Resumen en inglés

This project evaluated the technical feasibility of a microanalytical coulometric titration system with on-line photocolorimetric coupling, with minimal instrumentation, with low-cost and accessible materials for the determination of ascorbic acid in artificial juice samples. To evaluate the simple and combined effects of the independent parameters [KNO3] and [KI], on the response variable time and optimization of the process conditions, a 32 factorial design was used with statistical analysis of response surface methodology (MSR). The method meets the acceptance criteria established by the AOAC and allows the determination of ascorbic acid in fruit juices with a detection limit of 0.001 M (176 mg L -1), precision expressed as a coefficient of variation of 1.7%, accuracy as recovery percentage of 97.6% and error of 1.6% and average combined uncertainty of 0.0002 in a working range of 0.001 to 0.01 M. The precision and accuracy results with respect to the redox titration reference method and different analysis methods reported as spectrophotometric , electroanalytical, digital colorimetry, fluorescence and chromatography, do not present statistically significant difference. The proposed method was simple, sensitive, precise, exact and very low instrumental costs and indicates that it can be useful for the routine determination of ascorbic acid as a quality control tool in various formulations.