Stability-Indicating Photochemical Method for the Assay of Riboflavin: Lumichrome Method
Table 4
Assay of RF in photodegraded samples and aged vitamin preparations (25 ± 1°C).
Method
Sample stored in transparent containers (pH 7.0)a
Vitamin preparations stored in original package (pH 3-4)b
Added (mg/100 mL)
Found (mg/100 mL)
% recovery
% RSD
Labeled (mg/100 mL)
Found (mg/100 mL)
% recovery
% RSD
USP fluorimetric methodc
Sample 1
33.2
21.46
64.63
1.39
33.2
30.31
91.29
1.33
Sample 2
24.0
15.16
63.16
1.97
24.0
22.40
93.33
1.75
Sample 3
50.0
35.42
70.84
1.55
50.0
44.75
89.50
1.45
LC methodc
Sample 1
33.2
20.88
62.89
1.97
33.2
29.63
89.24
1.98
Sample 2
24.0
14.80
61.66
1.97
24.0
22.30
92.91
1.81
Sample 3
50.0
35.31
70.62
1.96
50.0
43.99
87.98
1.88
Light for 4 h.
bRoom light for 6 months.
cThe tabulated value at the 95% confidence level for five degrees of freedom is 2.571 and the calculated value is 1.950. Therefore, < and there is no significant difference between the two methods at this confidence level.
