含苯并噻唑基香豆素类铜离子探针的合成及其性能

以香豆素为母体设计合成了一个新型荧光淬灭香豆素类衍生物探针,并研究了其识别能力和结合方式等。研究发现,该探针对Cu2+具有很高选择性、灵敏性,以及较高的荧光淬灭率(达95.2%)。并且当Cu2+浓度在3×10-6~1.5×10-5mol/L范围内,该探针的荧光强度和离子浓度具有较好的线性关系。     

基于香豆素衍生物的反应型硫化氢荧光探针的合成与应用

该文基于光诱导电子转移(PET)机制,利用H_2S诱导探针分子结构中的2,4-二硝基苯醚水解,抑制PET过程,合成一种反应型H_2S荧光探针。利用NMR和MS对探针1的结构进行表征。通过光谱学测试和生物学细胞实验证实,相对于其他测试物质(阴、阳离子及生物分子),它对H_2S具有良好的选择性和灵敏度,可以在生理条件下检测H_2S。当H_2S加入到探针溶液后,溶液呈现出绿色荧光,在490 nm荧光强度恢复75倍,当探针的浓度为10.0μmol/L时,其对H_2S的检测限为3.0×10~(-8) mol/L;同时,探针成功实现细胞内H_2S的荧光成像,为其在生物学及医学中的实际应用奠定实验基础。     

N掺杂石墨烯量子点的制备及在Fe~(3+)检测中的应用研究

研究了用热解柠檬酸制备发蓝光的石墨烯量子点(GQDs),并在此基础上,用(NH4)2CO3作N源,在水热条件下制备N掺杂石墨烯量子点(N-GQDs)。通过透射电子显微镜(TEM)、X射线光电子能谱仪(XPS)、傅里叶红外光谱仪(FT-IR)、紫外-可见吸收光谱仪(UV-Vis)、荧光光谱仪等对样品的结构和光学性能进行表征。此外,基于荧光淬灭原理,利用N-GQDs构建了一种检测Fe3+的荧光探针。研究表明,N-GQDs的荧光强度随Fe3+浓度的增大而降低,在0~60μmol/L范围内,N-GQDs荧光强度与Fe3+浓度有较好的线性关系,且该探针的检测限低达0.925μmol/L。     

微波绿色合成N,S共掺杂碳点及其在Fe3+检测和温度传感方面的应用

以韭菜为前驱体,采用微波法一步绿色合成N,S共掺杂的粒径均匀、分散性好的碳点。所合成的碳点近似球状,粒径2.0-5.0 nm。在365 nm的紫外灯照射下发明亮的蓝色荧光,发射峰具有激发波长依赖性。Fe³⁺对所制备的碳点有明显选择性荧光猝灭现象。在5-300μmol/L的范围内,荧光猝灭程度(F/F₀)与Fe³⁺浓度呈现良好的线性关系(R=0.9930),检测限为4.0μmol/L。同时探测温度对制备碳点的影响,在20-55℃范围内,碳点荧光强度与温度具有较好的线性响应。由于生理温度范围在此温度范围内,所制备的碳点可用于细胞温度传感。     

四氧化三钴的制备及在过氧化氢电化学传感器中的应用

以六水氯化钴、聚乙烯亚胺和辛胺为主要原料,通过水热法得到片状氢氧化钴（Co(OH)2）前驱体,并进一步煅烧得到片状Co3O4电催化活性材料。采用滴涂法制备Co3O4/GCE修饰电极,通过循环伏安法和计时安培法对过氧化氢（H2O2）进行电化学检测分析,研究煅烧温度对所得到的Co3O4形貌以及H2O2检测性能的影响。结果表明：经200 ℃煅烧得到的Co3O4晶体为稳定的六方形片状结构,修饰电极200-Co3O4/GCE对H2O2检测表现出最高的响应电流值,该电极电流响应值与H2O2浓度在0.01~0.20 mmol/L范围内具有良好线性关系,检测限为6.53 μmol/L(S/N=3),灵敏度为875.66 μA/(mmol·L-1·cm2);同时修饰电极Co3O4/GCE在对H2O2检测中表现出较好抗干扰能力。     

氨基功能化荧光碳量子点的制备及对铜离子的检测

以柠檬酸作为碳源,聚乙烯亚胺(BPEI)作为修饰剂,经一步水热合成法,制备出一种具有高荧光强度的氨基功能化碳量子点(BPEI-CQDs)。所合成的荧光碳量子点在365 nm紫外光照射下呈现出明亮的蓝色荧光。通过透射电镜(TEM)观察发现,BPEI-CQDs在水中分散均匀,没有明显团聚现象,其平均粒径约为6.5 nm。拉曼光谱表明,修饰后的碳量子点表面缺陷程度增大。Cu~(2+)可与BPEI-CQDs表面的氨基结合形成铜胺络合物,进而导致碳量子点的荧光猝灭。在0~1μmol/L Cu~(2+)浓度范围内,BPEICQDs的荧光强度与Cu~(2+)浓度呈现出良好的线性关系,检测限可达8.7 nmol/L。     

