Determination of the total cadmium, copper, lead and zinc concentrations and their labile species fraction in apple beverages by flow-through anodic stripping chronopotentiometry

•Flow-through system application to simultaneously determine Cd, Cu, Pb and Zn.•ASCP method development to asses the labile metals fraction in apple beverages.•Measurement conditions optimization and validation for direct analysis of samples.•ASCP method reliability to determine the bioavailable fraction of Cd, Cu, Pb and Zn.

An analytical procedure for operationally defined speciation of Cd, Cu, Pb and Zn in apple beverages by anodic stripping chronopotentiometry (ASCP) is presented. Optimal measurement conditions were set down to reliably determine the fraction of the labile metals species. The mean total concentrations of Cu, Pb and Zn were 69 ± 20, 7.3 ± 3.3, and 129 ± 59 μg L−1 in apple juices, and 18 ± 3, 4.2 ± 0.1, 53 ± 5 μg L−1 in apple drinks, respectively. The contributions of the fraction of the ASCP-labile species varied from 43 to 63% (Cu), from 32 to 42% (Pb) and from 38 to 58% (Zn). The Cd content in all analyzed samples was below 0.02 μg L−1. The detection limits (DLs) achieved for Cu, Pb and Zn were 0.04 μg L−1 (Cu), 0.02 μg L−1 (Pb), and 0.10 μg L−1 (Zn).