16,6 Quisumbing: Determination of Glucose and Starch 585 
TABLE 1.—Ovxidation 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. 
Concentration of alkali. 
| 
Glucose. 
| O8N. | 0.6N. | 04N. | 0.2N. | 0.04 N. 
oi ee | 
mg. | | | 
re | 26.26 | 27,24 | 26.52!  30.79| 26.57 
so, Seale tet ge st ie oe le Rac Ueda COO gn oR aE tlh oh UE 24.08 | 24.61 24, 82 27.56 | 23.64 
ELE NT, PLE AON SLL | 17.46) 19.16) 18.42) 22.54) 17.28 
20 Ss EEaREEREEEEEEEEEEEEEEeEEe 13.44 13.47 12.81 16.96 | 12.44 
Mee ee [ £8 ee Ra ae 
\ | | | 
| 
OXIDATION OF GLUCOSE BY 0.1 N POTASSIUM PERMANGANATE. 
| | 
NEO, ORES SOR DEES AE | exss| 2213| 2202} 22.70| 21.80 
ee er | 19.89/ 2186! 20.55! 2161| 21.60 
Bd eg ee ee 17.98) 21.16 | 18.58/  21.05 20.17 
Ride ae pg cbbaienea ce iaetoudes om 16,72 | 18.59} 17.00} 17.41] 17.26 
ES IEE EEA SE ASN PLE oF ET REE TR 10.32; 11.88 | 11.61 11.60 | 10.97 
OXIDATION OF GLUCOSE BY 0.05 N POTASSIUM PERMANGANATE. 
Pe ee a 25.01 24,22 25.30 25.57 | 24.95 
BO reste) metre noes ten oe Pipe 23. 00 22.34 24.24 24.95 | 23.59 
Oe Oe 21.15 21. 15 22. 92 22.85] 22.41 
err 20.12 19. 46 21.56 21.17} 20.15 
Hee BOIS I ae rte eran tent adic treeiea ee eee 12.37 8.13 10.90 11.04 | 12.67 | 
| Oe 7.12 6.38 8.04 7.71 7.41 | 
i 
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 
