UiO-66-NH2@tannic acid-assisted solid-phase extraction combined with laser-induced breakdown spectroscopy for sensitive detection of Pb (II) in aquatic products

Abstract

In this work, a novel method for sensitive detecting heavy metal Pb (II) in aquatic products was developed using UiO-66-NH₂@tannic acid (UiO-66-NH₂@TA) solid-phase extraction combined with laser-induced breakdown spectroscopy (LIBS). UiO-66-NH₂@TA adsorbent could effectively extract Pb (II) from the digestive solution of aquatic products. Characterization of the morphology of the adsorbent was performed using transmission electron microscopy and scanning electron microscopy. The optimal experimental conditions for LIBS detection, including sample preparation, substrate type, laser energy, and delay time, were investigated. The results showed that the strongest Pb I 405.7 nm spectral signal can be obtained by dripping UiO-66-NH₂@TA adsorbent onto a silicon wafer for LIBS testing. The limit of detection and limit of quantification for Pb (II) in aqueous solution were 0.18 μg/mL and 0.61 μg/mL, respectively. The calibration curve demonstrated good sensitivity and accuracy for Pb (II) detection with a correlation coefficient of 0.9905. Spiked recovery experiments on large yellow croakers and scallops yielded recovery rates of 75.25 % - 99.08 %, which was consistent with the results from atomic absorption spectrometry. This study underscores the potential of the solid-phase extraction combined with laser-induced breakdown spectroscopy for practical application in food safety monitoring, demonstrating its effectiveness and reliability in detecting Pb (II) in aquatic products.