BACKGROUND: Riboflavin (vitamin B₂), as the exclusive source for the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in humans, is a water-soluble vitamin critical for metabolism and energy production. In its coenzyme forms, riboflavin is involved in essential oxidation-reduction reactions. Deficiency leads to skin and mucosal disorders. Measurement of plasma riboflavin can be used to assess vitamin B₂ status in at-risk individuals. METHODS: Proteins are removed from plasma by acid precipitation. An aliquot of the resulting supernatant is analyzed by reversed-phase HPLC. Impurities are separated from riboflavin isocratically and the target material is detected fluorometrically (excitation 450 nm; emission 520 nm). RESULTS: The method was validated for linearity, limit of quantification, accuracy, precision, and interference. The method was accurate and correlated well (R² = 0.993) to expected concentrations of spiked pooled plasma samples. Imprecision was < 10%. Riboflavin concentrations were determined in samples obtained from self-reported healthy adults who were not taking vitamin supplements. The reference interval established by nonparametric analysis was 6.7-50.1 nmol/l. CONCLUSIONS: This HPLC method allows separation and measurement of riboflavin in plasma in 7 min. Results from the assay may be used for clinical diagnosis of deficiency and to monitor therapeutic vitamin supplementation regimes.
BACKGROUND:Riboflavin (vitamin B₂), as the exclusive source for the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in humans, is a water-soluble vitamin critical for metabolism and energy production. In its coenzyme forms, riboflavin is involved in essential oxidation-reduction reactions. Deficiency leads to skin and mucosal disorders. Measurement of plasma riboflavin can be used to assess vitamin B₂ status in at-risk individuals. METHODS: Proteins are removed from plasma by acid precipitation. An aliquot of the resulting supernatant is analyzed by reversed-phase HPLC. Impurities are separated from riboflavin isocratically and the target material is detected fluorometrically (excitation 450 nm; emission 520 nm). RESULTS: The method was validated for linearity, limit of quantification, accuracy, precision, and interference. The method was accurate and correlated well (R² = 0.993) to expected concentrations of spiked pooled plasma samples. Imprecision was < 10%. Riboflavin concentrations were determined in samples obtained from self-reported healthy adults who were not taking vitamin supplements. The reference interval established by nonparametric analysis was 6.7-50.1 nmol/l. CONCLUSIONS: This HPLC method allows separation and measurement of riboflavin in plasma in 7 min. Results from the assay may be used for clinical diagnosis of deficiency and to monitor therapeutic vitamin supplementation regimes.