Smartphone‐Assisted Visual and Fluorometric Detection of Meloxicam Using Fluorescent Carbon Quantum Dots With Greenness Assessment

ABSTRACT Designing a simple, reliable, sensitive, and low‐cost probe for the detection of meloxicam (MLX) is of great importance for ensuring effective pharmaceutical quality control and environmental monitoring. This study presents a rapid, sensitive, and eco‐friendly method for the quantification of MLX using fluorescent carbon quantum dots (CQDs) synthesized through a green and cost‐effective approach. The prepared CQDs exhibited excellent fluorescence stability, uniform size distribution, high water dispersibility, and remarkable sensitivity toward MLX, enabling efficient and accurate detection. Comprehensive spectroscopic and microscopic characterization confirmed their nanoscale morphology and stable luminescent properties. Under optimized conditions, the CQDs demonstrated a pronounced fluorescence quenching effect upon interaction with MLX, forming the basis for both fluorometric and smartphone‐assisted detection. The developed smartphone‐based platform exhibited a linear response over the concentration range of 0.0–190.2 µM with a detection limit of 2.5 µM. The greenness of the proposed method was assessed using three evaluation tools, Analytical GREEnness Metric Approach, Analytical Eco‐Scale, and Green Analytical Procedure Index. Furthermore, Click Analytical Chemistry Index and Blue Applicability Grade Index were also applied in this work. Thus, the corresponding pictograms confirmed that the developed method is environmentally benign, posing minimal risks to human health and the environment.