Solid‐Phase Extraction of Pb 2+ on Multicomponent Oxide Coupled to Portable 3D‐Printed Electrochemical Microcell Using Boron‐Doped Diamond Electrode

In this article, a solid‐phase preconcentration method using the multicomponent oxide SiO 2 /TiO 2 /Sb 2 O 5 as a chelating agent‐free solid‐phase extractor for the determination of Pb 2+ at trace levels, employing a portable 3D‐printed electrochemical cell, was developed. The optimization of the preconcentration parameters was carried out using a 2 4–1 fractional factorial design. The most effective conditions were pH 5.0, elution volume 600 µL, eluent (H 2 SO 4 ) concentration 1.5 mol L −1 , and preconcentration flow rate 6.0 mL min −1 of 20.0 mL of the sample. Electrochemical parameters were also optimized, establishing ideal values for deposition time (60 s), deposition potential (–1.5 V), potential step (6 mV), pulse amplitude (60 mV), and frequency optimal (10 Hz). The developed method exhibited high precision and sensitivity, with limits of detection and quantification of 0.98 and 3.30 µg L −1 , respectively, and showed tolerance to different metal ions (Ca 2+ , Mg 2+ , Ni 2+, and Co 2+ ). When applied to real samples, such as mineral and tap water, as well as Korean ginseng, the method demonstrated satisfactory recovery values (90%–108%), attesting to the method's applicability and accuracy without interference.