A Solvatochromic Aluminum-1,8-Naphthalimide Complex 2D Nanostructure as a Versatile Probe for Sudan III Detection and Forensic Analysis

Abstract

This study focuses on the development of a 2D nanostructure-based aluminum complex with 1,8-naphthalimide (Al-Nap) that exhibits negative solvatochromism and bright green fluorescence, emitting around 500 nm when excited at 390 nm. The Al-Nap complex was applied for the detection of Sudan III dye, a potential Class III carcinogen still illegally used in cosmetics and food, with a detection limit of 11 nM and a linear range of 100 nM to 250 µM. The quenching of fluorescence is driven by a distinct interaction between Al-Nap NSs and Sudan III, primarily due to the Inner Filter Effect (IFE) followed by the reduction of Sudan III. Importantly, the Al-Nap complex also functions as a reductase, catalyzing the Sudan III into its reduced form, which further enhances the quenching effect. This dual functionality not only facilitates highly sensitive detection but also underscores the versatility of the Al-Nap complex in chemical sensing. Additionally, the derived fluorescent powder shows promise in latent fingerprint detection, highlighting its potential for advanced fluorescence-based sensors in both chemical sensing and forensic analysis.