基于金纳米簇探针的荧光猝灭检测铁离子

以D-色氨酸为保护剂和还原剂, 采用水热法快速制备了具有强荧光的金纳米簇(D-Trp@AuNCs); 以其作为荧光探针, 建立了基于荧光猝灭的选择性高灵敏检测Fe³⁺的传感方法. 利用透射电子显微镜(TEM)、 紫外-可见光谱(UV-Vis)和红外光谱(IR)等手段对制备的金纳米簇进行了表征, 并利用荧光光谱研究了D-Trp@AuNCs的荧光性能. 结果表明, D-Trp@AuNCs具有较好的生物相容性, 其最大激发波长为370 nm, 最大发射波长为460 nm; 向金纳米簇溶液中加入Fe³⁺后, D-Trp@AuNCs的荧光发生明显猝灭, 其猝灭程度与Fe³⁺的浓度在0.3~500.0 μmol/L范围内呈现良好的线性关系, 检出限为33.1 nmol/L(S/N=3). 将该荧光探针用于实际水样中Fe³⁺的检测, 回收率为86.6%~106.5%.     

用于汞离子检测和细胞成像的石墨相氮化碳量子点荧光探针

本文采用一步固相热解法，以尿素作为前体合成了石墨相氮化碳量子点(gCNQDs)．利用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和傅里叶变换红外光谱(FT-IR)等技术对g-CNQDs的粒径分布、元素组成、形貌结构和表面官能团进行表征．基于Hg²⁺淬灭g-CNQDs荧光的现象，构建可用于血样和尿样以及实际水样中Hg²⁺检测的荧光探针，在2.5～50.0μmol·L^-1范围内，Hg²⁺浓度与g-CNQDs相对荧光强度呈现良好的线性关系，检出限为1.5nmol·L^-1．在实际样品中检测Hg²⁺的加标回收率为97.17%～101.13%.g-CNQDs与Hg²⁺的相互作用机理主要为静态淬灭．该探针也被成功应用于肿瘤细胞成像．     

玉米苞衣热解法制备碳点及荧光猝灭法测定Hg2+

以农业废弃物玉米苞衣为碳源,采用一步热解法制备荧光碳点(CDs),利用透射电子显微镜、红外光谱、 X射线光电子能谱、紫外-可见光谱和荧光光谱等对CDs的结构和光学性能进行了表征。结果表明,制备得到的CDs呈球形,粒径约为5.5 nm,其表面富含羟基和羧基。CDs在紫外光照射下可以发出明亮的蓝色荧光。Hg²⁺对CDs溶液的荧光具有显著的猝灭作用,据此建立了检测Hg²⁺的新体系。在0～4.0μmol/L范围内,CDs溶液的荧光猝灭程度与Hg²⁺浓度呈良好的线性关系,检出限为0.011μmol/L。本方法适用于自来水和湖水水样中Hg²⁺的测定。     

三芳胺类荧光探针合成及对化妆品中Hg2+的检测

基于汞离子促进硫代缩醛脱保护作用,设计合成了一种三芳胺类荧光探针N-(1,1′-联苯-4-基)-N-(4-(双(乙基硫代)-甲基)苯基)-9,9-二甲基-9H-芴-2-胺(简称L),并采用核磁共振、红外光谱及高分辨质谱对其结构表征。荧光发射光谱表明,在乙腈(ACN)/4-羟乙基哌嗪乙磺酸(HEPES)(V∶V=9∶1,HEPES 10mmol·L^-1,pH=7.4)缓冲溶液中,探针可实现对Hg²⁺的“turn-off”检测,检测过程具有响应时间短、离子选择性好、抗共存金属离子干扰性强等优点。在0～20μmol·L^-1范围内,Hg²⁺浓度与荧光强度呈现良好线性关系,探针对Hg²⁺检测极限低至1.57×10^-8 mol·L^-1,可实现Hg²⁺的痕量检测。将探针L应用于化妆品中Hg²⁺检测,加标回收率96.3%～101.7%,相对标准偏差0.52%～2.76%,准确度较高,具有良好的应用前景。     

新型荧光探针罗丹明肉桂酰胺的合成及其用于荧光分光光度法测定汞

以罗丹明B和肉桂酸为主要反应物,制备了新型荧光探针罗丹明肉桂酰胺,并采用红外光谱、核磁和质谱对荧光探针的结构进行了表征。在含30%（φ）乙醇的pH 7.0 HEPES缓冲溶液中,荧光探针与Hg²⁺形成1比1的络合物,通过测定在发射波长584 nm处的荧光强度,与汞的浓度在1.0×10^-6mol·L^-1以内呈线性关系,方法的检出限（3s）为7.4×10^-9mol·L^-1。试验结果表明:该荧光探针对Hg²⁺具有很好的选择性,不受其他金属离子的干扰。     

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H2O2-丁基玫瑰红B-Fe2+体系的荧光猝灭法测定血清过氧化氢酶的活性

利用H₂O₂-Fe²⁺可以快速使丁基玫瑰红B(BRMB)发生荧光猝灭,而过氧化氢酶(CAT)对该猝灭有抑制效应,提出了基于H₂O₂-BRMB-Fe²⁺体系的荧光猝灭法测定血清CAT活性的方法。取血清样品10μL,加入1 mmol·L^-1 H₂O₂底液0.50 mL,于30℃恒温反应15 min,再依次加入0.02 mmol·L^-1 BRMB溶液0.70 mL、0.1 mol·L^-1冰乙酸-乙酸钠缓冲液(pH 4.2)1.00 mL和0.01 mol·L^-1 Fe²⁺溶液0.08 mL,于室温反应20 min后用水定容至10 mL,测定体系在590 nm发射波长处的荧光强度F;以煮死酶液为对照,按照同样的方法测定其在590 nm发射波长处的荧光强度F₀。结果表明：CAT活性在0.005...     

