2 45.3 46.5 45.6 46.8 46.0 46.1 46.3 46.5 44.9 45.0 45.2 45.3 45.5 45.6 45.8 45.9 46.1 46.3 46.4 44.9 45.0 45.2 45.3 45.5 45.6 45.8 45.9 46.1 46.3 46.4
36 37 38 39 40
41.6 41.7 41.8 41.5 41.6 41.7 41.5 41.8 41.7 41.4 41.5 41.8 41.3 41.4 41.5
41 42 43 44 45
44.9 45.0 45.2 44.9 46.0 45.2 44.8 44.9 45.1 44.8 44.9 45.1 44.8 44.9 45.1
45.3 45.5 45.6 45.8 45.9 46.1 46.3 46.4 45.3 45.6 45.6 45.7 45.9 46.0 46.2 46.3 45.2 45.4 45.5 45.7 46.8 46.0 46.2 46.3 45.2 45.4 45.5 45.6 45.8 46.9 46.1 46.2 45.2 45.4 45.5 45.6 45.8 45.9 46.1 46.2
41 42 43 44 45
41.2 41.1 41.1 41.0 40.9
46 47 48 49 50
44.8 44.9 45.1 45.2 45.4 45.5 45.6 45.8 46.9 46.1 46.2 44.8 44.9 45.1 46.2 45.4 45.5 46.6 45.8 45.9 46.1 46.2 44.7 44.8 45.0 45.1 45.3 45.4 45.5 45.7 45.8 46.0 46.1 44.7 44.8 45.0 45.1 45.3 45.4 45.5 45.7 46.8 46.0 46.1 44.7 44.8 45.0 46.1 45.3 45.4 45.5 45.7 45.8 46.0 46.1
46 47 48 49 50
40.8 40.9 41.0 41.1 41.2 41.3 41.4 41.5 41.6 41.7 41.8 40.7 40.8 40.9 41.0 41.1 41.2 41.3 41.4 41.5 41.6 41.7 40.7 40.8 40.9 41.0 41.1 41.2 41.3 41.4 41.5 41.6 41.7 40.6 40.7 40.8 40.9 41.0 41.1 41.2 41.3 41.4 41.5 41.6 40.5 40.6 40.7 40.8 40.9 41.0 41.1 41.2 41.3 41.4 41.5
354
42.3 42.4 42.6 42.7 42.3 42.4 42.5 42.6 42.2 42.3 42.4 42.6 42.2 42.3 42.4 42.5 42.1 42.2 42.3 42.4
42.8 42.7 42.6 42.6 42.6
43.5 43.6 43.7 43.9 43.4 43.6 43.7 43.8 43.3 43.4 43.6 43.7 43.2 43.3 43.5 43.6 43.1 43.2 43.4 43.6
42.9 43.0 43.2 43.3 43.4 42.8 42.9 43.1 43.2 43.3 42.7 42.8 43.0 43.1 43.2 42.7 42.8 42.9 43.0 43.1 42.6 42.7 42.8 42.9 43.0
41.9 42.0 42.1 42.2 42.3 42.4 42.6 42.6 41.8 41.9 42.0 42.1 42.2 42.3 42.4 42.5 41.8 41.9 42.0 42.1 42.2 42.3 42.4 42.5 41.7 41.8 41.9 42.0 42.1 42.2 42.3 42.4 41.6 41.7 41.8 41.9 42.0 42.1 42.2 42.3
41.3 41.4 41.5 41.6 41.7 41.8 41.9 42.0 42.1 42.2 41.2 41.3 41.4 41.5 41.6 41.7 41.8 41.9 42.0 42.1 41.2 41.3 41.4 41.5 41.6 41.7 41.8 41.9 42.0 42.1 41.1 41.2 41.3 41.4 41.5 41.6 41.7 41.8 41.9 42.0 41.0 41.1 41.2 41.3 41.4 41.5 41.6 41.7 41.8 41.9
September 15,1934
INDUSTRIAL AND ENGINEERING CHEMISTRY
effect than in the absence of sucrose, it is found that the precision is not quite as high as when reducing sugars alone are present, but it is nevertheless satisfactory for routine analyses of raw sugars. TABLE11. DETERMIXATIOXS OF TOTAL REDUCING SUGARSBY LANEAND EYNON'S METHOD 10 GRAMS OF SUCROSE I N 1M) ML. O F S O L U T I O N
Dextrose mg. Levulose mg.
taken, taken,
120.0 108.2 70.5 125.0 43.5 43.6
72.7
137.9 65.7 150.5 125.0 138.0 82.0
36.0 186.9
64.1
---- ----
Total
257.9 173.9 221.0 250.0 181.5 125.6 108.7 251.0
Titerfound ml. 18.15 26.6 21.4 18.6 25.9 36.9 42.5 18.8 Total found, mg. 258.4 172.9 219.6 251.6 180.3 124.7 106.8 251.6 26 GRAMS
Dextrose
taken,
mg.
