Multivariate optimisation and validation of a capillary electrophoresis method for the analysis of resveratrol in a nutraceutical

A rapid and simple method based on capillary electrophoresis was developed for the quality control of nutraceuticals containing resveratrol. Setting the UV detector at 280 nm, the optimisation involved the separation of 11 effervescent tablet components, including the active compounds vitamin C, vitamin B2, flavanones and hydroxycinnamic acids. Flufenamic acid was employed as internal standard. The effects of background electrolyte concentration, acetonitrile percentage and voltage were investigated by means of response surface methodology, considering as responses the critical resolution values and analysis time. The optimum conditions were found by Derringer desirability function. The background electrolyte consisted of 23 mM borate buffer, adjusted to pH 10.0 with 1 M sodium hydroxide, containing 7% (v/v) acetonitrile. Temperature and voltage were set at 25 °C and 26 kV, respectively. Applying these conditions, the analysis time was below 7 min. The performances of the method were tested in terms of selectivity, robustness, linearity and range, accuracy and precision and system suitability, following ICH guidelines.