No. 6.
v01. XXVIII.
THE JOURNAL OF THE
American Chemical Society u. s. DEPARTMENTO F AGRICULTURE, BUREAU SENT BY H. w. WIZEY.]
[CONTRIBUTION FROM THE OF CHEMISTRY.
THE UNIFICATION OF REDUCINCi SUGAR METHODS. BY
I,.
S. MUNSON AND PERCY H. WALKER.
Received April 2, 1906.
SINCEFehlingl proposed the use of an alkaline copper tartrate solution for the quantitative estimation of reducing sugars, a large number of independent methods have been worked out having as their basis the power of these sugars to reduce such a copper solution. Among the most important and most generally used of these may be mentioned: Allihn’s method for d-glucose.2 Meissl’s method for invert sugar alone, and in the presence of amounts of sucrose varying between 90 and 99 per cent.s Hiller’s method for invert sugar in presence of less than go per cent. sucrose.“ Herzfeld’s method for I per cent. or less of invert sugar and a high percentage of sucrose. Soxhlet’s method for lactose.E Soxhlet’s method for maltose.
‘
Ann. 72, 106. J. pr. Chem. 22,46 (1880). 3
6 6 7
2. Ver. Rubenzucker Ind. 29, I034 (1879). Ibid. 39, 734 (1889). Ibid. 35,985 ( 1 8 8 5 ) . J. pr. Chem. 21, 227 (1880). Allg. Brau. Hopf. Ztg., 1885.
664
I,. S. MUNSON A N D PERCY H. WALKER.
Brown, Morris and Millar’s method for d-glucose, &fructose and invert sugar. Kjeldahl’s method for d-glucose, 8-fructose, invert sugar maltose, lactose and galactose. Defren’s method for d-glucose, maltose and lactose. In all of the above methods the copper sulphate solution used has remained practically identical, rzz., 34.639 grams crystallized copper sulphate in joo cc., which is very nearly the same concentration as was suggested by Fehling in 1850. The alkaline tartrate solutions and the methods of manipulation employed by the different analysts, however, have varied materially and as both of these factors have a marked effect upon the copper reducing powers of the different sugars, these variations constitute the principal differences in the methods above mentioned. This work upon reducing sugars was taken up, therefore, for the purpose of so unifying the methods of analysis that a single set of solutions and a common method of manipulation might be used for all reducing sugars. This necessitated a consideration of the solutions to be employed with reference to their effect upon non-reducing sugars when present ; the time required for making the determination ; the accuracy and simplicity of the method, and the most satisfactory manner of conducting the reduction. It was also necessary that due consideration be given to methods that had long been in use, and consequently radical change from which might be made with reluctance, The solutions of copper sulphate and of alkaline tartrate, commonly known as Soxhlet’s solutions, were accepted as the most satisfactory for general use and these solutions have probably been more generally used in the past than any other set. Besides, these solutions are the ones employed almost exclusively, in this country at least, for volumetric work. In the manner of making the reductions, two widely different general methods have been employed. Almost invariably the older workers have employed direct boiling for a short period, while the later workers, Brown, Morris and Millar, Kjeldahl, and 1 The name which is accepted b>r international scientific usage is eniployed throughout this paper in place of “dextrose,” which is more comnlonly used in American technical literature. J. Chem. SOC.71, 275 (1897). -1 Compt. rend. des travaux du laboratoire d e Carlsberg, 1895, p. I . 4 This Journal, 18, 749 (1896).
REDUCING SUGAR METHODS.
665
Defren, have employed heating in a boiling water-bath, conducting the reduction for a longer period than where direct boiling is practised. Kjeldahl, in addition, made the reduction in an atmosphere of hydrogen, thus avoiding the effect of atmospheric oxidation, but this precaution makes the method too cumbersome to permit of its general use. In reference to the manner of conducting the reduction, advantages seemed to be largely in favor of direct boiling for a short period. In an investigation of this subject by one of us1 it was shown that while somewhat higher results were obtained by heating in boiling water for a long period, the reduction even at the end of fifteen minutes was far from complete and that chances of surface oxidation were much greater than by direct boiling. The method of boiling over a free flame was therefore accepted. PREPARATION OF SOLUTIOXS AND METHOD OF MANIPULATION.
Copper sulphate solution must contain 34.639 grams of crystallized copper sulphate of highest purity in 500 cc. This salt should contain not more than mere traces of iron. Alkaline tartrate solution must contain 173 grams of Rochelle salt and 5 0 grams of sodium hydroxide in 500 cc. The amount of alkali to be used is best obtained by weighing out a concentrated solution of sodium hydroxide, the strength of which has been determined by titration. It is not considered essential that this solution be prepared fresh each day, as many workers recommend. In case any precipitate separates out this is filtered off before using; otherwise our experience has been that this solution undergoes no material change upon standing for reasonable lengths of time. Manipulation.-Transfer 2 5 cc. each of the copper and alkaline tartrate solutions to a 400 cc. Jena or Non-sol beaker and add 50 cc. of reducing sugar solution, or, if a smaller volume of sugar solution be used, add water to make the final volume IOO cc. Heat the beaker upon an asbestos gauze over a Bunsen burner, so regulate the flame that boiling begins in four minutes, and continue the boiling for exactly two minutes. Keep the beaker covered with a watch-glass throughout the entire time of heating. Without diluting, filter the cuprous oxide a t once on an asbestos felt in a porcelain Gooch crucible, using suction. Wash the 1
Proc. A. 0. A. C., Bur. Chem., Bull. 73, p. 59.