Levulose taken,
OF SUCROSE I N 1W ML. O F S O L U T I O N
237.9 156.0 85.5 156.5 123.0 41.5 37.5 132.5 106.3
56.0 53.7 86.5
56.5
50.0
47.8
98.5
mg.
- _ _ _ _ _ - - ~ - -
Total
275.4 288.5 191.8 212.5 176.7 128.0 104.3 148.5
Titer found, ml. 15.6 15.2 22.35 20.3 24.0 33.05 40.25 28.7 Totalfound,mg. 276.3 287.2 192.8 211.8 178.3 128.6 103.6 149.1
The use of Jackson and Mathews' modification of Nijns's method for the determination of levulose was next investigated from the standpoint of raw sugar analysis. An electrically heated water bath, with automatic thermostat control within 0.1" C., was employed for the purpose, and the directions of Jackson and Mathews were followed, except that 250-ml. flasks had t o be used instead of the 150-ml. size which is no longer on the market. The reduced copper was determined gravimetrically, as in the previous investigation. A number of analyses were made with different quantities of levulose, and the bath temperature was so regulated that after 75 minutes' heating the results checked with those given in Jackson and Mathews' table. This was found to be the case when the water surrounding the immersed portion of the flasks indicated 55.2" C.
35;
crose plus 40 mg. of dextrose. This is of little importance in the analysis of raw sugars, because these always contain a certain proportion of levulose, To test the combination of the Lane and Eynon and the Jackson and Mathews methods, mixtures of sucrose with 0.5, 1.0, and 1.5 per cent of total reducing sugars were prepared and analyzed as outlined above. I n the case of the mixtures containing 1.5 per cent of total reducing sugars the Lane and Eynon titration was carried out after diluting 100 ml. of the original solution to 250 ml., and figuring back to the original concentration. The results, calculated as described by Jackson and Mathews, are shown in Table 111. For a n indirect method, the results are satisfactory. When dextrose alone is present in addition to sucrose (Nos. 5, 10, and 15), the correction of 8.5 and 9 mg. of copper for the sucrose effect (a) is too high. A correction of 4.6 mg. in Nos. 5b and 10b gave zero levulose, in 15b 0.02 per cent of levulose; for 5 grams of sucrose and 1.5 per cent of dextrose (No. 15), the proper correction is 7.3 mg. of copper.
PROCEDURE A number of raw cane sugars were next analyzed by the following procedure:
A solution of the raw sugar, containing 25 grams of sucrose in each 100 ml. is prepared (the direct polarization may be taken to e ual the sucrose in most cases without serious error). A total 0?250 ml. of solution is usually sufficient. The solution is clarified with neutral lead acetate solution before being made up t o the mark. It is filtered, deleaded with dry potassium oxalate, and refiltered. Two 20-ml. portions of the final solution are used to determine in duplicate the reducing effect on the copper carbonate solution, according to Jackson and Mathews. The copper in the precipitate is determined volumetrically by Mohr's ferric sulfate and permanganate method, since weighing usually gives too high results because of contamination; electrolytic reduction, or the chromic acid-ferrous sulfate method of Jackson and Mathews may also be used. The remainder of the filtrate is used for the Lane and Eynon titrations, and the factor is found from Table IB. If the titer is less than 15 ml., 100 ml. of the TABLE 111. ANALYSES OF SUGAR MIXTURES BY A COMBINATIONclarified solution are diluted to 250 ml., the new solution now OF METHODS containing 10 grams of sucrose in 100 ml., and the factor is found from Table IA. If, on the other hand, the t'iter of the original FOUND. clarified solution is over 50 ml., a new solution of the raw sugar Copper corLane is prepared and a known quantity of levulose or invert sugar is TAKENrected & added, as suggested for such cases by Eynon and Lane (2). The SuLevu- Dexfor Eynon LevuDexadded reducing sugar is later corrected for. crose losea trosea Copper sucrose titer lose trose C -
5 5 5
85.9 67.7 47.5 27.8 8.4 8.4
76.9 58.7 38.5 18.8
4 4 4 4 4 4
1.00 0.75 0.50 0.25 0.00 0.00
0.00 0.25 0.50 0.75 1.00 1.00
142.8 108.5 73.2 42.1 11.3 11.3
134.3 100.0 64.7 33.6 2.8 6.7
46.0 1.01 -0.01 45.8 0.75 0.25 45.4 0.49 0.52 44.5 0.24 0.77 44.2 -0.05 1.06 44.2 0.00 1.01
1.50 0.00 1.125 0.375 0.75 0.75 0.375 1.125 0.00 1.50 0.00 1.60 sucrose
266.9 207.0 142.9 84.2 21.8 21.8
257.9 198.0 133.9 75.2 12.8 17.2
31.5 1.50 -0.02 30.5 1.11 0.41 30.6 0.75 0.75 30.6 0.39 1.10 30.0 -0.07 1.58 30.0 0.02 1.49
6 7 8 9 10a 10b
a
%
MQ.
