Eco-friendly cobalt-doped carbon quantum dots for spectrofluorometric determination of pregabalin in pharmaceutical capsules

Abstract

The misuse of pregabalin has become a significant issue over the last decade. Consequently, there is a growing demand for a sensitive and selective method for its determination. In this study, an eco-friendly cobalt-doped carbon quantum dots (CQDs) have been fabricated and applied as nanoprobes for the fluorometric determination of pregabalin. The CQDs were synthesized through mixed doping with non-metallic atoms such as nitrogen and sulfur, and a metal ion, cobaltous ion, via a microwave-assisted method in just 1.5 min. The synthesized Co-NS-CQDs exhibited advantageous characteristics, including rapid response times, compatibility with various pH levels, exceptional detection limits, high sensitivity, and excellent selectivity. The Co-NS-CQDs exhibited a high quantum yield (55 %) relative to NS-CQDs (38 %), with blue emissive light at 438 nm. The assessment of pregabalin was based on its enhancement effect on the native fluorescence intensity of CQDs. The proposed method had a good linearity over the range of 25–250 µg/mL, with a limit of detection of 4.17 µg/mL and a limit of quantitation of 12.63 µg/mL, respectively. The prepared NS-CQDs have been successfully applied for the pregabalin determination in pharmaceutical capsules, with excellent % recovery (98–102 %). The greenness of the developed method has been investigated using different greenness metrics, in comparison with the reported RP HPLC method. The greenness characteristics of the method originated from the synthesis of CQDs, utilizing sustainable, readily available, and cost-effective starting materials.