16,6 Quisumbing: Determinatmi of Glucose and Starch 585 
Table 1 . — Oxidation of different concentrations of glucose in different con- 
centrations of alkali by 0.2 N, 0.1 N, 0.05 N potassium permanganate 
solutions, respectively. 
[Figures show amounts in cubic centimeters of potassium permanganate reduced by glucose.] 
OXIDATION OF GLUCOSE BY 0.2 N POTASSIUM PERMANGANATE. 
Glucose. 
Concentration of alkali. 
0.8 N. 
0.6 AT. 
0.4 IV. 
0.2 N. 
0.0^^ N. 
mg. 
26. 26 
27. 24 
26. 52 
30. 79 
26. 57 
40 . 
24. 03 
24.61 
24.82 
27.56 
23, 64 
30 - — 
17.46 
19. 16 
18.42 
22.64 
17.23 
20 
13.44 
13. 47 
12. 81 
16. 96 
12.44 
10 
6.27 
7. 59 
6. 41 
10. 81 
6.09 
OXIDATION OF GLUCOSE BY 0.1 
N POTASSIUM PERMANGANATE. 
60 — 
21.36 
22.13 
22.02 
22. 70 
21. 80 
40 
19.89 
21.86 
20. 66 
21.61 
21.60 
30 
17.98 
21. 16 
18. 58 
21.06 
20. 17 
17.26 
20 . 
16.72 
18. 59 
17.00 
17.41 
10 
10.32 
11.83 
11.61 
11.60 
10. 97 
OXIDATION OF GLUCOSE BY 0.05 N POTASSIUM PERMANGANATE. 
25 - 
25.01 ] 
24.22 
25. 30 
25. 57 
24. 95 
20 
23. 00 
22. 34 
24. 24 
24. 95 
23. 59 
15 
21. 15 
21. 16 
22.92 
22.85 
22.41 
10 - 
20. 12 
19. 46 
21.56 
21. 17 
20. 15 
5 
12.37 
8. 13 
10.90 
11.04 
12. 67 
2. 5 
7. 12 
6.38 
8.04 
7.71 
7.41 
These curves bring out the relation between the volume of potas- 
sium permanganate solution and the alkali concentration used 
with varying concentrations of glucose for 0.2 N, 0.1 N, and 
0.05 N potassium permanganate, respectively. The curves in 
figs. 4 and 5 bring out the relation between the amount of glu- 
cose used and the value of potassium permanganate reduced in 
terms of 0.05 N. It is apparent that for 0.2 N potassium per- 
manganate, 0.2 N alkali furnishes the most favorable concen- 
tration for the oxidation of glucose. This is shown by curve 4 
A, fig. 4, in which all the points are above the others. It is to 
be noted that the concentration of alkali in all of these experi- 
ments is the actual concentration in the mixture, while the 
normality of the potassium permanganate is that of the stand- 
ard stock solution used and not that of the mixture. When the 
concentration of potassium permanganate is 0.1 N, 0.6 N alkali 