0.00 0.125 0.25 0.375 0.50 0.50
5 5
11 12 13 14 15, 15b
%
Mg. 0.50 0.375 0.25 0.125 0.00 0.00
G./dO mZ.
1 2 3 4 5a 5b
6
5 5 5 5 5 6 Per cent of
-0.6
3.8
34.0 33.8 33.6 33.5 33.5 33.5
0.49 0.38 0.26 0.12 -0.05 0.00
0.01 0.13 0.25 0.38 0.55 0.50
Mixtures of levulose and dextrose in varying proportions, with 4 and 5 grams, respectively, of sucrose in 20 ml. total volume were analyzed next, and the corrections established by Jackson and Mathews for the effect of dextrose and sucrose were confirmed. One milligram of levulose has the same reducing power as 12.4 mg. of dextrose; 4 grams of sucrose reduce 8.5 mg. of copper, and 5 grams of sucrose 9.0 mg. of copper. When no levulose is present, however, the reducing effect of sucrose is much smaller. Jackson and Mathews found that 5 grams of sucrose alone give only 2.4 mg. of copper; the writers found 4.6 mg. copper reduced by 5 grams of sucrose plus 25 mg. of dextrose, or 4 grams of su-
CALCULATIONS The method of calculation is shown in the following example : Sucrose, per cent in r a w sugar Grams of raw sugar containing 100 grams of sucrose
96.75 103.36
A sample of 64.60 grams of raw sugar (103.36 X 6/8) was dissolved in a 250-ml. flask, and clarified as described above. The Lane and Eynon titer was found to be 18.13 ml. Since the ratio between levulose and dextrose is not known as yet, the first calculation is based on the factor for invert sugar in Table I B which is 43.4. This gives 100 X 43.4/18.13 or 239.4 mg. o! total reducing sugars, as invert, in 100 ml. of solution. With the Jackson and Mathews method 76.9 mg. of reduced copper were found. Corrected for the reducing effect of the sucrose, this gives 76.9 - 9.0 or 67.9 mg. of copper. According to jackson and Mathews' table, this corresponds to 22.0 mg. of apparent levulose in 20 ml. of solution, or 110.0 mg. in 100 ml. of solution. MB. Total reducing sugars as invert Apparent levulose, first approximation Apparent dextrose, first approximation, 239.4 Equivalent levulose, 129.4:12.4
.
239.4 110.0
- 110.0
Apparent levdose, second approximation, 110.0
- 10.4
Apparent dextrose, second approximation, 239.4 Equivalent levulose, 139.8:12.4
- 99.6
129.4 10.4 99.6 139.8 11.3
Apparent levulose, third approximation, 110.0
- 11.3
98.7
Apparent dextrose, third approximation, 239.4
- 98.7
140.7
ANALYTICAL EDITION
356
OF LEVULOSE AND DEXTROSE IN TABLEIV. DETERMINATIONS RAWCANESUGARS
NO.
1 2 3 4 5
R
ORIGIN Cuba Philippines Hawaii Puerto Rico Florida Santo Domingo
DBXTROSELEYULOBE
TOTAL REDUCINQ SUGARS
%
%
%
0.542 0.671 0.176 0.559 0.426 0.342
0.382 0.557 0.261 0.531 0.402 0.446
0.924 1.228 0.437 1.090 0.828 0.788
The levulose equivalent of the dextrose, 140.7:12.4, is again 11.3 mg., so that the figures for levulose and dextrose, third ap roximation, are not changed further. $he ratio between levulose and dextrose is thus found t o be 98.7:140.7, or as 41:59. For this ratio Table IB gives a Lane and Eynon factor of 43.3 instead of 43.4, and the total reducing sugars are therefore not 239.4, but 238.8 mg. In this articular case a second calculation, on the basis of 238.8 mg. oPtotal reducing sugars, is hardly necessary, because the difference is within the limits of error. If it is made, the second calculation gives 98.7 mg. of levulose and 140.1 mg. of dextrose in 100 ml. of
Vol. 6 , No. 5
solution or in 25.84 grams of raw sugar. The final result is therefore 0.382 per cent of levulose, 0.542 per cent of dextrose, 0.924 per cent of total reducing sugars. The results of the analyses of this and other raw sugars are compiled in Table N.
LITERATURE CITED Assoc. Official Agr. Chem., J . Assoc. Oficial Agr. Chena., 15, 5 3 (1932).
