Assay for dextrose
Determine the angular rotation of Solution in a suitable polarimeter tube (see
Optical Rotation
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). Where the Solution is labeled to contain anhydrous dextrose, calculate the percentage (g per 100 mL) of C
6H
12O
6 in the portion of Solution taken by the formula:
(100/52.9)AR,
in which 100 is the percentage; 52.9 is the midpoint of the specific rotation range for anhydrous dextrose, in degrees;
A is 100 mm divided by the length of the polarimeter tube, in mm; and
R is the observed rotation, in degrees. Where the Solution is labeled to contain dextrose monohydrate, calculate the percentage (g per 100 mL) C
6H
12O
6·H
2O in the portion of Solution taken by the formula:
(100/52.9)(198.17/180.16)AR,
in which 100 is the percentage; 52.9 is the midpoint of the specific rotation range for anhydrous dextrose, in degrees; 198.17 and 180.16 are the molecular weights for dextrose monohydrate and anhydrous dextrose, respectively;
A is 100 mm divided by the length of the polarimeter tube, in mm; and
R is the observed rotation, in degrees.