666
L. S. MUNSOK AND PERCY H. WALKER.
cuprous oxide thoroughly with water a t a temperature of about 60' C.., then with IO cc. of alcohol and finally With I O cc. of ether. Dry for thirty minutes in a water oven a t IOO', cool in a desiccator and weigh as cuprous oxide. Direct Weighing of Cuprous Oxide.-This method of determining copper has been practised in the laboratories of the Bureau of Chemistry for a number of years and has given most excellent results. The method was checked several years ago' against the electrolytic method and later against Low's thiosulphate method as described in this Journal, 24, IOSZ ( ~ g o z ) , and the accuracy of the cuprous oxide method demonstrated.2 It is by far the most convenient method for the copper determination, the only precaution necessary in its use being the preparation of the asbestos, It has been the custom here to prepare the asbestos, which should be the amphibole variety, by first digesting with I : 3 hydrochloric acid for two or three days. Wash free from acid and digest for a similar period with soda solution, after which treat for a few hours with hot alkaline copper tartrate solution of the strength employed in sugar determinations. The asbestos is then washed free from alkali, finally digested with nitric acid for several hours, and after washing free from acid it is shaken up with water for use. In preparing the Gooch crucible load it with a film of asbestos one-fourth inch thick, wash this thoroughly with water to remove fine particles of asbestos; finally wash with alcohol and ether, dry for thirty minutes a t IOO', cool in a desiccator and weigh. It has been found most convenient to dissolve the cuprous oxide each time after weighing, with nitric acid, and use the same felts over and over again, as they improve with use. Twenty-
' Proc. A. 0. A. C., Bur. Chem., Bull. 73, p. jg.
' For pure d-glucose and invert sugar t h e copper
contained in the cuprous oxide corresponds within the limits of experimental error to t h e theoretical amount. The same is true with the mixture of invert sugar and sucrose when 400 milligrams of total sugar are used. For the mixture containing two grams total sugar, t h e copper content of the precipitate is slightly lower than theory indicates but the variation is not great enough to affect the results ; besides, the results recorded are based on the weights of t h e precipitate and not on the content of copper. When as much as IO grams total sugar are used, the variation from the theory may amount to several milligrams, but this variation is constant and would introduce no error when working with tables based on direct weighing of cuprous oxide.
REDUCING SUGAR METHODS.
667
six crucibles were thus used throughout this work and the average loss for an average of seventeen determinations with each crucible was but 0.39 mg. each determination. This loss is partly mechanical and results partly from the solvent action of the reagents used. Sfiontaneous Precipitation of Cuprous Oxide.-When alkaline copper tartrate is boiled, a slight spontaneous precipitation of cuprous oxide takes place and the regular determinations should be corrected by the amount of cuprous oxide thus precipitated. In this work each one of us ran two blanks each day that determinations were made and the results of each worker are corrected by his blanks for that day. In this way proper correction is made for the cuprous oxide precipitated spontaneously as well as for any loss of asbestos, through solvent action of the alkaline liquid. The following table shows the blanks obtained throughout this investigation. Attention is called to the rather wide range shown by some of these blanks. Working in the manner above described the copper-reducing power of d-glucose, invert sugar, and two mixtures of invert sugar and sucrose was determined. All weights of sugar and of cuprous oxide are expressed in terms of brass weights in air. The flasks and pipettes used were accurately graduated by the Bureau of Standards and all were very close to their indicated volumes. In no case was the error introduced by their use sufficient to take into consideration. Pure d-glucose was prepared by repeatedly recrystallizing the commercial product. The material finally used showed for (a)’,” a value of 53.17, with a concentration of 2 0 per cent., which value corresponds very clbsely to that calculated according to Tollen’s formula. Pure sucrose was prepared according to the method prescribed by the International Commission for Unifying Methods of Sugar Analysis, and the product used was shown to be of the highest purity. Invert sugar was prepared from this sucrose by hydrolyzing with fifth-normal hydrochloric acid, using IO cc. of this acid for each IOO cc. final volume of invert sugar solution and heating upon the steam-bath for thirty minutes. The solution was then cooled rapidly, the acid barely neutralized with fifthnormal sodium hydroxide, and the volume completed at the
668
.,I S. MUNSOK AND PERCY H. WALKKER.
TABLEI. Individual blanks. _-_A_-_
Number of set.
Munson. Mgs.
Walker. Mgs.
0.4
I
I
.o
0.2
4
0.5
0.j
0.0
0.2
0.0
0.0
1.6 0.5
6
i
8
0.3
0.2
0.3
0.6
0.6
0.4
0.4
2.0
-0. j
I .o
-0.5
1.6
0.6
1.3
0.4
0.8
0.8
0.9
I
0.5
0.6
0.5 0.3
I4
0.3
0.0
-0.3
-0.
I
0.0
--o.
2
I
.o
0.I
0.3
0.4
0.3
0.6
0.5
0.4
0.5
1.2
-0.5
1.3
1.1
0.6
0.7
0.8
0.I
0.4
-0.2
0.I
.o
0.2
I
0.0
0.0
4.I 17
0.0
.o
-0.4
-0.4
16
0.I
...
0.6
13
0.8
0.8 ---o. 5
0.2
I2
15
0.0
0.3 0.8
IO
0.0
-0.4
0.8 --o. 2
9
I1
0.2
0.4 -.4
Walker. Mgs.
-0.4
-0.6 5
Mgs.
-0.6
-0.7
3
hIunson.
1.4
1
-0.
2
Average. ?---h_--
0.0
-.
3
-1.3
-0.
I
--I
.o
-0.
I
0.5
0.0
0.0
-0.2
-1.2
REDUCING SUGAR METHODS.
