ABSTRACT
Trans-resveratrol (t-RESV) is an important and natural polyphenolic antioxidant generally found in grapes and in its derivatives such as red wine and grape juices. The t-RESV has been explored in the pharmaceutical industry for its anti-inflammatory, anti-cancer, and neuroprotective properties. The t-RESV electrochemical determination has basically been carried out using modified electrodes-based sensors. Although these devices show good analytical performance, the electrode preparation can be laborious, and the devices may lack reproducibility. In this sense, it was proposed here a new methodology for the t-RESV electrochemical detection using unmodified screen-printed electrodes and differential pulse voltammetry (DPV). The response of the anodic signal has optimized varying the most important parameters of DPV (pulse time, pulse potential, and pulse step) using the response surface methodology. We showed based on analysis of variance that the new mathematical model developed can predict responses for the t-RESV using DPV. Furthermore, the new analytical method was validated from the limits of detection and quantification. We have still shown that t-RESV can be quantified in commercial drug using DPV with the optimized parameters. The selectivity test also showed that the sensor can be used to determine the antioxidant in other more complex matrices. Additionally, the proposed electrochemical system is completely portable and can work with its own energy, which facilitates point-of-care analysis.
Subject(s)
Resveratrol , Electrodes , Limit of Detection , Reproducibility of ResultsABSTRACT
Microfluidic devices that generate stable concentration gradients are efficient instruments for automated calibration for analytical and bioanalytical systems. However, little attention has been paid to the development of reusable microfluidic concentration gradient generators, which can be useful for a range of species through mathematical characterization. In this work, we develop a microfluidic device based on three steps of serial dilution that were able to generate nonlinear concentration gradient for dyes and biomolecules. The microfluidic device was described mathematically, statistically and was suitable for reusable analytical and bioanalytical analysis. The device reproducibility was assessed by experimental tests, which have shown the same gradient concentration profile for different dyes and statistical reproducibility with 95% confidence interval for bovine serum albumin (BSA). Moreover, the experimental data converged well with those obtained by computational fluid dynamics simulation. Applicability was verified by coupling the microfluidic device to a surface plasmon resonance (SPR) biosensor, based on nanohole arrays with sensitivity of 358.7 nm RIU-1 determined by white-light SPR excitation exposed to different D-(+)-glucose aqueous solutions with 1.3361-1.4035 refractive index interval. The transmission light intensities obtained by the array of images allowed to quantify a pseudo-unknown BSA sample (160 µg mL-1) at 138 µg mL-1. The SPR analysis has been validated in parallel by fluorescence emissions, which showed a concentration of 154.8 ± 16.6 µg mL-1.
