基于氮掺杂碳点的荧光增强简便、快速而准确地检测环丙沙星

以苹果酸为碳源,磷酸铵提供氮源,采用固态热解法一步合成一种水溶性的、氮掺杂的蓝色荧光碳点(N-CDs)。 所得到的碳点荧光量子产率高达20.7%,形貌近似球形,平均粒径约为3.3 nm。 基于环丙沙星(CIP)对碳点的荧光增强作用,建立了一种CIP的定量检测方法。 最佳实验参数为:碳点浓度为7.5 μg/mL,pH值为5.9,孵化时间为5 min。 在此实验条件下,碳点的荧光强度增加值(ΔF)和CIP的浓度在0.39~40.00 μmol/L范围内呈良好的线性关系,方法的检出限为0.12 μmol/L,相对标准偏差(n=5)为4.2%。 干扰实验结果指出,除了铜离子具有明显的影响外,其它共存物质的干扰可以忽略不计,而铜离子的干扰可通过加入草酸铵来掩蔽。 最后利用所构建的荧光传感器对实际样品中CIP进行检测,回收率在93%~107%之间。 本研究为CIP定量分析提供了一种简单、快速、灵敏度高、选择性好而有效的测定方法。     

新型荧光碳点的制备及其在Hg2+检测中的应用

以中药材川佛手为碳源,通过高温热解产生的烟制备了平均粒径为6 nm的新型荧光碳点,其最大激发波长285 nm,最大荧光发射波长340 nm。 基于碳点良好的荧光性能及Hg²⁺对碳点荧光的猝灭作用,建立了检测Hg²⁺的新方法。 结果表明,在0.2 mol/L磷酸盐缓冲溶液(pH=7.0)中,响应时间为2 min时,该方法具有良好的选择性和抗干扰能力,检测Hg²⁺浓度的线性范围为0.2~40 μmol/L,相关系数为r=0.9996,检出限为0.052 μmol/L。 当加入2.0和40.0 μmol/L Hg²⁺到实际水样后,相对标准偏差(RSD)和加标回收率分别为0.3%~2.4%和99.5%~101.1%,可用于实际水样中Hg²⁺的分析检测。     

喹啉酮-香豆素类Hg2+比色荧光探针的合成及应用

设计合成了新型喹啉酮-香豆素类比色荧光探针7-二乙氨基-3-[3-(7-二乙氨基)香豆素基-3-氧代丙烯基]喹啉-2-酮(QCO), 用于检测水溶液中的Hg²⁺. 探针QCO对Hg²⁺表现出高选择性和强抗干扰性. 此外, Hg²⁺引起探针QCO溶液的颜色变化明显, 可裸眼识别. 比色法中, 吸收值比(A₅₀₀/A₃₈₀)与Hg²⁺浓度呈良好的线性关系, 其检出限为2.62×10^-8 mol/L. 荧光法中, 探针QCO对Hg²⁺的检出限为5.42×10^-8 mol/L. 经等摩尔变化( Job’s Plot)法、 质谱及红外光谱验证, 探针QCO与Hg²⁺形成络合比为1∶1(摩尔比)的络合物. 硅胶板实验和加标回收率实验结果表明, 探针QCO可用于检测实际水样中的Hg²⁺.     

Organic-inorganic hybrid fluorescent sensor thin films of rhodamine B embedded Ag-SBA 15 for selective recognition of Hg (Ⅱ) ions in water

Nowadays, the rapid and effective detection of low doses of heavy metal pollutants in contaminated water is a timely challenge in environmental pollution research. In this study, a rapid and highly sensitive assay for the detection of Hg~(2+)based on quenching of metal-enhanced fluorescence of rhodamine B(RB)has been fabricated. RB and silver nanoparticle were incorporated into the mesoporous siliceous framework spin cast on a quartz glass through post-synthetic incorporation method. The morphology and crystallinity of mesoporous structure and Ag nanoparticle were characterized by transmission electron microscopy and X-ray diffraction analyses. Photoluminescence assays on the hybrid thin film of RB-Ag-SBA15 showed a high enhancement when compared to the intensity of silver free SBA15-RB in the wavelength of 575 nm. The fluorescence of RB-Ag-SBA15 thin film decreased gradually with the increase in the concentration of Hg~(2+)and the detection limits were 10.54 nmol/L. Furthermore, the fluorescence intensity increased linearly with the concentration of Hg~(2+)in the range from 1.0 ? 10à8mol/L to10 ? 10à8mol/L, with a response time of a few seconds. In addition, this system offers a high selectivity over interfering cations such as Cd~(2+) and Pb~(2+). Overall, we have developed an optical assay having a wellordered mesoporous SBA15 containing Ag-RBfor selective detection of Hg~(2+)in aqueous solution. The scheme combines the advantages of specific binding interactions between Hg~(2+)and RB molecule and optical emission properties of RB. The method is suitable for a single-shot and irreversible analytical assay in a quartz glass/microtiter plate.     

