An activatable chemiluminescent probe for selective and portable quantification of copper ions in food and environmental samples

Copper ion (Cu 2+ ) quantification in complex food and environmental matrices remains challenging because of matrix interference and the need for rapid, portable analysis. Herein, we report ACL-Cu, an activatable chemiluminescent 1,2-dioxetane probe for selective Cu 2+ detection. Under mildly alkaline conditions (pH 8.0), Cu 2+ triggers intramolecular cyclization of ACL-Cu, producing green chemiluminescence centered at ∼550 nm with an approximately 26-fold signal enhancement relative to the probe alone. ACL-Cu showed high selectivity toward Cu 2+ over common metal ions and anions, and quantitative analysis on the IVIS platform gave a linear response over 0.2–3.0 μM with a limit of detection of 43 nM. A handheld portable device also enabled Cu 2+ quantification over the same linear range, with a detection limit of 76 nM and an assay time of ≤10 min. In porcine liver and lake water samples spiked prior to pretreatment, ACL-Cu provided concentration-dependent responses and accurate quantification, affording recoveries of 91.7–97.0% for IVIS and 90.0–96.0% for portable device, with relative standard deviations below 2.35%. These results demonstrate that ACL-Cu is a reliable chemiluminescent platform for Cu 2+ determination in complex real samples and holds promise for food safety and environmental monitoring.