# Functionalized novel carbon dots from bell pepper seeds for sustainable green Edoxaban quantification

## TL;DR

Researchers made eco-friendly carbon dots from bell pepper seeds to detect a non-fluorescent drug, Edoxaban, using a sustainable and sensitive method.

## Contribution

Novel carbon dots from bell pepper seeds are used for the first time to quantify Edoxaban via fluorescence quenching.

## Key findings

- The carbon dots showed high sensitivity for Edoxaban detection with a low limit of detection (0.22–0.23 µg/mL).
- The method achieved good recovery rates (98.79–99.77%) when tested on commercial drug tablets.
- The synthesis and analytical methods were evaluated as environmentally friendly using green chemistry metrics.

## Abstract

Global warming and the developed worldwide awareness have persuaded efforts to minimize the generated hazardous wastes. As a result, “green” chemical procedures are being gradually included in science for sustainable development. This concept has been extended and inspired chemists to fabricate novel green carbon dots (CDs) from natural plants. Herein, we represent novel CDs synthesized by recycling seeds obtained from bell pepper as fluorescent probe for the determination of Edoxaban tosylate hydrate (EDO) a non-fluorescent drug; we exploit the advantage of the inner filter effect between the absorption peak of the drug and the emission peak of the CDs. This overlap resulted in quenching the fluorescence of CDs by increasing the concentration of EDO within the range 0.80–20.00 µg/mL with a limit of detection 0.23 and 0.22 µg/mL and a limit of quantitation 0.69 and 0.72 µg/mL for Microwave CDs and Plate CDs, respectively, at λex/λem 310/409 nm. Two facile preparation techniques for the CDs were used, the microwave-assisted method and the thermal decomposition method, using a single-step approach. The fabricated CDs were characterized using various techniques, including UV-vis, fluorescence and Fourier transform infrared spectroscopies, energy-dispersive X-ray, high-resolution transmission electron microscope, X-ray Diffaction, X-Ray photoelectron spectroscopy and zeta potential. The performance of the synthesized fluorescent probe for the determination of EDO was evaluated according to ICH guidelines. The accomplished results, together with the simplicity, sensitivity, and low cost of the developed probe, recommended its appropriateness for the routine quality control assay of EDO pharmaceutical formulation, as good % recovery was obtained upon the investigation of the marketed tablets with 99.77% and 98.79% recoveries for microwave CDs and plate CDs, respectively. The method’s greenness was evaluated using three integral matrices, the Blue Applicability Grade Index, the Complementary Green Analytical Procedure Index and Analytical Eco-Scale.

The online version contains supplementary material available at 10.1186/s13065-025-01427-z.

Fabrication of novel carbon dots (CDs) for recycled bell pepper seeds.Characterization of the synthesized CDs using various techniques including UV-vis and fluorescence spectroscopies, high-resolution transmission electron microscope, energy-dispersive X-ray, and Fourier transform infrared spectrometer.Developing a fluorescent probe for the determination of Edoxaban tosylate hydrate, a non-fluorescent drug, using the synthesized CDs.Comparing our results with previously published papers to illustrate the significance of our work.Greenness assessment of the synthesis and the analytical methods using three integral matrices, the Blue Applicability Grade Index (BAGI), the Complementary Green Analytical Procedure Index (Complex-GAPI), and The Eco-Scale.

Fabrication of novel carbon dots (CDs) for recycled bell pepper seeds.

Characterization of the synthesized CDs using various techniques including UV-vis and fluorescence spectroscopies, high-resolution transmission electron microscope, energy-dispersive X-ray, and Fourier transform infrared spectrometer.

Developing a fluorescent probe for the determination of Edoxaban tosylate hydrate, a non-fluorescent drug, using the synthesized CDs.

Comparing our results with previously published papers to illustrate the significance of our work.

Greenness assessment of the synthesis and the analytical methods using three integral matrices, the Blue Applicability Grade Index (BAGI), the Complementary Green Analytical Procedure Index (Complex-GAPI), and The Eco-Scale.

The online version contains supplementary material available at 10.1186/s13065-025-01427-z.