高选择性检测Hg2+的喹啉酮衍生物荧光探针的合成及应用

设计合成了一种以喹啉酮为荧光团,具有新型结构的荧光探针（E）-N-（4-甲基-2-氧代-1,2-二氢喹啉-7-基）-3-（3-苯基-[1,2,4]三唑[3,4-b][1,3,4]噻二唑-6-基）丙烯酰胺（MNT）.研究结果表明,MNT可通过不饱和酰胺键异构化后与Hg²⁺配位,从而产生显著的荧光猝灭.1,2,4-三唑[3,4-b]-1,3,4-噻二唑缺电子的特征有助于提高猝灭效果的同时,能提供与Hg²⁺配位的杂原子.MNT探针对Hg²⁺具有高选择性、较高的量子产率和较强的抗干扰性,检测限为6.35×10^-8 mol/L,响应时间25 s.进一步研究发现,MNT在pH=4~13范围内均能特异性检测Hg²⁺.基于核磁滴定实验结果推测了该探针荧光检测Hg²⁺的机理,并由Job’s曲线确定了MNT与Hg²⁺之间的配位比为2：1.MNT在实际水样中的应用结果表明其可作为检测Hg²⁺的荧光探针.     

基于牛血清白蛋白功能化金纳米棒的荧光探针测定Hg2+

建立了一种以牛血清白蛋白功能化的金纳米棒(BSA-Cys-GNRs)为荧光探针检测Hg²⁺的新方法。以半胱氨酸作为连接臂成功将牛血清白蛋白修饰在金纳米棒表面,通过紫外可见吸收光谱、荧光光谱、红外光谱和荧光倒置显微镜等多种分析方法对材料进行表征。研究发现,在295nm波长光激发下,BSA-Cys-GNRs探针在338nm显示强荧光,而Hg²⁺能够有效地猝灭BSA-Cys-GNRs的荧光。对一系列影响猝灭效果的因素进行考察,得出pH 4.0、孵育时间5.0min为最佳检测条件。Mn²⁺、K⁺、Ni²⁺、Na⁺、Cr³⁺、Cd²⁺、Mg²⁺、Cu²⁺、Ca²⁺、Al³⁺和Zn²⁺对BSA-Cys-GNRs的荧光信号没有明显的影响。当Hg²⁺的浓度为0.04444~8.888μmol·L^-1时,荧光猝灭效率与Hg²⁺的浓度之间存在良好的线性关系,检测限为8.08nmol·L^-1。将该方法用于环境水样中Hg²⁺的检测,回收率为98.9%~105.0%。     

氮掺杂鸡毛碳点荧光关开探针用于测定百草枯

以鸡毛和乙二胺为碳源和氮源,通过一步水热法合成强荧光性能的氮掺杂碳量子点(N-CQDs),并优化其制备和掺杂条件。该碳量子点具有良好的光学、结构性质和稳定性,平均粒径7.89 nm,荧光量子产率为14%。最大激发波长为320 nm,最大发射波长为386 nm。Hg²⁺存在条件下N-CQDs溶液的荧光被猝灭(关),添加百草枯后猝灭的荧光被恢复(开)。通过N-CQDs/Hg²⁺体系设计了荧光"关-开"方法,在最佳条件下,百草枯在0.05~1.0μg/mL范围内具有良好的线性,线性方程为ΔF=92.41X+123.31(R²=0.9989),检出限为16μg/L,加标回收率为95.3%~104.4%,RSD<3.8%。以鸡毛为原料制备的高选择性和灵敏性的荧光"关-开"探针方法可有效检测实际样品中的百草枯。     

