Leaf-like ZIF-on-ZIF-derived heterostructures enable portable electrochemical determination of rutin in fruits

Leaf-like ZIF-on-ZIF derived CNTs-reinforced Co–N-doped carbon heterostructure (CoCN-CNTs) was prepared. • CoCN-CNTs modified screen-printed carbon electrode was applied to sensitive rutin detection. • Linear detection range (0.1 to 120.0 μmol L −1 ) and the detection limit (0.033 μmol L −1 ) for rutin were realized. Rutin (RU) is an important dietary flavonoid with numerous health benefits, underscoring the need for rapid, reliable methods to quantify its content in food products. In this study, a portable electrochemical sensor for RU detection was developed using a two-dimensional zeolitic imidazolate framework (ZIF)-on-ZIF derived heterostructure. A leaf-like ZIF (ZIF-L) and cobalt-based ZIF (ZIF-67) precursor, denoted as ZIF-L@ZIF-67, was synthesized and pyrolyzed to form a carbon nanotubes (CNTs) reinforced Co–N-doped carbon heterostructure (CoCN-CNTs). The resulting material was immobilized on a screen-printed carbon electrode and applied to RU detection by differential pulse voltammetry. Owing to its high surface area and abundant Co−N active sites, CoCN-CNTs exhibited excellent electrochemical activity and sensitivity. The modified electrode showed a wide linear response range of 0.1–120.0 μmol L −1 and a low detection limit of 0.033 μmol L −1 for RU. The sensor was successfully applied to the analysis of various fruit samples, achieving satisfactory recoveries and demonstrating strong potential for practical nutritional analysis. This work offers an effective strategy for designing high-activity two-dimensional ZIF-on-ZIF-derived heterostructures for portable electrochemical sensing applications. Download: Download high-res image (116KB) Download: Download full-size image