title: Improved liquid chromatography methods for the separation and quantification of biotin in NIST standard reference material 3280: multivitamin/multielement tablets.
abstract: Two independently developed liquid chromatography (LC) methods for the quantitative determination of 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 evaporative light-scattering detection (ELSD)) to ensure quantitative reliability. The use of different extraction and detection procedures allows cross-validation of the methods and enhances confidence in the final 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 SRM 3280, 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 of detection (LOD) and limit of quantification (LOQ) of 0.02 ng (S/N > 3) and 0.06 ng (S/N > 10) biotin on-column, respectively. The LC/ELSD method exhibits good linearity from 155 ng to 9900 ng biotin on-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 analytically superior to the LC/ELSD method; however, either method in combination with SRM 3280 should provide quality assurance, accuracy, and traceability for biotin levels in multivitamin/multielement dietary supplements.
authors.affiliation: National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, Maryland 20899-0001, USA. bryant.nelson@nist.gov
authors.forename: Bryant C
authors.initials: BC
authors.lastname: Nelson
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Sharpless
authors.forename: Lane C
authors.initials: LC
authors.lastname: Sander
mesh_terms: D001710:Biotin / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D008027:Light; D013058:Mass Spectrometry; D012015:Reference Standards; D012542:Scattering, Radiation; D013607:Tablets / Q000032:analysis
chemical_list: D013607:Tablets; D001710:Biotin