冠醚功能化的栅控石墨烯场效应晶体管的制备及对汞离子的检测

Hg²⁺是一种具有生物蓄积性和毒性的重金属, 对环境和人类健康均可造成严重损害. 因此, 开发便捷的Hg²⁺传感器非常必要. 本文基于溶液栅控石墨烯场效应晶体管的优异性能, 通过氮硫杂冠醚的尺寸效应以及冠醚与Hg²⁺的螯合作用来特异性识别Hg²⁺, 制备了一种冠醚功能化栅极的溶液栅控石墨烯场效应晶体管(SGGT)传感器. 该SGGT传感器因其固有的信号放大功能而比传统电化学检测Hg²⁺更灵敏, 其检出限为1×10^-12 mol/L, 比传统电化学传感器降低了2~3个数量级, 在1×10^-12~1×10^-7 mol/L检测范围内, 狄拉克点的变化值与目标物浓度的对数值之间存在良好的线性关系, 同时具有极高的选择性. 对实际湖水样品的检测效果良好, 对Hg²⁺的检测标准偏差为1.10%~3.77%. 本文结果表明, 该晶体管传感器可以对Hg²⁺进行高选择和高灵敏检测.     

具有荧光增强性能的罗丹明B衍生物的合成及其对汞离子的检测

利用汞离子可以诱导罗丹明B衍生物的螺环结构发生开环反应并产生荧光增强效果这一特性,设计并合成了两种新型的荧光化学传感器2-噻吩甲醛罗丹明B酰肼(RhBTh)和苯甲醛罗丹明B酰肼(RhBAr),并研究了二者在汞离子检测中的应用.研究结果表明,RhBTh与RhBAr对汞离子均表现出非常好的荧光增强效果,检测过程中其它金属离子不会对检测结果产生明显的干扰.二者对汞离子的检测限分别为7.8 nmol/L和12.5 nmol/L.实验表明RhBTh和RhBAr对汞离子均具有良好的灵敏度和选择性.     

A squaraine based fluorescent probe for mercury ion via coordination induced deaggregation signaling

Due to the high affinity between dithiocarbamate(DTC) and Hg2+,a fluorescent probe based on squaraine chromophore with DTC side arm for Hg2+via coordination induced deaggregation signaling has been designed and synthesized.Squaraine has a high tendency to aggregate in aqueous solution,and such self-aggregation usually results in a dramatic absorption spectral broadening with fluorescence emission quenching.The combination of the DTC side arm of the probe with Hg2+induces steric hindrance,leading to the deaggregation of the dye complex,companying with a fluorescence emission restoration.In EtOH–H2O(20:80,v/v) solution,this ‘‘turn on' fluorescent probe has high selectivity and sensitivity toward Hg2+over other metal ions,and the limit of detection for Hg2+was estimated as2.19 ? 10à8mol/L by 3s/k.     

A Fluorescent and Colorimetric Probe Based on Isatin-appended Rhodamine for the Detection of Hg2+

A new fluorescent probe for the detection of Hg²⁺ was designed and synthesized via attaching N-methylisatin to rhodamine B hydrazide through an imine linkage. In an ethanol-Tris buffer medium, the addition of Hg²⁺ caused a strong orange fluorescence and a visual color change from colorless to pink. Other coexisting metal ions did not interfere with the detection of Hg²⁺. The research on the detection of Hg²⁺ in natural water suggested the possibility of practical applications in environment monitoring. Based on ESI-MS analysis, the Hg²⁺-sensing mechanism was proposed.     

A Highly Selective Fluorescent Chemosensor for Cu2+

A new Zn²⁺ probe L2-Zn(L2=naphthofuran carbonylhydrazone derivant) was synthesized as a fluorescence chemosensor for Cu²⁺, by which Cu²⁺ ion could be detected with high selectivity and sensitivity in a wide pH range via a displacement “turn-off” signaling strategy. Whereas the coordination between Zn²⁺ and L2 resulted in a considerable enhancement of typical luminescence of a naphthalofuran group in complex L2-Zn, the addition of Cu²⁺ ion led to a dramatic decrease in the emission intensity of probe L2-Zn at about 503 nm(excitation at 423 nm). The competitive fluorescent experiments showed that other metal ions, such as Hg²⁺, Fe³⁺, Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺ and Mg²⁺ could not impact the detection of Cu²⁺. The detection limit of the novel probe L2-Zn for Cu²⁺ ion was as low as 2.3×10^-7 mol/L, which is far lower than the guideline value of 1.6×10^-5 mol/L of the United States Environmental Protection Agency.     

