文摘
Two independently developed liquid chromatography (LC) methods for the quantitative determinationof biotin in multivitamin/multielement tablets (NIST Standard Reference Material 3280 (SRM 3280))are described. The methods use distinctly different tablet extraction solvents (methanol vs 1.5%aqueous formic acid) and analyte detection principles (mass spectrometry (MS) versus evaporativelight-scattering detection (ELSD)) to ensure quantitative reliability. The use of different extractionand detection procedures allows cross-validation of the methods and enhances confidence in thefinal quantitative results. Both methods yield highly comparable results for the mean level of biotin(LC/MS = 26.5 mg/kg ± 0.3 mg/kg (n = 12); LC/ELSD = 24.7 mg/kg ± 1.7 mg/kg (n = 12)) in SRM3280, yet the methods differ considerably in their analytical characteristics. The isotope-dilution LC/MS method exhibits excellent linearity from 0.02 ng to 77 ng biotin on-column with a method limit ofdetection (LOD) and limit of quantification (LOQ) of 0.02 ng (S/N > 3) and 0.06 ng (S/N > 10) biotinon-column, respectively. The LC/ELSD method exhibits good linearity from 155 ng to 9900 ng biotinon-column with a method LOD and LOQ of 155 ng (S/N > 3) and 310 ng (S/N > 10) biotin on-column, respectively. Method performance data indicates that the LC/MS method is analyticallysuperior to the LC/ELSD method; however, either method in combination with SRM 3280 shouldprovide quality assurance, accuracy, and traceability for biotin levels in multivitamin/multielementdietary supplements.