669
temperature of graduation of the flask. Care was taken to retain this temperature until all portions were measured out. In all cases a t least two different solutions were used in establishing each point and duplicate determinations were made by each worker. Points were determined 2 0 mgs. apart, beginning with 20 mgs. for each of the sugars and mixtures. With the invert sugar and sucrose mixtures, the requisite amount of cane-sugar was obtained by measuring with a burette a sucrose solution of known concentration. Results of all determinations for the four series are given in Table 11. From the averages for each series a curve was drawn upon cross-section paper and by use of these curves the individual determinations that were sufficiently far from the curve to be considered among the less accurate of the determinations made were eliminated from the final averages. While all determinations made for each point are recorded, greatest weight was given to those lying nearest the curve. Those determinations not included in final averages are indicated by a star. When working with either d-glucose or invert sugar alone, the results obtained were very uniform and agreed within reasonable limits of experimental error. With the mixtures of invert sugar and sucrose, however, results were less uniform, especially where large amounts of sucrose were present. Two sugar mixtures were worked upon, one containing a total of 0.400 gram invert sugar and sucrose and the other a total of 2,000 grams. By reference to the tables it is seen that the presence of sucrose materially increases the reduction, the amount of increase being influenced primarily by the amount of sucrose present and secondarily by the amount of invert sugar present. The amount of sucrose remaining the same, its influence will be less when a large amount of reducing sugar is present than when only a small amount is present. In using a definite amount of total sugar, the authors have followed the plan carried out by Herzfeld in his method of determining I per cent. or less of invert sugar in the presence of large amounts of sucrose, and it is believed that this method of procedure will give much more satisfactory results with a less amount of analytical work than does the method of Meissl and Hiller, upon the basis of which tables have been worked out for definite percentages of invert sugar and sucrose.
670
I,. S. MUNSON AND PERCY H. WALKER.
From each series of average results as given in Table I1 was deduced, according to the method of least squares, the formula for calculating reducing sugar from any weight of cuprous oxide within limits of the method. In these formulas y=cuprous oxide and x =reducing sugar. For d-glucose, y = 0.5614 2.3484 x -0.001209 x2. For invert sugar alone, ~=-0.2460+2.2747 x - 0 . 0 0 1 0 ~ 7 x'. For invert sugar and sucrose, 0.400 gram total, ~/=6.3886+2.2279 x -0.0009703 x'. For invert sugar and sucrose, 2.000 grams total, y=20.6600+2.2021 X - O . O O O g O ~ O X 2 . From these formulas the points of each series corresponding to the determined points were calculated, and in Table I11 are given the determined and the calculated values of each series together with the differences between these values. With dextrose, invert sugar, and the invert sugar and sucrose mixture of 0.400 gram total, these differences are very small and negligible. The 2,000 grams mixture showed less concordance, although satisfactory results were obtained. Table IV gives the sugar values for each series of reducing sugars for each milligram of cuprous oxide between IO and 490. The values for points IO milligrams apart, beginning with IO m i l k grams of cuprous oxide, were calculated from the formula and all intermediate points were determined by interpolation. The copper equivalents of cuprous oxide given in the second column of this table were obtained by multiplying cuprous oxide by 0.88827. When this work was taken up it was hoped that factors might be worked out for all of the more important reducing sugars and for such mixtures as seemed nec.essary. To date, however, only the factors for d-glucose, invert sugar and two mixtures of invert sugar and sucrose have been determined. In continuing this investigation it will be necessary to do further work on other invert sugar and sucrose mixtures. Maltose and lactose are other important reducing sugars for which the present methods of determination are not entirely satisfactory, and the authors hope to take up the work on these within the next few months.
+
... ... ...
t . . n . . e" m
.. .. .. . . . 0'. . m .. . m
h
,
. . .. . . . .
v)
v ) .
h
m
,
. . .
m
e
2
:
O
. PI. h.
h n h m m rr,
m m m
. N.
h
m m m m d--k
h10h
.
0
e
.
:
h m N
*
t? 9 ? $molti
m m m
" 0 N
m N
N
0
0 7 0 ?
. h. h. v .)
w
a
??'4
t
mv)v)v)
N ' 0 0 * N N m m
.,I S. MUXSON AXD PERCY H. WALKER.
674
TABLEIV. Cuprous oxide
Copper
(CU20).
(CU).
Mgs.
IO
Mgs.
Mgs.
8.9 9.8
4.0
4.5 5.0
2. I
5.4 5.8 6.3
2.5
3.9 4.3 4.8 5.2 5.7 6.I 6.6
I2
IO. j
13
11.5
'4
12.4
4.5 4.9 5.3 5.7
'5 16 '7 I8 '9
13.3 14.2
6.2 6.6
15. I
7.0
16.0 16.9
7.5
7.9
6.7 7.2 7.6 8.I 8.5
20 22
17.8 18.7 19.5
23
20.4
8.3 8.7 9.2 9.6
8.9 9.4 9.8 10.3
21
21.3
25 26 27 28 29 30
26.6 27.5 28.4 29.3
I1
21
Invert sugar Invert sugar and sucrose. and sucrosc. 0.400 gram. 2.0000 grams. Total mgs. Total mgs.
[nvert sugar. Mgs.
&Glucose
10.0
IO,j
22.2
IO.5
11.2
23.I
IO.g 11.3 11.8
11.6
24.0
12.0
1.6
3.0
3.4
7.0
7.5 7.9 8.4 8.8 9.3 9.7
12.2
12.5 12.9
30.2
12.6 13.I 13.5 '3.9 14.3
13.4 13.8 14.3 14.7 15.2
35 36 37 38 39
31.1 32.0 32.9 33.8 34.6
14.8 15.2 15.6 16.I 16.5
15.6 16.I 16.5 16.9 17.4
13.4 13.8 14.3 14.7
40
43 44
35.5 36.4 37.3 38.2 39.1
16.9 17.4 17.8 18.2 18.7
17.8 18.3 18.7 19.2 19.6
15.2 15.6 16.I 16.6 17.0
45 46 47
40.0 40.9 41.7
19.I 19.6
20. I
20.0
21.0
17.5 17.9 18.4
31
32
33 34
41
42
24.9 25.8
20.5
IO.2 IO.7 11.1
4.3 4.7
11.6
5.2
12.0
5.6 6.I
12.j
12.9
6.5 7.0 7.4 7.9 8.4 8.8 9.3 9.7 IO. 2
IO.7 11.1
11.6 12.0
675
REDUCING SUGAR METHODS.
