# Environmentally benign carbon nano dots as luminescence probe for quantification of palladium (II) chloride impurity in naproxen

## TL;DR

This paper introduces eco-friendly carbon dots made from garlic peels to detect harmful palladium impurities in naproxen drugs.

## Contribution

The novelty lies in using garlic peel-derived carbon dots with multiple active chromophores for green sensing of palladium in naproxen.

## Key findings

- Carbon dots effectively detect palladium chloride in naproxen via fluorescence quenching.
- The method is linear and accurate within 0.0088–0.8870 µg/mL palladium chloride range.
- The technique complies with ICH guidelines for drug impurity validation.

## Abstract

Green shades of “The 2030 Global Green Agenda” have directed the analysts into a peaceful relationship with surrounding environment. Natural resources, clean energy, green solvents are in commitment with Earth’s sustainability. Hazardous inorganic chemical reagents are in gradual replacement by nanoscale reactive species of green origins. In this sense, the present study utilizes nano Carbon Dots, synthesized from garlic peels as natural precursor, with a modified surface activity “multiple active chromophores”. The latter act as potent fluorogenic scavengers for optical nano sensing of Palladium traces in the anti-inflammatory Naproxen drug substance. Palladium traces are found in Naproxen bulk as synthesis-related impurity. Higher ingested levels increase the risk of debilitating diseases in the human body. Stoichiometric reaction between Palladium traces and the dots’ active surfaces was quantified indirectly along the linear spectral diminish of carbon dots luminescence. The proposed methods involve quantitative fluorescence quenching of carbon dots at 432 nm upon excitation at 375 nm and absorption peak at 250 nm upon addition of studied palladium chloride. The obtained results were in good agreement according to the Stern-Volmer equation along the linear range of 0.0088–0.8870 µgmL-1 palladium chloride. The developed procedures were validated as per ICH guidelines.

The online version contains supplementary material available at 10.1186/s13065-025-01600-4.

The online version contains supplementary material available at 10.1186/s13065-025-01600-4.