title: Total polyphenols content in white wines on a microfluidic flow injection analyzer with embedded optical fibers.
abstract: Absorbance detection in food microdevices has not been thoroughly used due to low levels of sensitivity in measurements. Thus, it is necessary to develop microfluidic methods for improving photometric detection. For this purpose, a simple coupled-optical-fiber-polydimethylsiloxane (PDMS) microdevice was developed, to quantify polyphenols content in white wine employing the Folin-Ciocalteu reaction method. A 6V and 10W halogen lamp with an optical path length of 7mm between optical fibers, which were placed into the microchip, using guides at the outlet of the flow, increased the level of sensitivity during detection. The linear range was from 0.03mmol/L to 0.18mmol/L. Thus, the corresponding equation was: Abs=4.00(±0.16) [tannic acid]+0.17(±0.017). Intra-laboratory repeatability and reproducibility percentages were 2.95% and 6.84%, respectively. Such results were compared to those obtained from applying the conventional flow-injection analysis method, based on the same type of reaction. The relative error between methods was less than 13%.
authors.affiliation: Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
authors.forename: Sandoval-Ventura
authors.initials: SV
authors.lastname: Oscar
authors.affiliation: Laboratorio de Biofisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
authors.forename: Olguín-Contreras Luis
authors.initials: OL
authors.lastname: Fernando
authors.affiliation: Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico. Electronic address: pilarm@unam.mx.
authors.forename: Cañizares-Macías María
authors.initials: CM
authors.lastname: Del Pilar
mesh_terms: D017022:Flow Injection Analysis / Q000379:methods / Q000592:standards; D056656:Lab-On-A-Chip Devices / Q000592:standards*; D044085:Microfluidics / Q000379:methods / Q000592:standards*; D055100:Optical Fibers / Q000592:standards*; D059808:Polyphenols / Q000032:analysis*; D015203:Reproducibility of Results; D014920:Wine / Q000032:analysis*
chemical_list: D059808:Polyphenols
keywords: Folin-Ciocalteu; Microfluidics; Optical fibers; Polyphenols; Spectrophotometry; Wine