Non-Anthocyanin Phenolic Compounds in Açaí (Euterpe oleracea Mart.) Juice by Ultrahigh-Performance Liquid Chromatography-Diode Array Detector (UHPLC-DAD): A Multivariate Optimization.

Currently available high-performance liquid chromatographic (HPLC) methods for the analysis of non-anthocyanin compounds in açaí are time-consuming or employ complex and costly detection systems. Therefore, we hypothesized that by using ultrahigh-performance liquid chromatography interfaced with a diode array detector (UHPLC-DAD) in conjunction with multivariate optimization tools (response surface methodology, Derringer and Suich desirability) would give a simple, fast, effective and reliable method to determine eight phenolic acids and four flavonoids in açaí juice. Three independent variables were assessed: initial acetonitrile (ACN) concentration in the gradient elution, final ACN concentration at the end of the gradient and the linear time of the gradient elution. Resolution between peaks was assessed as a response. The optimum chromatographic conditions were initial and final ACN concentrations: 7.8-15.7% in 8 min. The method showed to be suitable for quantification. Moreover, it was successfully applied for the analysis of non-anthocyanin compounds in three commercial açaí juice samples. Therefore, UHPLC and multivariate optimization tools are powerful to decrease method development time and to give faster separations. In the medium term, our method will result in reducing costs of analysis, while lowering the generation of toxic wastes.