TABLEIV- Continued. Invert sugar Invert sugar and sucrose. and rucrose. z.oooo rams. 0.400 gram. Totafmgs. Total mgs.
Cuprous oxide (CuaO). Mgs.
Copper (CU). Mgs.
48 49
42.6 43.5
20.4
21.4 21.9
18.8 19.3
12.5
20.9
50
52 53 54
44.4 45.3 46.2 47.1 48.0
21.3 21.7 22.2 22.6 23.0
22.3 22.8 23.2 23.7 24.I
19.7 20.2 20.7 21.1 21.6
13.4 13.9 14.3 14.8 15.2
55 56 57 58 59
48.9 49.7 50.6 51.5 52.4
23.5 23.9 24.3 24.8 25.2
24.6 25.0 25.5 25.9 26.4
22.0 22.5 22.9 23.4 23.9
15.7 16.2 16.6 17.I 17.5
60
25.6
62 63 64
53.3 54.2 55.1 56.0 56.8
26.5 27.0 27.4
26.8 27.3 27.7 28.2 28.6
24.3 24.8 25.2 25.7 26.2
18.0 18.5 18.9 19.4 19.8
65 66 67 68 69
57.7 58.6 59.5 60.4 61.3
27.8 28.3 28.7 29.2 29.6
29.I 29.5 30.0 30.4 30.9
26.6 27. I 27.5 28.0 28.5
20.3 20.8 21.2 21.7
70 71 72 73 74
62.2 63.I 64.0 64.8 65.7
30.0 30.5 30.9 31.4 31.8
31.3 31.8 32.3 32.7 33.2
28.9 29.4 29.8 30.3 30.8
22.6 23.I 23.5 24.0 24.5
75 76 77 78 79
66.6 67.5 68.4 69.3 70.2
32.2 32.7 33.1 33.6 34.0
33.6 34.1 34.5 35.0 35.4
31.2 31.7 32.I 32.6 33.1
24.9 25.4 25.9 26.3 26.8
80 81 82 83 84
71.I 71.9 72.8 73.7 74.6
34.4 34.9 35.3 35.8 36.2
35.9 36.3 36.8 37.3 37.7
33.5 34.0 34.5 34.9 35.4
27.3 27.7 28.2 28.6 29.I
51
61
d-Glucose. Mgs.
26.I
Invert sugar. Mgs.
12.9
22.2
676
L. S. MUNSON A N D PERCY H. WALKER.
TABLEIS'-Continued. Cuprous oxide
Invert sugar Invert sugar and sucrose. and sucrose. 2.0000 grams. 0.400 gram. Total mgs. Total mgs.
hrgs.
Copper (CUI. hlgs.
d-Glucose. Mgs.
Invert sugar. Mgs.
85 86 87 88 89
75.5 76.4 77.3 78.2 79.1
36.7 37.1 37.5 38.0 38.4
38.2 38.6 39.1 39.5 40.0
35.8 36.3 36.8 37.2 37.7
29.6 30.0 30.5 31 .o 31.4
90 91 92 93 94
79.9 80.8 81.7 82.6 83.5
38.9 39.3 39.8 40.2 40.6
40.4 40.9 41.4 41.8 42.3
38.2 38.6 39.1 39.6 40.0
31.9 32.4 32.8 33.3 33.8
95 96 97 98 99
84.4 85.3 86.2 87. I 87.9
41.1 41.5 42.0 42.4 42.9
42.7 43.2 43.7 44.1 44.6
40.5 41 .o 41.4 41.9 42.4
34.2 34.7 35.2 35.6 36. I
IO0
88.8 89.7 90.6 91.5 92.4
43.3 43.8 44.2 44.7 45. I
45.0 45.5 46.0 46.4 46.9
42.8 43.3 43.8 44.2 44.7
36.6 37.0 37.5 38.0 38.5
93.3 94.2 95.0 95.9 96.8
45.5 46.0 46.4 46.9 47.3
47.3 47.8 48.3 48.7 49.2
45.2 45.6 46. I 46.6 47.0
38.9 39.4 39.9 40.3 40.8
97.7 98.6 99.5 100.4 101.3
47.8 48.2 48.7 49.1 49.6
49.6 50. I 50.6 51 .o 51.5
47.5 48.0 48.4 48.9 49.4
41.3 41.7 42.2 42.7 43.2
115 I 16 117 I18 119
102.2
50.0
103.0 103.9 104.8 105.7
50.5
49.8 50.3
50.9 51.4 51.8
51.9 52.4 52.9 53.3 53.8
51.2 51.7
43.6 44.1 44.6 45.0 45.5
I20
106.6 107.5
52.3 52.7
54.3 54.7
52.2 52.7
46.0 46.5
(CUZO).
IO1 I02
103 104 I05 I 06
107 I08 I09 I10 111
I12
113 1I 4
I21
50.8
REDUCING SUGAR METHODS.
677
TABLEIV-Continued. Invert sugar. Mgs.
Invert sugar and sucrose. 0.400 gram. Total mgs.
