A Novel and Sensitive Method for the Determination of Vitamin B_𝟐 (Riboflavin) in Urine and Pharmaceutical Samples Using an Aqueous Two-Phase Extraction

Table 1

Effect of interference on extraction and determination of vitamin B₂.

Foreign species	Tolerance limit (ng/mL)
Cd^2+, NH^4+, Mg^2+, F^−, K^+, Zn^2+, Cu^2+	1000
Glucose, lactose, Hg^2+, S^2−, Br^−, Al^3+	800
Pb^2+, Fe^2+, Ca^2+, Cr^3+, Co^2+, folic acid, vitamin C, vitamin A	400
Oxalate, citrate, tartrate, vitamin D	300
SO4^2−, SO3^2−, NO3^−, PO4^3−	70
I^−, vitamin B1	50
Vitamin B12, vitamin B6	10