586 Philippine Journal of Science 1929 
(curve 2B, fig. 5) seems to furnish the concentration most fa- 
vorable for the oxidation of glucose, when the amount of the 
latter in the reaction mixture does not exceed 40 milligrams. 
In the latter case 0.2 N is again the most favorable concentra- 
tion of alkali. When the concentration of alkali is 0.04 N 
(curve 5B, fig. 5) there seems to be a more uniformly rising 
curve when the amount of glucose is increased from 10 to 40 
Normality of alkali. 
0.04 0.2 0.4 06 08 
3 | 
30 \ 
ae | ae 
SO = aa he Ree paet, |+— 
we 
3 to fan oe Pe 
5 
= } id 
et N 
‘ 20 — Se 
E bern SS N Pa 
4 
E 3 a na 
: Beane be 
sf at | a Mis 
2s = 
3 | 
ie} ae a 
_— 
26 att ot OE e. — 
Se 
10 — |__| 
LT a ce 
as aa Ly oH a 
Ee ea SA 
Fig. 1. Effect of normality of alkali on the amount of potassium permanganate ” 
centimeters of 0.2 N solution reduced to glucose. Curves 1, 2, 3, 4, and 5 are en = 
30, 40, and 50 milligrams, respectively. 
milligrams. When the concentration of potassium permang@ 
nate is 0.05 N (curves C, fig. 5) the differences between the 
effects of the several concentrations of alkali tend to disappear: 
In choosing the concentrations of alkali and of potassium Per 
manganate to be used in devising a method for the quantitativ® 
determination of glucose and starch in agricultural products, 
considered the following points: 
