Comprehensive investigation of Prunus armeniaca for natural green synthesis of carbon quantum dots; Applications as fluorescent nano-probes for ramipril.

The use of natural precursors for green synthesis of carbon quantum dots (CQDs) is attracting significant attention. However, concerns regarding the characters and performance of CQDs derived from the same natural resource can be raised. In the proposed research, Prunus armeniaca (apricots) juice was utilized as a natural precursor for CQDs through a single-step microwave-assisted method at 700 W for 5 min. The obtained CQDs were characterized and then assessed against those few that had been reported from apricots from different geographical and botanical origins. The developed CQDs showed excitation-dependent photoluminescent characters with red-shift emission (430-510 nm). The greener and cost-effective synthesis pathway had a higher quantum yield (37.1 %), with nano-sized CQDs (≈2.8 nm), and chemical composition of C (44.79 %), O (38.29 %), and N (16.92 %). The developed nanoprobes were then investigated for determination of ramipril (RAL) antihypertensive drug for the first time using this tool. They were found selective and sensitive for RAL determination in bulk powders and biological plasma within the range of 2.0-100.0 ng mL, where the limits of detection and quantification were 0.58 and 1.76 ng mL. The incorporation of RAL led to a notable decrease in the luminescence response of the synthesized green and stable CQDs at 505 nm (excitation 460 nm). Furthermore, the storage stability (in refrigerator) and reusability of the proposed CQDs were effectively confirmed for RAL analysis for 10 weeks. The proposed tool was finally compared to some other reported techniques and was found to be more efficient and cost-effective.