Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,an...Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,and precursor,respectively.Several technologies were employed to investigate the structures and optical properties of FA@Ag NCs,including transmission electron microscopy(TEM),X-ray photoelectron spectrometer(XPS),Fourier transform infrared spectrometer(FTIR),X-ray diffractometer(XRD),fluorescence spectrometer,and ultraviolet visible absorption spectrometer.FA@Ag NCs were suggested to be highly dispersed and spherical with a size of around 2.8 nm.Moreover,the maximum excitation and emission wavelengths of FA@Ag NCs were 370 and 447 nm,respectively.Under the optimal detection conditions,FA@Ag NCs could be used to effectively detect malachite green with the linear detection range of 0.5-200μmol·L^(-1).The detection limit was 0.084μmol·L^(-1).The fluorescence-quenching mechanism was ascribed to the static quenching.The detection system based on FA@AgNCs was successfully used for the detection of malachite green in actual samples with good accuracy and reproducibility.展开更多
Chromium is a harmful contaminant showing mutagenicity and carcinogenicity.Therefore,detection of chromium requires the development of low-cost and high-sensitivity sensors.Herein,blue-fluorescent carbon quantum dots ...Chromium is a harmful contaminant showing mutagenicity and carcinogenicity.Therefore,detection of chromium requires the development of low-cost and high-sensitivity sensors.Herein,blue-fluorescent carbon quantum dots were synthesized by one-step hydrothermal method from alkali-soluble Poria cocos polysaccharide,which is green source,cheap and easy to obtain,and has no pharmacological activity due to low water solubility.These carbon quantum dots exhibit good fluorescence stability,water solubility,anti-interference and low cytotoxicity,and can be specifically combined with the detection of Cr(Ⅵ)to form a non-fluorescent complex that causes fluorescence quenching,so they can be used as a label-free nanosensor.High-sensitivity detection of Cr(Ⅵ)was achieved through internal filtering and static quenching effects.The fluorescence quenching degree of carbon dots fluorescent probe showed a good linear relationship with Cr(Ⅵ)concentration in the range of 1-100μM.The linear equation was F;/F=0.9942+0.01472[Cr(Ⅵ)](R;=0.9922),and the detection limit can be as low as 0.25μM(S/N=3),which has been successfully applied to Cr(Ⅵ)detection in actual water samples herein.展开更多
Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen...Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen-doped carbon dots（B,N-carbon dots）.The B,N-carbon dots emitted green fluorescence and displayed high resistance to both photo bleaching and ionic strength.A facile fluorescence sensing approach for Cu^2＋ was fabricated via static fluorescence quenching.Under optimal conditions,a rapid detection of Cu^2＋ could be completed in 2 min with a linearity ranging from 1 μmol/L to 25 μmol/L and a detection limit of 0.3 μmol/L Furthermore,the proposed method showed potential applications for the detection of Cu^2＋ in natural water samples.展开更多
Modulating photoluminescent(PL)materials is crucial for applications such as super-resolution microscopy.The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photosw...Modulating photoluminescent(PL)materials is crucial for applications such as super-resolution microscopy.The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photoswitches.Here we report an optically PL switchable system by mixing carbon quantum dots(CQDs)and diarylethene(DAE)molecular photoswitches.The PL on/off states of CQDs,switched with alternating visible and UV light,achieve a PL on/off ratio of500 and stable reversibility over 20 cycles.The mechanism of our design is revealed by PL lifetime measurements,temperature-dependent PL spectroscopy,and density functional theory(DFT)calculations,confirming that efficient static quenching and the inner filter effect between CQDs and closed DAEs are the keys to achieving such outstanding performance.展开更多
It is particularly important to monitor Cr(Ⅵ)for its high toxicity.In this paper,a novel,simple,low-cost and"on-off-on"fluorescence sensor of carbon dots doped with nitrogen and phosphorus(N,P-CDs)was devel...It is particularly important to monitor Cr(Ⅵ)for its high toxicity.In this paper,a novel,simple,low-cost and"on-off-on"fluorescence sensor of carbon dots doped with nitrogen and phosphorus(N,P-CDs)was developed via one-step hydrothermal method for highly sensitive and good selective detection of Cr(Ⅵ)and ascorbic acid(AA).The prepared N,P-CDs exhibited the ability for detection of Cr(Ⅵ)based on the inner filter effect(IFE)and static quenching.Under optimized conditions,the fluorescence quenching efficiency of N,P-CDs showed a good linear correlation with Cr(Ⅵ)concentration ranged from0.68 to 87.38μmol/L(R^(2)=0.9946).The limit of detection(LOD)was 0.18μmol/L,which was acceptable compared with the maximum Cr(Ⅵ)concentration of 0.96μmol/L in drinking water prescribed by WHO.In addition,the N,P-CDs/Cr(Ⅵ)hybrid were also used as"turn-on"fluorescent transducers for detecting AA with a wide linear region ranged from 0.02 to933.33μmol/L(R^(2)=0.9972).Furthermore,the N,P-CDs fluorescence sensor had admissible applicability for Cr(Ⅵ)and AA detection in actual water samples with acceptable recovery rate,indicating that the fluorescence sensor had great application potential in environmental monitoring and food field.展开更多
文摘Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,and precursor,respectively.Several technologies were employed to investigate the structures and optical properties of FA@Ag NCs,including transmission electron microscopy(TEM),X-ray photoelectron spectrometer(XPS),Fourier transform infrared spectrometer(FTIR),X-ray diffractometer(XRD),fluorescence spectrometer,and ultraviolet visible absorption spectrometer.FA@Ag NCs were suggested to be highly dispersed and spherical with a size of around 2.8 nm.Moreover,the maximum excitation and emission wavelengths of FA@Ag NCs were 370 and 447 nm,respectively.Under the optimal detection conditions,FA@Ag NCs could be used to effectively detect malachite green with the linear detection range of 0.5-200μmol·L^(-1).The detection limit was 0.084μmol·L^(-1).The fluorescence-quenching mechanism was ascribed to the static quenching.The detection system based on FA@AgNCs was successfully used for the detection of malachite green in actual samples with good accuracy and reproducibility.