Rhodamine 6G-based Chemosensor for the Visual Detection of Cu2＋ and Fluorescent Detection of Hg2＋ in Water

A novel water soluble chemosensor 1 based on rhodamine 6G spirolactam scaffold has been synthesized and characterized.Upon addition of a wide range of the environmentally and biologically relevant metal ions,chemosensor 1 shows a colorimetric selective Cu2＋ recognition from colorless to pink confirmed by UV-Vis absorption spectral changes,while it also exhibits a fluorometric selective Hg2＋ recognition by fluorescence spectrometry.An absorption enhancement factor over 17-fold with 1-Cu2＋ complex and a fluorescent enhancement factor over 45-fold with 1-Hg2＋ complex were observed.Their recognition mechanisms were assumed to be a 1：1 stoichiometry for 1-Cu2＋ complex and a 1：2 stoichiometry for 1-Hg2＋ complex,respectively,which were proposed to be different ligation leading to the ring-opening of rhodarnine 6G spirolactam.Furthermore,the detection limits for CU2＋ or Hg2＋ were 3.3 × 10-8 or 1.7x 10-7 mol/L,respectively.     

荧光素-层状双金属氢氧化物复合体的发光性能及对Fe3+的荧光识别

采用离子交换法合成了FLN/OS-LDH复合体(FLN: 荧光素, OS: 1-辛烷磺酸钠, LDH: 镁铝型层状双金属氢氧化物), 并研究了其光致发光和对Fe³⁺的识别性能. 固态时, FLN不发光, 而FLN/OS-LDH复合体呈黄绿色荧光(发射波长为565 nm), 是荧光素(FLN)的特征发射光. 在甲酰胺(FM)中可将该复合体方便剥离为胶状悬浮液, 其发射波长发生蓝移, 为绿光发射(531 nm). 研究了复合体剥离液对金属离子的荧光识别特性, 发现其对Fe³⁺的选择性识别能力很强, 远优于其它离子(Mg²⁺, Ni²⁺, Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺, Cd²⁺和Hg²⁺). 该复合体与Fe³⁺结合发生荧光猝灭现象, 可将其用作检测Fe³⁺的荧光传感器. Fe³⁺检测限为1.27×10^-7 mol/L, 猝灭常数(K_sv)为3.44×10² L/mol.     

高选择性快速识别汞（Ⅱ）离子的磺酰腙型探针的合成及在吸附中的应用

以苯磺酰肼和1-芘甲醛为原料,设计合成了一种结构简单的可快速识别汞（Ⅱ）离子（Hg²⁺）的磺酰腙型荧光探针（Z）-N'-（芘-1-基亚甲基）苯磺酰腙（BSB）,并通过氢核磁共振波谱仪（¹H NMR）对其结构进行了表征。BSB对Hg²⁺展示出高选择性、专一性和快速响应性,检测限为2.07×10^-7 mol/L,响应时间仅需15 s。通过job's曲线,¹H NMR滴定实验和高分辨率质谱（HRMS）对响应机理进行了探究,并且BSB可以检测不同水样中的Hg²⁺。有趣的是,将BSB和聚丙烯酰胺（PAM）相掺杂制备出了对Hg²⁺具有高去除性能的新型高分子材料（PAM?BSB）,去除率达到99.63%,并通过扫描电子显微镜（SEM）对PAM?BSB吸附前后的微观形貌进行了观察。     

Field-portable ratiometric fluorescence imaging of dual-color label-free carbon dots for uranyl ions detection with cellphone-based optical platform

