Determination of phenolic compounds and antioxidant activity in passion fruit pulp (Passiflora spp.) using a modified QuEChERS method and UHPLC-MS/MS

Abstract

A new method based on the modified QuEChERS approach was developed for determination of phenolic compounds in passion fruit pulp (Passiflora spp.) using UHPLC-MS/MS. Studies of extraction/partitioning and clean-up were carried out using different variations of the QuEChERS method (original, acetate, and citrate) and clean-up sorbents (PSA, GCB, C18 and Oasis® HLB). The original QuEChERS method with 25 mg of C18 as dispersive cleaning sorbent showed the best results for the proposed phenolic compounds (quercetin, rutin, 4-hydroxybenzoic, chlorogenic, ferulic, vanillic, caffeic, trans-cinammic, and p-coumaric acids). Under the optimized conditions, validation presented acceptable results for linearity (r2 ≥ 0.99), precision (RSD≤20%), recovery (73–115%), and the limits of quantification (4–80 μg/kg). The method developed was successfully applied to different species, including Passiflora edulis, Passiflora alata, and Passiflora ligularis. P. edulis was the only species that contained all target phenolic compounds, with the highest abundance of vanillic acid (426 ± 29 μg/kg) and quercetin (416 ± 6 μg/kg). In P. alata and P. ligularis species, rutin (289 ± 6 μg/kg) and caffeic acid (64 ± 2 μg/kg), respectively, were found at the highest levels. In addition, total phenolic content and antioxidant activity assays (DPPH radical and ABTS cation radical assays) correlated with the UHPLC-MS/MS analysis for all passion fruit pulps analyzed.