Multivariable optimization of ultrasound-assisted solvent extraction of bee pollen prior to its element analysis by FAAS

Abstract

A new method for determining total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee-collected pollen by line source-flame atomic absorption spectrometry (LS-FAAS) combined with ultrasound-assisted solvent extraction (UAE) at a sample preparation stage was developed. A Box-Behnken response surface design along with individual and composite desirability functions were applied to establish optimal conditions of the UAE procedure. Under optimal conditions, i.e., sonication of samples with a 1.1 mol L−1 HNO3 solution at 40 °C and for 15 min (for Ca, Cu, Mg, Mn and Zn) or a 0.9 mol L−1 HNO3 solution at 65 °C and for 15 min as well (for Fe), the method was verified to be precise (related standard deviations within 2–4%) and true (relative errors from −5% to +4%). Limits of detection (LODs) of studied metals were within the μg g−1 range. The developed method was used in very fast and simple analysis of ten different dried bee pollens collected in the summer of 2019.