Under the public spotlight, uranyl (UO₂²⁺) ions has attracted considerable attention for the extreme radioactive and chemical toxicity to ourselves and our environment. Herein, we present a simple and effective ratiometric fluorescence imaging method for the visualizing and quantitative detection UO₂²⁺ ions by cellphone-based optical platform. The sensing solution was prepared by mixing label-free red carbon dots (r-CDs) and blue carbon dots (b-CDs) together with a fixed photoluminescence intensity ratio of 4:1. When UO₂²⁺ ions were added, the fluorescence of r-CDs can be selectively quenched, while the fluorescence of b-CDs remains stable without spectral changes. With the gradually increase the amounts of UO₂²⁺ ions, the different response of dual-color CDs resulted in a signification color evolution from deep red to dark purple under the ultraviolet (UV) light illumination. Then, a cellphone-based optical platform was constructed for directly imaging the color change of the samples, and the built-in Colorpicker APP quickly output the red, green and blue (RGB) channel values of these images within one second. Interesting, there was a linear relationship between the ratio of red and blue (R/B) channel values and UO₂²⁺ ions concentration from 0 μmol/L to 30.0 μmol/L (R² = 0.92804) with the detection limit of ~8.15 μmol/L (signal-to-noise ratio of 3). In addition, the optical platform has also been applied to the quantification of UO₂²⁺ ions in tap water and river water sample. With the advantage of low-cost, portable, easy to operation, we anticipate that this method would greatly improve the accessibility of UO₂²⁺ ions detection even in resource-limited areas.     

A rhodamine derivative for Hg2+-selective colorimetric and fluorescent sensing and its application to in vivo imaging

A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg~(2+)-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg~(2+)generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg~(2+)in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg~(2+)in environmental, tobacco and biological applications.     

Synthesis and properties of three novel rhodamine-based fluorescent sensors for Hg2+

Three novel rhodamine-based Hg~(2+) fluorescent sensors were designed and synthesized. The sensors could work in semi-aqueous solutions with nearly neutral p H and showed high selectivity and sensitivity to Hg~(2+) with remarkable fluorescence enhancement. For these three sensors, the linear working range broadened(0–80, 0–100 and 0–140 μmol/L, respectively) and the sensitivity increased(7.7, 15.5 and 17.6 folds of the fluorescence enhancement and 512, 66.2 and 37.6 ppb of the detection limit) with the rising of the thiourea-unit numbers. Furthermore the sensors exhibited excellent interference immunity to multiple environmentally and biologically relevant metal ions. Pond and tap water assay showed good practicability of the sensors. The number of the bound Hg~(2+) equaling to that of the thiourea units and the irreversible recognition process implied a new interaction way between Hg~(2+) and the sensor.     

氮硫掺杂碳点的制备及检测铜离子

以柠檬酸为碳源,通过水热合成制备N、S掺杂的蓝色荧光碳点（NS-CDs）,用于实际样品中铜离子检测。采用高分辨率透射电子显微镜、X射线衍射光谱、红外吸收光谱、X射线光电子能谱、荧光光谱对其结构、组成和光学性质进行表征。结果表明,NS-CDs分散性好,尺寸分布在0.6~2.2 nm之间,具有无定形碳的结构;碳点表面含有羟基、羧基、酰胺等官能团,C、N、O和S元素质量分数别为54.01%、24.49%、19.39%及2.11%;该碳点具有良好的耐盐性、pH稳定性、光稳定性,其荧光量子产率为25%。基于Cu²⁺离子与碳点表面多个官能团发生相互作用形成聚集的网络结构,导致荧光猝灭的现象,建立了检测Cu²⁺的荧光分析新方法,本方法对Cu²⁺离子具有良好的选择性和较高的灵敏度,在0.2~10、10~50和50~100 μmol/L范围均有良好的线性响应,检出限为41 nmol/L（S/N=3）满足《土壤环境质量标准》对土壤中Cu²⁺检测国家标准的要求（6.25 mmol/L）。测定了实际土壤中Cu²⁺的含量,检测结果为2.55 μmol/L,加标回收率在104.9%～105.6%之间,实现了Cu²⁺的快速、灵敏、高选择性检测。     

Thiourea functionalized CdSe/CdS quantum dots as a fluorescent sensor for mercury ion detection

CdSe/CdS quantum dots(QDs) functionalized by thiourea(TU) were synthesized and used as a fluorescent sensor for mercury ion detection.The TU-functionalized QDs were prepared by bonding TU via electrostatic interaction to the core/shell CdSe/CdS QDs after capping with thioglycolic acid(TGA).It was observed that the fluorescence of the functionalized QDs was quenched upon the addition of Hg~(2+).The quantitative detection of Hg~(2+) with this fluorescent sensor could be conducted based on the linear relationship between the extent of quenching and the concentration of Hg~(2+) added in the range of1-300 μg L~(-1).A detection limit of 0.56 μg L~(-1) was achieved.The sensor showed superior selectivity for Hg~(2+) and was successfully applied to the determination of mercury in environmental samples with satisfactory results.