“…Since the last few years, nanoparticle-based sensors have undergone rapid development as compared with molecular probes because of their stable fluorescence property, excellent sensitivity, and selectivity . For these purposes, different types of fluorescent nanoparticles such as carbon dots (CDs), ,,, N-doped CDs, − N/P codoped carbon dots, B/N codoped CDs, N/S-doped CDs, N/S codoped CDs, 2,2′-(ethylenedioxy)-bis(ethylamine)-functionalized carbon nanorods (CNRs), fluorescein/poly(ethylenimine)-modified reduced graphene oxide, mercaptosuccinic acid-functionalized gold nanoparticles (AuNPs), glycol chitosen-functionalized AuNPs, p -amino salicylic acid dithiocarbamate-functionalized AuNPs, N -acetyl- l -cysteine silver nanoparticles (AgNPs), l -cysteine-capped Fe 3 O 4 @ZnO, 3,3,′5,5′-tetramethylbenzidine-functionalized upconversion nanoparticles (UCNPs), and self-assembly-based fluorescent organic nanoparticles have been designed to allow the fluorometric detection of the Fe 3+ metal ions . In addition, fluorescent organic molecule-based colorimetric sensors have also been developed for Fe 3+ metal ion sensing, such as rhodamine 6G derivative-based fluorescent probes and Schiff base ligand-based sensors. , Moreover, Schiff base ligand-coated AuNPs have been developed for Fe 3+ metal ion sensing .…”