53.2 53.6 54.1
55.2 55.7 56. I
53.1 53.6 54.1
46.9 47.4 47.9
111.9 112.8 113.7 114.6
54.5 55.0 55.4 55.9 56.3
56.6 57.0 57.5 58.0 58.4
54.5 55.0 55.5 55.9 56.4
48.3 48.8 49.3 49.8
115.5 116.4 117.3 118. I 119.0
56.8 57.2 57.7 58. I 58.6
58.9 59.4 59.8 60.3 60.8
56.9 57.4 57.8 58.3 58.8
50.7 51.2 51.7
119.9 120.8 121.7 122.6 123.5
59.0 59.5 60.0 60.4 60.9
61.2 61.7 62.2 62.6 63. I
59.3 59.7 60.2 60.7 61.2
53. I 53.6 54.0 54.5 55.0
124.4
61.3 61.8 62.2 62.7 63. I
63.6 64.0 64.5 65.0 65.4
61.6 62. I 62.6 63. I 63.5
55.5 55.9 56.4 56.9 57.4
129.7 130.6 131.5 132.4
63.6 64.0 64.5 65.0 65.4
65.9 66.4 66.9 67.3 67.8
64.0 64.5 65.0 65.4 65.9
57.8 58.3 58.8 59.3 59.7
133.2 134. I 135.0 135.9 136.8
65.9 66.3 66.8 67.2 67.7
68.3 68.7 69.2 69.7 70. I
66.4 66.9 67.3 67.8 68.3
60.2 60.7 61.2 61.7 62. I
'37.7 138.6 139.5 140.3
68.2 68.6 69. I 69.5
70.6 71. I 71.6 72.0
68.8 69.2 69.7 70.2
62.6 63. I 63.6 64. I
Copper (CU).
Mgs.
108.4 109.3 110. I 111.0
125.2
126. I 127.0
127.9 128.8
d-Glucose Mgs.
Invert sugar and sucrose.
2.0000 grams.
Total mgs.
50.2
52. I
52.6
I,, S. MUNSON AND PERCY H. WALKER.
678
TABLE IV-Continued. Cuprous oxide (Cq0).
Copper
Invert sugar. Mgs.
Invert sugar and sucrose. 0.400 gram. Total mgs.
Invert sugar and sucrose. z.oooo grams. Total mgs.
Mgs.
E;;:
d-Glucose. Mgs.
I59
141.2
70.0
72.5
70.7
64.5
I 60
142. I 143.0 143.9 144.8 145.7
70.4 70.9 71.4 71.8 72.3
73.0
71.2
73.4 73.9 74.4 71.9
71.6 72. I 72.6 73. I
65.0 65.5 66.0 66.5 66.9
146.6 147.5 148.3 I49 2
72.8 73.2 73.7 74.1 74.6
75.3 75.8 76.3 76.8 77.2
73.6 74.0 74.5 75.0 75.5
67.4 67.9 68.4 68.9 69.3
75.1
77.7
75.5 76.0 76.4 76.9
78.2 78.7
76.0 76.4 76.9 77.4 77.9
69.8 70.3
I73 I74
151.0 151.9 152.8 153.7 154.6
I75 I 76 I77 178 I79
155.5 156.3 157.2 158. I 159.0
77.4 77.8 78.3 78.8 79.2
80.6 81.0 81.5 82.0
78.1 78.8 79.3 79.8 80.3
72.2 72.7 73.2 73.7 74.2
I 80
159.9 160.8 161.7 162.6 163.4
79.7 80. I 80.6 81.I 81.5
82.5 82.9 83.4 83.9 84.4
80.8 81.3 81. j 82.2
82.j
74.6 75. 1 75.6 76. I 76.6
186 187 I88 189
164.3 165.2 1G6. I 167.0 167.9
82.0 82.5 82.9 83.4 83.9
84.9 85.3 85.8 86.3 86.8
83.2 83.7 84.2 84.6 85. I
77.' 77.6 78.0 78.5 79.0
190 191 192 I93 I94
168.8 169. j 170.5 171.4 172.3
84.3 84.8 85.3 85.7 86.2
87.2 8;. j 88.2 88.7 89.2
85.6 86. I 86.6 87. I 87.6
79.5
161 162 163 164 165 166 167 I 68 169 170
171 172
181
182 183 184 185
-
I 50.I
79.1 79.6 80. I
70.8
71.3 71.7
80.0
80.5 81.0
81.4
679
REDUCING SUGAR METHODS.
TABLEIV-Colttinued. Cuprous oxide. (CunO). Mgs.
Copper (CU). Mgs.
p-Glucose. Mgs.
Invert sugar. Mgs.
Invert sugar Invert sugar and sucrose. and sucrose. 2.0000 grams. 0 . 4 gram. ~ Total mgs. Total mgs.
I95 196 I97 198 I99
173.2 174.1 175.0 175.9 176.8
86.7 87.I 87.6 88.I 88.5
89.6 go.I 90.6 91.1 91.6
88.0 88.5 89.0 89.5 90.0
81.9 82.4 82.9 83.4 83.9
200
204
177.7 178.5 179.4 180.3 181.2
89.0 89.5 89.9 90.4 90.9
92.0 92.5 93.0 93.5 94.0
90.5 91.0 91.4 91.9 92.4
84.4 84.8 85.3 85.8 86.3
205 206 207 208 209
182.I 183.0 183.9 184.8 185.6
91.4 91.8 92.3 92.8 93.2
94.5 94.9 95.4 95.9 96.4
92.9 93.4 93.9 94.4 94.9
86.8 87.3 87.8 88.3 88.8
210
186.5 187.4 188.3 189.2 190.I
93.7 94.2 94.6 95.1 95.6
96.9 97.4 97.8 98.3 98.8
95.4 95.8 96.3 96.8 97.3
89.2 89.7 go.2 90.7 91.2
191.0 191.9 192.8 193.6 194.5 195.4
96.I 96.5 97.0 97.5 98.0 98.4
99.3 99.8 100.3 100.8
97.8 98.3 98.8 99.3 99.8 100.3
91.7 92.2 92.7 93.2 93.7 94.2
98.9 99.4 99.9 100.3
102.2
100.8 101.2 101.7
224
196.3 197.2 198.I 199.0
94.7 95.1 95.6 96.I
225 226 227 228 229
199.9 200.7 201.6 202.5 203.4
100.8 101.3 101.8 102.2 102.7
230 231
204.3 205.2
103.2 103.7
201 202
203
211 212
213 214 215 216
217 218 219 2 20
221 222
223
101.2
101.7
102.7 103.2 103.7
102.2
104.6 105.I 105.6
104.2
106. I
104.7
96.6 97.I 97.6 98.I 98.6
106.6
105.2 105.7
99.1 99.6
104.2
107.I
102.7 103.2 103.7
680
..I S. MUNSON AND PERCY H. WALKER
TABLEIV-Codinued. Cuprous oxide (CUlO). Mgs.