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。     

脱氧核糖核酸-银纳米簇荧光探针用于沙眼衣原体的定量检测

采用化学法合成脱氧核糖核酸-银纳米簇(DNA-AgNCs)荧光探针，并用于沙眼衣原体色氨酸合成酶β链基因(目标序列)的选择性荧光检测。在pH 6.6乙酸盐缓冲溶液中加入两条DNA探针和硝酸银，在还原剂硼氢化钠作用下合成了荧光强度大的DNA-AgNCs。在pH 5.5乙酸铵缓冲溶液中加入目标序列和DNA-AgNCs溶液，使混合溶液体积达到100μL,其中DNA-AgNCs的浓度达到1.5μmol·L^-1(以DNA浓度计),于15℃反应10 min,目标序列与其中一条DNA探针杂交，DNA-AgNCs结构被破坏，检测体系荧光猝灭。结果显示：DNA-AgNCs颗粒呈类球形，粒径约为2 nm,分散性良好且未发生团聚，荧光激发、发射波长分别在558,610 nm处。猝灭程度ΔF(目标序列添加后、前的检测体系荧光强度的差值)与目标序列浓度在0.23～1.10μmol·L^-1内呈线性关系，检出限(3s/k)为57 nmol·L^-1,测定值的相对标准偏差(n=11)为1.5%～4.9%。添加目标序列以及10倍目标序列浓度的同源序列、症状...     

检测汞离子的比色-荧光双通道探针的设计合成及应用

以7-羟基吩恶嗪酮(试卤灵)为荧光团、硫代甲酸苯酯为汞离子(Hg²⁺)识别基团,经一步简单有机合成反应,制备了比色-荧光双通道探针NMP。采用核磁共振氢谱(¹H NMR)、核磁共振碳谱(¹³C NMR)和高分辨率质谱(HRMS)表征了探针结构,利用吸收光谱和荧光发射光谱测试了探针对Hg²⁺的选择性和灵敏度。光谱测试结果表明,探针对Hg²⁺具有较好的选择性和检测灵敏度,检出限(3σ)为17 nmol/L。反应溶液由淡黄色变为紫红色,可对溶液中Hg²⁺进行比色检测,并可用于实际水样中Hg²⁺的检测。采用CCK-8法测试了探针的细胞毒性,结果表明,在探针浓度低于10μmol/L时,细胞存活率高于90%。共聚焦荧光显微成像结果表明,探针具有较好的细胞通透性,可对细胞内Hg²⁺进行荧光成像。     

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.     

A Smartphone-assisted Paper-based Analytical Device for Fluorescence Assay of Hg2+

Rapid, efficiency and portable detection systems in low-resource settings with limited laboratory equipment and technical expertise are urgently needed. Herein, an integrated platform composed of a paper-based analytical device and a smartphone detection system for Hg²⁺ onsite testing was developed. Nitrogen-doped carbon dots(N-CDs) were synthesized by a simple hydrothermal method using citric acid as the carbon source and ethanediamine as the nitrogen source, which gave out bright blue fluorescence under the excitation at 350 nm UV light and the absolute fluorescence quantum yield was 17.1%. The fluorescence of the prepared N-CDs can be effectively quenched by Hg²⁺. In addition, an external attachment of smartphone for illumination and external light interference was designed to trace the fluorescence signals, and a software application of Android system with simple operation program was developed to perform snapshot and image processing. The smartphone-assisted detection system was combined with the N-CDs decorated paper chip to achieve the sensitive detection of Hg²⁺ in water samples. This integrated method for reliable sensing of Hg²⁺ shows a good linear detection range of 10-800 μmol/L(R²=0.9595) with detection limit of 1.07×10^-8 mol/L.     

A new rhodamine-based fluorescent chemosensor for mercury in aqueous media

A new fluorescent ‘‘on–off' chemosensor for Hg2+initiated by a derivative of rhodamine B was designed and synthesized. Compound 1 exhibited high sensitivity and selectivity for Hg2+over other commonly coexistent metal ions in aqueous media. Upon the addition of Hg2+, the spirocyclic ring of probe is opened and a significant enhancement of visible color and fluorescence in the range of 500–600 nm is observed. The colorimetric and fluorescent response to Hg2+can be conveniently detected by the naked eye, which provides a facile method for visual detection of Hg2+. From the molecular structure and spectral results of 1, an irreversible, hydrolysis, desulfurization reaction mechanism is proposed.     

Ag+存在下催化还原铬黑T及应用于Ag+检测

以铬黑T(EBT)为探针,在有Ag⁺存在的最优条件下,EBT被NaBH 4催化还原,体系在445 nm发射波长处荧光强度明显增强,基于此构建一种光学测定溶液中微量Ag⁺的方法。在最优条件下,Ag⁺浓度在(7.5×10-9~1.0×10^-6 mol·L^-1)范围内呈良好的线性关系,线性回归方程为ΔI F=5.59×10⁸ c-31(c,mol·L^-1,r=0.9966),Ag⁺的最低有效检测浓度为6.0×10^-8 mol·L^-1。在最优条件下,运用该方法对样品中Ag⁺浓度进行检测,样品中Ag⁺浓度的检测回收率在98.8%~102.4%之间,RSD=2.1%。该检测方法能够对水溶液中微量的Ag⁺进行有效定量检测,且操作简单、检测限低、灵敏度高。     

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.     

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。     

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⁺.     

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.