Dual-mode colorimetric and fluorescence sensing system for the detection of captopril based on Fe/NC nanozymes and carbon dots

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2022-12, Vol.282, p.121683, Article 121683
• Main Authors: Wu, Maolin, Lv, Yuntai, Lin, Zihan
• Format: Article
• Language: English
• Subjects: Captopril; Carbon dots; Colorimetric; Dual-mode; Fe/NC nanozymes; Fluorescence
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2022.121683

A high sensitive and selective dual-mode sensor for colorimetric and fluorescent detection of CP in pharmaceutical formulations. [Display omitted] •The peroxidase-like activity of Fe/NC NZs has been demonstrated.•Fluorescence and colorimetry determination of CP was proposed with composite system of Fe/NC NZs/H2O2/TMB/O-CDs.•Detection of CP in pharmaceutical formulations by the dual-mode sensor with satisfying results.•This method exhibited good analytical performance and high reliability. Metal nitrogen-doped carbon (MNC) nanozymes have received increasing attention in bio-catalysis filed due to adequate catalytic activity, outstanding stability and reusability. Herein, the Fe/NC nanozymes (Fe/NC NZs) with peroxidase-like activity was successfully synthesized and a fluorescence turn on and colorimetric dual-mode sensing system was developed for quantification of captopril (CP) based on Fe/NC NZs and orange-emitting carbon dots (O-CDs). The Fe/NC NZs as an enzyme mimic can efficiently catalyze the 3,3′,5,5′-tetramethylbenzidine (TMB) chromogenic reaction, forming blue-colored oxidized TMB product (oxTMB) with the presence of H2O2, leading to the fluorescence quenching of O-CDs simultaneously via the inner filter effect (IFE). When CP was present, the blue oxTMB was reduced to colorless TMB, resulting in the inhibition of IFE and the recovery of fluorescence of O-CDs. The fluorescence increase of O-CDs and absorbance decrease of oxTMB depended on CP concentration. Good linear relationships of fluorescence and colorimetric sensing towards CP were obtained in the range from 1 to 50 μM, and the detection limits were 0.47 and 0.56 μM, respectively. Moreover, this as-constructed dual-mode sensor was used to detect CP in pharmaceutical products with satisfactory results.