Biotin Analysis of Commercial Vitamin and Other Nutritional Supplements

Abstract

Because previous observations suggest that biotin may be present in vitamin preparations not labeled as containing biotin, we determined the biotin content of several over-the-counter vitamin and nutritional supplements said to contain biotin (group 1) and several in which biotin content was not specified (group 2). Biotin concentration was measured using the 125I-avidin assay which detects total avidin-binding substances. Water extracts were assayed for free biotin and acid hydrolysates were assayed for total biotin. The results of the 125I-avidin assay agreed with the stated biotin content for most vitamin and nutritional supplements in group 1. Biotin was the only avidin-binding substance in the preparations from group 1, based on reversed-phase chromatography. However, some vitamin and nutritional supplements in group 2 contained nutritionally significant amounts of biotin, particularly if the supplement contained liver or yeast extract. Total biotin was significantly higher than free biotin in one supplement; the difference was attributable to release of biotin rather than a biotin analog. We conclude that biotin may be present in some vitamin and nutritional supplements not labeled as containing biotin; biotin intake might be under-estimated if the subject is receiving a nutritional supplement containing extracts of liver or yeast.

Identification and Characterization of Spontaneous Auxotrophic Mutants in Fusarium langsethiae

“…Both cereal flour and rice flour media promoted toxin production [58]. These media contain yeast extract at 1 g/L, which is rich in biotin [61]. In our experiments, phototrophic strains are able to produce comparable levels of mycotoxins on the media regardless of the presence of vitamins.…”

Improved Liquid Chromatography Methods for the Separation and Quantification of Biotin in NIST Standard Reference Material 3280: Multivitamin/Multielement Tablets

“…The LC methods described in this report for the quantification of biotin in multivitamin/multielement supplements are specific for supplements that do not contain yeast, yeast extracts, or liver extracts. Yeast, yeast extracts, and liver extracts contain small but significant amounts of biotin covalently bound to protein (16). Multivitamin/ multielement supplements which contain yeast or liver must undergo alternative extraction procedures, for example, acid hydrolysis, to release the protein-biotin complex.…”

“…Determination of biotin in dietary supplements, on the other hand, only requires appropriate solubilization of the free (non-protein-bound) biotin. The quantitative determination of biotin in a variety of multivitamin/ multielement supplements has been successfully accomplished via affinity-binding methodology-solid-phase 125 I-avidin binding assay (16). However, the binding assay suffers from the need to use and dispose of a radioactive material ( 125 I), an inability to discriminate between biotin and biotin metabolites, and a lengthy (2-day) sample analysis (16,17).…”

“…The quantitative determination of biotin in a variety of multivitamin/ multielement supplements has been successfully accomplished via affinity-binding methodology-solid-phase 125 I-avidin binding assay (16). However, the binding assay suffers from the need to use and dispose of a radioactive material ( 125 I), an inability to discriminate between biotin and biotin metabolites, and a lengthy (2-day) sample analysis (16,17). Quantification of biotin in multivitamin/multielement supplements has generally been approached via the application of physicochemical methods because of the need to separate trace levels (0.002% mass fraction) of biotin from other higher-level vitamins and elements (12).…”