Copper
E;:
d-Glucose. xgs.
Invert sugar. Alp.
Invert sugar and sucrose. 2 . 0 0 grams. ~ Total mgs.
232 233 2 34
206.I
104. I
IO;.
104.6
108. I
106.2 106.7
100. I
207.0
207.9
105. I
108.6
107.2
101. I
235 236 23i 238 239
208.7 209.6
109.I 109.5
108.2
102. I
110.0
108.7
102.6
211.4
105.6 106.0 106. j 107.0
110. j
109.2
212.3
IO;. j
111.0
109.6
103.I 103.5
210.j
6
Invert sugar and sucrose. 0.400 gram. Total mgs.
10;.
7
100.6
101.6
2 40
213.2
108.0
111.5
110.I
104.0
241
2 1 4 .I
108.4
112.0
110.6
104.j 10j.0
242
215.0
108.9
112.j
111.1
243
215.8
109.4
111.6
105.5
244
216.7
109.9
113.0 113.5
112. I
106.0
112.6 113.I 113.6
106.j
114. I
108.0
114.6
108.j
245
217.6
110.4
114.0
246 247
218.j
110.8
114.5
219.4
111.3
IIj.0
248
220.3
1II.S
249
221.2
112.3
115.4 115.9
250
222.I
112.8
116.4
115.1
25I
223.0 223.8
113.2 113.7
1rj.6
109.o 109.5
224.7
114.2 114.7
116.9 117.4 117.9 118.4
1I,j.2
107.0
107.5
116. I
110.0
116.6
110.j
Ili.I
111.0
118.9
117.6
111.5
118.I
112.0
118.6
112.5
119. I
llj.1
119.4 119 9 I20 4 120.9
119.6
113.0 113.5
231.0
117.6
121.4
120. I
114.0
231,s 232.7 233.6 234.5
118.1
I21
120.6
114.5
262 263 264
118.6
122.4
121. I
11j.0
119.0
122.9
121.6
11j.5
119.j
123.4
122. I
116.0
265 266 267 268
235.4 236.3 237.2 238.I
120.0
123.9
122.6
116. j
120.5
124.4
117.0
121.0
124.9
123.I 123.6
11;. j
1 2 1 .j
125.4
124. I
115.0
25 2
253 254 25.5
225.6 226.j
2j6 257
227.4 228.3
258 259 260
229.2
115.; 116.I 116.6
230.I
26I
.9
68 I
REDUCING SUGAR METHODS.
TABLE IV-Continued. d-Glucose. Mgs.
Invert sugar. Mgs.
Invert m g a t and sucrose. 0.400 gram. Total mgs.
Invert sugar and sucrose. 2.0000 grams. Total mgs.
238.9
122.0
125.9
124.6
118.5
122.5
122.9 123.4 123.9 124.4
126.4 126.9 127.4 127.9 128.4
125. I
119.0 119.5
272 273 274
239.8 240.7 241.6 242.5 243.4
275 276 277 278 279
244.3 245.2 246. I 246.9 247.8
124.9 125.4 125.9 126.4 126.9
128.9 129.4 129.9 130.4 130.9
127.7
121.6
128.2
122.1
128.7 129.2 129.7
122.6 123.1 123.6
280 28 I 282 283 284
248.7 249.6
131.4 131.9 132.4 132.9 133.4
130.2 130.7 131.2 131.7 132.2
124. I 124.6
251.4 252.3
127.3 127.8 128.3 128.8 129.3
285 286 287 288 289 290 291
253.2 254.0 254.9 255.8 256.7 257.6 258.5
129.8 130.3 130.8 131.3 131.8 132.3 132.7
133.9 134.4 134.9 135.4 135.9 136.4 136.9
132.7 133.2 133.7 134.3 134.8 135.3 135.8
126.6 127. I 127.6
292 293 294 295 296
259.4 260.3 261.2 262.0 262.9
133.2 133.7 134.2 134.7 135.2
'37.4 137.9 138.4 138.9 139.4
136.3 136.8 137.3 137.8 138.3
130.2 130.7 131.2 131.7 132.2
297 298 299
263.8 264.7 265.6 266.5 267.4
135.7 136.2 136.7 137.2 137.7
140.0 140.5 141.o 141.5 142.0
138.8 139.4 139.9 140.4 140.9
132 7 '33.2 133.7 134.2 134.8
268.3 269. I
138.2 138.7 139.2 139.7
142.5 I43 .o 143.5 144.0
141.4 141.9 142.4 142.9
135.3 135.8 136.3 136.8
Cuprous oxide (CUZO).
Copper
269 2 70
Mgs.
271
300
30 I 302 303 304 305
E:;
250.5
270.0
270.9
125.6 126.2 126.7 127.2
120.0
120.6 121. I
125. I
125.6 126. I
128. I
128.6 129.2 129.7
682
L. S. MUNSON AND PERCY H. WALKER.
TABLEIV-Conti?itucd. Cuprous oxide (CU20). Mgs.
Copper (CU).
Mgs.
d-Glucose. nIgs.
Invert sugar. Mgs.
Invert sugar and sucrose. 0.400 gram. Total mgs.
