A VOLUMETRIC METHOD FOR THE DETERMINATION 
OF LACTOSE BY ALKALINE POTASSIUM PERMAN- 
GANATE 1 
By Felipe T. Adriano 
Of the Laboratory of Agricultural Chemistry, College of Agriculture, 
University of the Philippines 
Quisumbing, (7) of this laboratory, recently devised a volu- 
metric method for the determination of glucose and starch by 
alkaline potassium permanganate solution, which is claimed to 
be shorter than, and as accurate as, any of the Fehling methods, 
either gravimetric or volumetric. It was thought worth while 
to apply this method to the determination of lactose in milk. 
For this purpose a lactose permanganate table similar to that 
for pure lactose for glucose and starch was prepared. Parallel 
determinations of lactose in milk were then made by the new, 
the Soxhlet, and the optical methods. The results show that 
for the determination of sugar in milk the new method, besides 
being more rapid, promises to be as accurate as either of the 
older methods, if not more so. 
PREVIOUS WORK ON MILK SUGAR DETERMINATION 
So far as can be found in the available literature no quan- 
titative method has ever been devised for the determination of 
lactose in milk by oxidation with potassium permanganate in 
alkaline solution. Greifenhagen, Konig, and Scholl (5) deter- 
mined the ration of lactose to the amount of oxygen used when 
the former is oxidized in an alkaline potassium permanganate 
solution, but they did not work out a method for the determina- 
tion of this sugar in milk. Some determinations of lactose by 
the older methods are given here. 
1 This investigation was undertaken at the suggestion and under the 
direction of Prof. M. L. Roxas. Published with the permission of the 
Director of the experiment station of the College of Agriculture, Univer- 
sity of the Philippines. 
172178—6 213 
