Fluorescence-Digital Image Based with emission reflectance area detection: a new approach of data in digital images for chemical analysis

A new approach using emission reflectance area detection (ERAD) from fluorescence digital image-based methods, called FDIB-ERAD, has been described for the first time to determine analytes. This approach was discovered with new portable equipment built by 3D printing, with excitation in the ultraviolet to visible region (from 300 to 800 nm) and detectability similar to that of a commercial spectrofluorometer. The FDIB-ERAD method achieved a linear relationship between the signal and concentration by employing emission analytes across the entire visible spectrum using quinine (QN), rhodamine 6G (RDA-6G), rhodamine B (RDA-B), and 4-Dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). This method overcomes the limitations of using RGB color model values. The working range obtained with FDIB-ERAD was greater than that observed with the classical approach using color values as the analytical signal. The concentration range obtained for QN was from 50 ng mL⁻¹ to 1000 ng mL⁻¹, with a detection limit of 10 ng mL⁻¹ and a linear regression with an R² of 0.998. Thus, the accuracy, precision, reproducibility, and sensitivity were validated by measuring QN in commercial samples. The FDIB-ERAD approach has been efficiently employed in other literature articles, and the limitations of the classical approach have been overcome. Therefore, understanding ERAD allows for the planning and development of new tools to achieve advantages, such as increased sensitivity and dynamic range.