title: Biotin determination in food supplements by an electrochemical magneto biosensor.
abstract: An electrochemical magneto biosensor for the rapid determination of biotin in food samples is reported. The affinity reaction was performed on streptavidin-modified magnetic microbeads as a solid support in a direct competitive format. The biotinylated horseradish peroxidase enzyme (biotin-HRP) competes with free biotin in the sample for the binding sites of streptavidin on the magnetic microbeads. The modified magnetic beads were then easily captured by a magneto graphite-epoxy composite electrode and the electrochemical signal was based on the enzymatic activity of the HRP enzyme under the addition of H(2)O(2) as the substrate and o-phenilendiamine as cosubstrate. The response was electrochemically detected by square wave voltammetry. The limit of detection was 8.4×10(-8) mol L(--1) of biotin (20 μg L(--1)) with a dynamic range from 0.94 to 2.4×10(-7) mol L(--1). Biotin-fortified commercial dietary supplement and infant formula samples were evaluated obtaining good performances in the results. Total time of analysis was 40 min per 20 assays.
authors: Laboratorio de Sensores y Biosensores, Cátedra de Química Analítica I, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina.
authors: Silvina V
authors: SV
authors: Kergaravat
authors: Gabriel A
authors: GA
authors: Gómez
authors: Silvia N
authors: SN
authors: Fabiano
authors: Tamara I
authors: TI
authors: Laube Chávez
authors: María I
authors: MI
authors: Pividori
authors: Silvia R
authors: SR
authors: Hernández
mesh_terms: D053000:Analytic Sample Preparation Methods; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000032:analysis* / Q000302:isolation & purification; D002138:Calibration; D019587:Dietary Supplements / Q000032:analysis*; D004563:Electrochemistry; D005504:Food Analysis; D041943:Infant Formula / Q000737:chemistry; D059346:Magnets / Q000737:chemistry*; D008863:Microspheres
chemical_list: D001710:Biotin