306
271.8
140.2
144.5
143.4
137.3
307 308 309 3'0 311
272.7 273.6 274.5 275.4 276.3
140.7 141.2 141.7 142.2 142.7
145.0 145.5 146. I 146.6 147. I
144.0 144.5 '45.0 145.5 146.0
137.8 138.3 138.8 139.4 139.9
312 313 314 3'5 316
277.1 278.0 278.9 279.8 280.7
143.2 143.7 144.2 144.7 145.2
147.6 148. I 148.6 149. I I49 * 6
146.5 147.0 147.6 148. I 148.6
140.4 140.9 141.4 141.9 142 * 4
317 3'8 319 320 3-21
281.6 282.5 283.4 284.2 285. I
145.7 146.2 146.7 147.2 147.7
150. I 150.j
'49. I 149.6
151.2
150.I
151.7
150.7 151.2
143.0 143.5 144.0 144.5 145.0
322 323 324 325 326 327 328
286.0 286.9 287.8 288.7 289.6 290.5 291.4
148.2 148.7 149.2 149.7
152.7 '53.2 153.7 154.3 154.8 155.3 155.8
152.7 153.2 153.8 154.3 154.8
329 330 331 332 333
292.2 293.1 294.0 294.9 295.8
156.3 156.8 157.3 '57.9 158.4
155.3 '55.8 156.4 156.9 157.4
334 335 336 337 338
296.7 297.6 298.5 299.3 300.2
157.9 158.4
155.8 156.3
158.9 159.4 159.9 160.5
339 340 34 1 342
301. I 302.0 302.9 303.8
156.8 157.3 157.8 158.3
150.2
150.7 151.2
151.7 152.2
152.7 153.2 153.7 154.2 154.7 155.2
152.2
151.7 152.2
Invert sugar E U sucrose. ~ grams. Total mgs.
2.0000
145.5 146.0 146.6 147. I 147.6 148. I 148.6 149.1 149.7 150.1
150.7 151.2
161.0
159.5 160.0
151.7 152.3 152.8 153.3 153.8
161.5 162.0 162.5 163.1
160.5 161 .o 161.6 162. I
154.3 154.8 155.4 155.9.
159.0
REDUCING SUGAR METHODS.
683
TABLEIV-Continued. cup~ous oxide
Copper
(CU20).
(CU).
Invert sugar. Mgs.
Invert sugar and sucrose. 0.400 gram. Total Mgs.
Invert sugar and sucrose. z.ooca grams. Total mgs.
156.4 156.9 157.5 158.0
Mgs.
d-Glucose. Mgs.
343 344 345 346 347 348
304.7 305.6 306 * 5 307.3 308.2 309.1
158.8 159.3 159.8 160.3 160.8 161.4
163.6 164. I 164.6 165. I 165.7 166.2
162.6 163. I 163.7 164.2 164.7 165.2
159.0
349 350 351 352 353
310.0 310.9 311.8 312.7 313.6
161.9 162.4 162.9 163.4 163.9
166. j 167.2 167.7 168.3 168.8
165.7 166.3 166.8 167.3 167.8
159 * 5 160. I 160.6 161. I 101.6
354 355 356 357 358
314.4 315.3 316.2 317. I 318.0
164.4 164.9 165.4 166.0 166.5
169.3 169.8 170.4 170.9 171.4
168.4 168.9 169.4 170.0 170.5
162.2 162.7 163.2 163.7 164.3
359 360 361 362 363
318.9 319.8 320.7 321.6 322.4
167.0 167.5 168.0 168.5 169.0
171.9 172.5 173.0 173.5 174.0
171.0 171.5 172. I 172.6 173.1
164.8 165 * 3 165.8 166.4 166.9
364 365 366 367 368
323.3 324.2 325.1 326.0 326.9
169.6 170. I 170.6 171.1 171.6
174.6 175.1 175.6 176.1 176.7
173.7 174.2 174.7 175.2 175.8
167.4 167.9 168.5 169.0 169.5
369 3 70 371 372 373
327.8 328.7 329.5 330.4 331.3
172. I 172.7 173.2 173.7 174.2
177.2 177.7 178.3 178.8 179.3
176.3 176.8 177.4 177.9 178.4
170.0 170.6 171.1 171.6
374 375 376 377 378
332.2 333. I 334.0 334.9 335 * 8
174.7 175.3 175.8 176.3 176.. 8
179.8 180.4 180.9 181.4
179.0 179.5
182.0
181.I
172.7 173.2 173.7 174.3 174.8
379
336.7
177.3
182.5
181.6
175.3
Mgs.
180.0
180.6
158.5
172.2
L. S. MUNSOK AND PERCY H. WALKER.
684
TABLEIV-Continued. cuprous oxide (CU20).
Mgs.
380
381 382 353
copper (CUI. Mgs.
337.5 338.4 339.3 340.2
d-Glucose. Mgs.
Invert sugar. Mgs.
177.9 178.4 178.9 179.4
183.0
180.0
180.j
185.2 185.7
181.0
186.2
181.5
183.6 184.I 184.6
Invert sugar Invert sugar and sucrose. a n d sucrose. 0.400 gram. 2.0000 grams. Total mgs. Total mgs.
IS?.I 182.7 183.2 r83.8
175.9 176.4 176.9
184.3 184.8 185.4 185.9 186.4
178.0 178.5 179. I 179.6
17;. j
384 38s 386 387 388
341. I 342.0 342.9 343.8 344.6
182.0
186.8 187.3
389 390 391 392 393
345.5 346.4 347.3 348.2 349. I
182.6 183. I 183.6 IS4.I 184. 7
187.8 188.4 188.9 189.4 190.0
187.0 187.5 188.0 188.6
161.2 181. 7
189. I
182.8
394 395 396 397 398
350.0 350.9 351.8 352.6 353.5
185.2 185.7
190. j 191 .o 19r. 6 192. I 192.7
189.7 190.2 190. 7 191.3 191.8
183.3 183.9 184.4 184.9 I85 5
399 400 401
168.9 189.4 189.9
193.2 193.7 '94.3 194.8 '95.4
192.3 192.9 193.4 194.0 194.5
186.0 186. j 187.1
403
354.4 355.3 356.2 357. I 358.0
404 405 406 407 408
358.9 359.7 360.6 361.5 362.4
190.5 191 .o 191.5 192. I 192.6
195.9 196.4 197.0 197.5 198. I
195.0 195.6 196. I 196.7 197.2
188.7 189.2 189.8 190.3 190.8
409 410
363.3 364.2 365. I 366.0 366.9
193.1 193.7 194.2 194.7 195.2
198.6 199.1 199.7 200.2
197.7 198.3 198.8 199.4 199.9
'91.4 191.9 192.5 193.0 193.5
367.7 368.6 369.5
195.8 196.3 196.8
200. j
'94. I 194.6 195.2
402
41 I 412
413 4'4
415 -116
186.2
186.8 187.3 187.8 188.4
200.8
201.3 201.8 202.4
201.0 201.6
180. I
180.6
182.3
187.6 188. I
685
REDUCING SUGAR METHODS.
