Simple and eco-friendly synthesis of crude orange-peel-derived carbon nanoparticles for detection of Fe and ascorbic acid.

Although fluorescence sensors based on carbon dots (CDs) have been developed widely, multicomponent detection using CDs without extra and tedious surface modification remains a challenge. Here, the crude carbon nanoparticles (CPs) as a fluorescence sensor were prepared through one-pot hydrothermal process using orange peel as the precursor. The method was simple, rapid, economical, and eco-friendly given that such extra steps as dialysis and lyophilization were not required. By adding ethanol into the reaction solvent, the fluorescence properties of orange-peel-derived CPs as well as their sensitivity of detecting Fe with a limit of detection of 0.25 μM were improved. Additionally, orange-peel-derived CPs could be used as a fluorescence sensor for detection of ascorbic acid (AA) with a LOD of 5 μM. More importantly, the proposed fluorescence methods were successfully used to qualitatively and quantitatively analyze Fe and AA in real samples. Recovery of Fe from tap water was within the range 97.2-105.4%. Conversely, recovery of AA from vitamin C tablets and orange juices laid within the ranges 97.7-99.3% and 93.2-97.6%, respectively.