Preparation Of Doped Carbon Dots And Their Applications In Metal Ion And Drug Detection

As an emerging carbon nanomaterial,carbon dots（CDs）have attracted much attention due to their unique fluorescence properties,simple synthesis,excellent biocompatibility and high fluorescence stability.These advantages make them to be widely recognized and applied in environmental monitoring,biological imaging,ion detection and other fields.Based on these,two kinds of the metal and non-metal doped CDs were synthesized by one-step hydrothermal treatment of different reaction precursors,which were detailedly characterized by the modern analysis methods and were applied in the analytical detection of Sn（II）and vitamin B₂.The contents are as follows:Chapter 1:The structure,properties,preparation methods and application status of the fluorescent CDs were summarized.In addition,the research status of the doped CDs,the research background,content and innovation of this paper are summarized.Chapter 2:Multi-element Mn,N,Cl doped carbon dots(Mn,N,Cl-CDs,λ_ex=485 nm,λ_em=614 nm)emitting orange fluorescence were synthesized by one-step hydrothermal method using p-phenylenediamine as carbon source and anhydrous Mn Cl₂ as dopant.Mn,N,Cl-CDs were characterized by elemental analysis,transmission electron microscopy,ultraviolet spectroscopy,fluorescence spectroscopy,X-ray photoelectron spectroscopy,zeta potential,thermogravimetric analysis,fluorescence lifetime and inductively coupled plasma spectroscopy.A fluorescent probe for the detection of Sn（II）was constructed.Results show that Sn（II）can strongly quenched the fluorescence of Mn,N,Cl-CDs with of the linear range of 0.98～18.99 n M and 19.96～34.39n M and the detection limit of 0.677 n M.The method was applied to the determination of Sn（II）in environmental water samples with the recoveries of95.0%～105%,showing this probe has good reproducibility.Therefore,Mn,N,Cl-CDs is expected to be applied to the trace detection of Sn（II）in actual samples.Chapter 3:Yellow fluorescence Gd and N co-doped CDs(Gd,N-CDs,λ_ex=382 nm,λ_em=546 nm)were prepared using p-phenylenediamine as carbon source and Gd（NO₃）₃·6H₂O as dopant.Modern analysis methods（atomic force microscopy,elemental analysis,transmission electron microscopy,ultraviolet spectrum,fluorescence spectrum,etc.）were used to characterize the Gd,N-CDs.The results show that the shape of the Gd,N-CDs is regular with the average size of 3.22 nm.When vitamin B₂ was added into the Gd,N-CDs,the fluorescence of the Gd,N-CDs was significantly enhanced,so the Gd,N-CDs can be used as a fluorescent probe for the detection of vitamin B₂.The linear range of the Gd,N-CDs was 0.0063～3.8322μM and 4.5098～29.1323μM with the detection limit of 4.8615 n M.In addition,with the increasing of the addition concentration of vitamin B₂ in the Gd,N-CDs,the solution showed obvious changes from lilac to yellow.Based on this,the Gd,N-CDs can also be used as a colorimetric probe for the detection of vitamin B₂.The linear range of vitamin B₂ was 0.00～114.33μM with the detection limit of 18.84μM.The results of the Gd,N-CDs labeling recovery on actual tablets indicated that the prepared Gd,N-CDs can be used for the detection of vitamin B₂ in actual drugs without interference from foreign substances,which had certain significance for the detection of active ingredients in drugs and was expected to be used in the field of drug supervision.Chapter 4:The main research contents of this paper are summarized,and the possible future research directions of CDs are prospected.