Eynon and Lane, J . Soc. Chem. Ind., 50, 85T (1931). Jackson, J . Assoc. Oficial Agr. Chem., 9, 178 (1926); 11, 1 7 5 (1928); 12, 166 (1929).
Jackson and Mathews, Ibid., 15, 198 (1932) ; Bur. Standards J.Research, 8, 403 (1932). Lane and Eynon, J. SOC.Chem. Ind., 42, 32T (1923). Nijns, Sucr. belge, 44, 210 (1924). Zerban and Sattler, IND.ENO.CHEY.,Anal. Ed., 2, 307 (1930). RECEIVED April 10, 1934. Presented before the Division of Sugar Chemistry at the 87th Meeting of the American Chemical Society, St. Petersburg, Fla., March 25 to 30, 1934.
Extraction of Gossypol from Cottonseed Meal Effect of Moisture and Repeated Extraction with Ether by Different Procedures J. 0. HALVERSON AND F. H. SMITH, Agricultural Experiment Station, Raleigh, N. C.
I
PI; A PREVIOUS paper ( 2 ) data were presented showing that moisture both in the cottonseed meal and in the ether exerted a marked influence on the amount of gossypol which could be extracted. These data suggested that there is no definite limit between the ether-soluble and bound gossypol. More data are presented here to substantiate those results and to show further what occurs when cottonseed meal is repeatedly moistened and extracted with ether, and with ether saturated with water. Initial charges of 75 grams of cottonseed meal were moistened or conditioned ( 2 ) by passing a vapor of condensing steam over thin layers of meal for 5 hours, or, more conveniently, the proper amount of water was mixed in with a mortar and pestle, The conditioned meal was extracted for 72 hours and the gossypol estimated by a recently published modified method (1).
subsequent extraction. It was therefore decided to determine how much ether-soluble gossypol could be extracted from meal 1578, which had previously shown a total (bound and ethersoluble) gossypol content of 1.102 * 0.006 per cent ( 3 ) . The repeated conditioning and extraction of the charge was continued as long as appreciable amounts of gossypol could be obtained. TABLEI. GOSSYPOL RECOVERED FROM MOISTENED COTTONSEED MEALBY SUCCESSIVE EXTRACTIONS WITH ETHERBY DIFFERENT PROCEDURES EXTRACTION
PERioDs
%
The U. S. P. grades of ether (not for anesthesia) obtained from the General Chemical Company and J. T. Baker Chemical Company (designated in the text as G and B ethers, respectively) have consistently yielded discordant amounts of gossypol. Consequently, experiments were undertaken to determine the quantity of gossypol which could be extracted from the same cottonseed meal by the following procedure: Group a, determinations 1 to 3 with G ether alone Group b, determinations 4 t o 6, with B ether alone Group c, determinations 7 and 8, with B ether, 10 cc. of alcohol (95 per cent), and 5 cc. of water Group d, determinations 9 and 10, with €3 ether and 5 cc. of water Preliminary work showed that' meal conditioned by increasing its moisture content yielded more ether-soluble gossypol upon successive moistening of the charge of meal and
Mg.
70
Mo.
%
%
Mg.
Mg.
AVERAGE GOSSYPOL A N D MOISTURE PER DETERMINATION
1 to 6
7to14
1 5 t o 17
ETHER-SOLUBLE GOSSYPOLFROM MOISTENEDCOTTONSEED MEAL
(Average mg. of gossypol per 100 grams of meal) GROUPc GROUPd GROUPb GROUPa Mois- Gossy- Mois- Gossy- Mois- Gossy- Mois- Gossyture pol ture pol ture pol ture pol 20.2 16.0 24.0 7.1 26.2 1.0
19.4 25.8 24.5
24.7 5.7 2.1
19.5 27.4 24.4
38.0 3.5 1.8
20.3 30.1 24.6
37.7 4.8 0.9
AVERAGE TOTAL GOSSYPOL PER DETERMINATION
1 to 6 7 to 14 15 to 17
96.1 56.5 3.0
148.2 45.2 6.3
228.2 28.3 5.3
Per cent
0.1556
0.1997
0.2618
226.0 38.3 2.7 0.2670
In the first six successive periods of extraction an average of 16.0 mg. of gossypol per determination was obtained by the G ether in group a, compared to 24.7 mg. by the B ether in group 6 (Figure 1 and Table I). The moisture content of the charges in these groups does not vary greatly and is adequate for the extraction. Groups r and cl yielded an average of 38.0 and 37.7 mg. of gossypol per determination, respectively, considerably more than groups a and b. This large difference is apparently due to the addition of water to the ether in the receiving flask, since the moisture content of the charges in the various groups is approximately the same. The discrepancy in the yield of gossypol for groups a and b compared
