Ultra performance liquid chromatograph

Phenolic untargeted metabolite profile was identified and quantified using a Waters Ultra-Performance Liquid Chromatograph (UPLC), fitted with a Waters Acquity Photodiode Array Detector (PDA) and linked to a Synapt G2 quadrupole time of flight mass spectrometer (Waters, Milford, MA, USA), as described by Managa et al. (15 (link)) and Ndou et al. (16 (link)), without any modifications. Phenolic compounds were extracted from freeze dried pumpkin leaves (50 mg) that underwent different blanching treatments by ultrasonication in 70% aqueous ethanol. Phenolic compounds from pumpkin leaves that underwent different blanching treatments were extracted using ultrasonication of 50 mg freeze-dried samples in 70% aqueous ethanol. Concentrations of the phenolic compounds were determined using the reference calibrants catechin (LOD 1.414333, LOQ 4.286), epicatechin (LOD 5.105, LOQ 15.469), and rutin (LOD 3,294; LOQ 9.981), to quantify compounds based on the areas of their extracted mass chromatograms. The respective calibration curves are given in Supplementary Figure 1.
The LOD and LOQ values for TargetLynx software processed the obtained data, as described previously by Managa et al. (15 (link)) and Ndou et al. (16 (link)), and the concentration of phenolic compounds was expressed as mg kg⁻¹.

The anthocyanins in Natal plum were identified using a method previously reported by Seke et al. [5 (link)] using a Waters ultra-performance liquid chromatograph (UPLC) (with a Water Acquity photodiode array detector (PDA), coupled to a Synapt G2 quadrupole time-of-flight (QTOF) mass spectrometer (MS) (Waters, Milford, MA, USA). The anthocyanins were identified after using an electrospray ion source operating with a cone voltage of 15 V, desolvation temperature of 275 °C and a desolvation gas flow at 650 L h⁻¹ in negative ESI mode. The mobile phases A was milliQ water containing 10% formic acid, and mobile phase B was acetonitrile containing 10% formic acid. The gradient was: 0–1.5 min, 0.5% B; 1.5–4 min, 0.5–11% B; 4–23 min, 11–15% B; 23–28 min, 15–100% B; 28–38 min, 100% B; 38–39 min, 100–0.5% B; 39–49 min, 0.5% B as reported by Ndou et al. (2019). Flow rate was set at 0.5 mL/min and column temperature was set at 50 °C. The anthocyanins and other phenolic compounds were quantified using standards and expressed as mg kg⁻¹. Supplementary Table S1 presents the regression equation, correlation coefficient (R²), limit of detection (LOD), limit of quantitation (LOQ) of phenolic compounds by UHPLC/Q-TOF-MS.