TABLEIV-Continued. cuprous oxide
Invert sugar. Mgs.
Invert sugar and sucrose. 0,400 gram. Total mgs.
I97 4 I97 * 9
202. g
202. I
203.5
202.6
195.7 196.2
198.4 199.0 199.5
204.0 204.6 205. I 205 * 7 206.2
203.2 203.7 204.3 204.8 205.4
196.8 197.3 197.9 198.4 198.9
206.7 207.3 207.8 208.4 208. g
205.9 206.5
200.0
207.0
200.
207.6 208. I
201. I
202.2
210.6
208.7 209.2 209.8
211.1
210.3
206.0
211.7
210.9
203.3 203.8 204.4
206.5
212.2
211.4
204.9
207. I
212.8 213.3 213.9 214.4
212.0
205.5
212.5 213. I 213.6
206.0 206.6
214.2 214.7 215.3 215.8 216.4
207.7 208.2 208.8 209.3 209.9 210.4
220.0
216.9 217.5 218.0 218.6 219. I
220.5
219.7
I
220.2
213.2 213.7 214.3 214.8 215.4
(CuaO).
Mgs.
Copper (CU). Mgs.
&Glucose. Mgs.
417 418
370 * 4 371.3
4'9 420 42 I 422 423
372 * 2 373. I 374.0 374.8 375.7
424 425 426 427 428
376.6 377 * 5 378.4 379.3 380.2
429 430 43 I 432 433
381.1 382.0 382 * 8 383.7 384.6
203.8 204.4 204.9 205.5
434 435 436 43 7 438
385.5 386.4 387.3 388.2 389.1
207.6 208.2 208.7
439 440 441 442 443
390.0 390.8 391.7 392.6 393.5
209.2 209.8 210.3 210.9 211.4
444 445 446 447 448
394.4 395.3 396.2 397. I 397.9
212.5 213. I 213.6 214. I
449 450
398.8 399.7 400.6 401.5 402.4
214.7 215.2 215.8 216.3 216.9
45 1
45 2 453
9
200. I
200.6 201. I
201.7 202 * 2
202.8 203.3
212.0
209.5 210.0
215.0 215.5
216. I 216.6 217.2
217.8 218.3 218.9 219.4
221.
221.6 222.2
222.8
220.8 221.4 221.9
Invert sugar and sucrose.
2.0000 grams.
Total mgs.
199.5 6
201.7
202.7
207. I
211.0 211.5 212. I
212.6
686
REDUCING SUGAR METHODS,
TABLEI V- Cmztimed. Cuprous oxide (CUZO). Mgs.
Copper (CU).
d-Glucose. Mgs.
454 455 456 457 458
403.3 404.2 405. I 405.9 406.8
217.4 218. j 219. I 219.6
459
407.7 408.6 409.5 410.4 411.3
220.2 220. 7 221.3 221.8 222.4
227.2
412.2 413.0 413.9 414.8
228.9 229. j 230.0 230.6 231.2
228. I 228.6 229.2 229.7 230.3
223. I 223. j
460
46 1 462 463
Mgs.
218.0
Invert sugar. Mgs.
Invert sugar Invert sugar and sucrose. and sucrose. _. 0.400 gram . z.oomgrams. Total mgs. Total mgs.
223.3 223.9 224.4 22j.O 225. j
222.5 223.0 223.6 224. I 224. j
217.6 218. x
226. I 226. j
225.3 225.8 226.4 226.9 227.5
218. 7 219.2 219.8 220.3 220.9
227.8 228.3
215.9 216. j 217.0
464 465 466 46 7 468
415.7
222.9 223.5 224.0 224.6 225. I
469 470 47 I 472 473
416.6 417.5 418.4 419.3 420.2
225.7 226.2 226.8 227.4 227.9
231.7 232.3 232.8 233.4 234.0
230.9 231.4 232.0 232.5 233.1
224.2 224.8 225.3 225.9 226.4
474 475 4 76 477 478
421 .o 421.9 422.8 423.7 424.6
228. j 229.0 229.6 230. I 230.7
234.5 235. I 235.7 236.2 236.8
233.7 234.2 234.8 235.4 235.9
227.0
479 480 48 1 48 2 483
425.5 426.4 427.3 428. I 429.0
231.3 231.8 232.4 232.9 233.5
237.4 237.9 238.5 239. I 239.6
236.5 237.1 237.6 238.2 238.8
229.8 230.3 230.9 231.5 232.0
484 485 486 487 488
429.9 430.8 431.7 432.6 433.5
234. I 234.6 235.2 235.7 236.3
240.2 240.8 241.4 241.9 242.5
239.3 239.9 240.5 241 .o 241.6
232.6 233.2 233.7 234.3 234.8
489 490
434.4 435.3
236.9 237.4
243. I 243.6
242.2 242.7
235.4 236.0
CONTRACTS LABORATORY.
221.4 222.0 222. j
227.6 228. I 228.7 229.2