基金financially supported by the Natural Science Foundation of Anhui University of Chinese Medicine (Grant No.: 2018zrzd04)Anhui Provincial Natural Science Foundation (Grant No.: 1908085QH351)+2 种基金Major Science and Technology Projects of Anhui Province (Grant No.: 18030801131)National Key Research and Development Project (Grant No.: 2017YFC1701600)Anhui Province’s Central Special Fund for Local Science and Technology Development (Grant No.: 201907d07050002)
文摘Chromium is a harmful contaminant showing mutagenicity and carcinogenicity.Therefore,detection of chromium requires the development of low-cost and high-sensitivity sensors.Herein,blue-fluorescent carbon quantum dots were synthesized by one-step hydrothermal method from alkali-soluble Poria cocos polysaccharide,which is green source,cheap and easy to obtain,and has no pharmacological activity due to low water solubility.These carbon quantum dots exhibit good fluorescence stability,water solubility,anti-interference and low cytotoxicity,and can be specifically combined with the detection of Cr(Ⅵ)to form a non-fluorescent complex that causes fluorescence quenching,so they can be used as a label-free nanosensor.High-sensitivity detection of Cr(Ⅵ)was achieved through internal filtering and static quenching effects.The fluorescence quenching degree of carbon dots fluorescent probe showed a good linear relationship with Cr(Ⅵ)concentration in the range of 1-100μM.The linear equation was F;/F=0.9942+0.01472[Cr(Ⅵ)](R;=0.9922),and the detection limit can be as low as 0.25μM(S/N=3),which has been successfully applied to Cr(Ⅵ)detection in actual water samples herein.
基金financially supported by the National Natural Science Foundation of China(No.21375112)the Marine hightech industry development projects of Fujian Province(No.2015-19)
文摘Heteroatom doping is an efficient approach to regulate the fluorescence properties of carbon dots.Using aminophenylboronic acid as the raw material,a combustion method was developed for the synthesis of boron,nitrogen-doped carbon dots（B,N-carbon dots）.The B,N-carbon dots emitted green fluorescence and displayed high resistance to both photo bleaching and ionic strength.A facile fluorescence sensing approach for Cu^2＋ was fabricated via static fluorescence quenching.Under optimal conditions,a rapid detection of Cu^2＋ could be completed in 2 min with a linearity ranging from 1 μmol/L to 25 μmol/L and a detection limit of 0.3 μmol/L Furthermore,the proposed method showed potential applications for the detection of Cu^2＋ in natural water samples.
基金support from the National Key Research and Development Program of China(No.2023YFB3609300)the National Natural Science Foundation of China(Nos.62205240 and 12274320)support from the Swedish Foundation for International Cooperation in Research and Higher Education(STINT IB2023-9189)。
文摘Modulating photoluminescent(PL)materials is crucial for applications such as super-resolution microscopy.The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photoswitches.Here we report an optically PL switchable system by mixing carbon quantum dots(CQDs)and diarylethene(DAE)molecular photoswitches.The PL on/off states of CQDs,switched with alternating visible and UV light,achieve a PL on/off ratio of500 and stable reversibility over 20 cycles.The mechanism of our design is revealed by PL lifetime measurements,temperature-dependent PL spectroscopy,and density functional theory(DFT)calculations,confirming that efficient static quenching and the inner filter effect between CQDs and closed DAEs are the keys to achieving such outstanding performance.
基金financially sponsored by the National Natural Science Foundation of China(21777131,22176154)Science and Technology Department Foundation of Sichuan Province(22ZDYF1945)
文摘It is particularly important to monitor Cr(Ⅵ)for its high toxicity.In this paper,a novel,simple,low-cost and"on-off-on"fluorescence sensor of carbon dots doped with nitrogen and phosphorus(N,P-CDs)was developed via one-step hydrothermal method for highly sensitive and good selective detection of Cr(Ⅵ)and ascorbic acid(AA).The prepared N,P-CDs exhibited the ability for detection of Cr(Ⅵ)based on the inner filter effect(IFE)and static quenching.Under optimized conditions,the fluorescence quenching efficiency of N,P-CDs showed a good linear correlation with Cr(Ⅵ)concentration ranged from0.68 to 87.38μmol/L(R^(2)=0.9946).The limit of detection(LOD)was 0.18μmol/L,which was acceptable compared with the maximum Cr(Ⅵ)concentration of 0.96μmol/L in drinking water prescribed by WHO.In addition,the N,P-CDs/Cr(Ⅵ)hybrid were also used as"turn-on"fluorescent transducers for detecting AA with a wide linear region ranged from 0.02 to933.33μmol/L(R^(2)=0.9972).Furthermore,the N,P-CDs fluorescence sensor had admissible applicability for Cr(Ⅵ)and AA detection in actual water samples with acceptable recovery rate,indicating that the fluorescence sensor had great application potential in environmental monitoring and food field.
