Electrochemical Determination of Chromium(VI) with Au/UiO-66 Modified Glassy Carbon and Screen-Printed Electrodes by Linear Sweep Voltammetry (LSV).

The development of rapid methods for in situ chromium determination in natural water is important. A new nanocomposite was fabricated by impregnating gold nanoparticles onto archetypical UiO-66 metal organic frameworks and modifying glassy carbon electrodes (Au/UiO-66/GCE) for rapid Cr(VI) determination in water by linear scanning voltammetry (LSV). The Au/UiO-66/GCE showed excellent linearity in the 100 to 1200 ppb Cr(VI) concentration range, with 0.07132 µA/ppb·cm² sensitivity and a 11.73 ppb detection limit. When potential interfering metals were added, including Cr(III) and Fe(III), the electrochemical detection signal of Cr(VI) did not meaningfully change, suggesting that Au/UiO-66/GCE has good selectivity. A Au/UiO-66/screen printing sensor was also developed for Cr(VI) and used with a portable, handheld electro-analyzer. The Au/UiO-66 nanocomposite—used as an active substrate for electrode modification—was stable, interference-free, and fast, showing promise for the practical determination of Cr(VI) species. [ABSTRACT FROM AUTHOR]