This study aimed to develop a methodology for simultaneous quantification of quercetin, myricetin, and ellagic acid in ultrasound-assisted (UAE) and pressurized liquid (PLE) extracts of lyophilized camu-camu, using HPLC-DAD. The extracts UAE (water as solvent, solvent-to-solid ratio of 22 mL g−1, 35 °C, and 20 min) and PLE (ethanol as solvent, solvent-to-solid ratio of 22 mL g−1, 80 bar, 35 °C, 7 mL min−1) were chromatographed on a Shimadzu LC-2030 C 3D HPLC column with 70% methanol in water (v/v) as mobile phase and visualized via a diode array detector. For all the samples, the purity angle values were lower than their corresponding purity limits, confirming that the method was specific for the determination of quercetin, myricetin, and ellagic acid. For these compounds, the linearity was greater than 0.99, indicating that the model was suitable for quantifying concentrations. The limits of quantification were 129, 262, and 122 262 µg·mL−1 for quercetin, myricetin, and ellagic acid, demonstrating that the method was suitable for the quantitative determination. All relative standard deviation results were within expected values, showing intermediate precision of up to 8.0% between the first and second day, up to 5.3% between repetitions, and variability of 90 to 107% between analyses performed on different days. Finally, the extracts presented a concentration range of 5.99 and 14.56 mg 100 g−1 for quercetin, 19.61 and 34.87 mg 100 g−1 for myricetin, and 87.47 and 147.65 mg 100 g−1 for ellagic acid. Therefore, the methodology has adequate accuracy, precision, and robustness for the quantification of quercetin, myricetin, and ellagic acid.
Pereira et al. (Tue,) studied this question.