反应型香豆素N_2H_4荧光探针的生物成像研究

为合成适用于生物监测的水合肼荧光探针,该文基于水合肼诱导乙酰基脱保护生成7-羟基-4-甲基香豆素的原理,设计合成一种具有高灵敏度、高选择性的水合肼荧光增强型有机分子探针。采用光谱学测试及细胞荧光成像的方法,对探针的性能进行表征。实验结果表明:在缓冲溶液中,加入N_2H_4后,探针溶液的荧光光谱在451 nm处产生一个显著的荧光增强峰(33倍),定量分析检测限为9×10-8mol/L(y=20.316 7+25.177 8x,r=0.999 6),与其他测试物相比,探针表现出对N_2H_4较高的选择性和专一性(F水合肼=787,F其他=22~24);此外,细胞内的荧光成像实验,证明该荧光探针具有潜在检测细胞内N_2H_4的能力。     

Zn~(2+)荧光探针活性染料的制备及性能研究

设计合成了两种以水杨醛苯甲酰肼腙为主体的三嗪类活性染料分子,采用红外、核磁共振等技术对分子结构进行表征。采用紫外-可见吸收光谱、荧光光谱对其光学性能和Zn2+检测性能进行了研究,分析了分子结构对Zn2+荧光探针性能的影响与规律,从实验与理论计算分别研究Zn2+荧光探针的机理。发现三嗪类活性染料荧光探针的荧光强度与Zn2+浓度成良好的线性关系,线性范围1~10,0.1~5μmol/L,实际检测限为3,1μmol/L。     

可用于荧光检测硫化氢的希夫碱配合物的设计与合成

以1,8-萘二甲酸酐为起点,合成1,8-萘酰亚胺,通过亲核加成反应合成希夫碱配体,进而与铜离子络合得到配合物,采用核磁共振氢谱与傅立叶变换红外光谱对其进行了结构表征。考察了配合物与H2S气体反应前后紫外吸收光谱与荧光光谱的变化、浓度响应曲线、响应时间,响应在20s开始并于2min完成,检测极限达到1.68μmol/L。配合物对硫化氢有良好的荧光增强响应,具有响应快、灵敏度高、检测极限低的特点。     

新型GSH荧光传感材料的合成与性能研究

以罗丹明B酰肼为荧光发光团,设计并合成了一种带有二硫键的荧光探针RNSS,该探针在乙腈与水溶液（v/v=1∶1）中可以特异性地识别谷胱甘肽（GSH）。通过红外光谱、核磁共振谱图、荧光光谱对探针的结构与性能进行表征与分析。实验结果表明,当向探针溶液中加入GSH后,在561 nm光的激发下,其在585 nm处出现明显的粉色荧光,并且其他氨基酸没有荧光响应,表明其具有良好的专一选择性以及抗干扰能力;同时探针对GSH的检出限为6.063×10^-6 mol/L,说明其具有高灵敏性;经荧光光谱滴定曲线与Job-plot分析可知二者通过二硫键取代反应以1∶1的方式形成配合物。     

Polydimethylsiloxane permeability-based method for the continuous and specific detection of hydrogen sulfide

Hydrogen sulfide (H(2)S) is known to play a physiological role in processes as diverse as vasodilation, maintenance of vascular tone, neurotransmission, and immune response. The multitude of physiological functions in which H(2)S is involved warrants the development of useful methods for its detection. Here, we introduce a simple and continuous H(2)S detection method that exploits the relatively high polydimethylsiloxane (PDMS) permeability of H(2)S in comparison to other thiols typically encountered in the cellular milieu. In this method, 96-well inserts constructed of PDMS act as an H(2)S-permeable membrane, eliminating nonspecific thiol detection. This design also makes it possible to use virtually any available thiol-specific probe such as Ellman's reagent which was used here to detect H(2)S once it crossed the PDMS membrane. Utilizing this method, a detection limit of 9.2 ± 1.9 ppb(m) (parts per billion (by mole) or ~0.51 μM in 1.6 mL of buffer) free H(2)S (detected as solution sulfide) was achieved. In addition, the assay was used to determine K(M) and V(max) for natural substrates of cystathionine γ-lyase (CSE), the main enzyme responsible for H(2)S production in peripheral tissues. The K(M) and V(max) of CSE for cysteine were 3.79 ± 2.07 mM and 0.37 ± 0.02 nmol H(2)S/min, respectively. K(M) and V(max) for homocysteine were 6.90 ± 1.78 mM and 1.10 ± 0.19 nmol H(2)S/min, respectively. In addition, the assay was used to examine the potential for a direct interaction of H(2)S and NO. The levels of detected H(2)S decreased in the presence of NO under normoxia but not under anoxia indicating that H(2)S does not react with NO but with N(2)O(3) likely formed in the hydrophobic environment of PDMS.     

基于Pd/Fe3O4/rGO纳米复合材料的H2O2无酶传感器

环境监测、食品工业、临床、制药等领域对过氧化氢(H_2O_2)的快速、准确检测有极大的需求,而电化学检测方法由于灵敏度高、响应快、检测限低等特点被认为是最理想的H_2O_2检测方法.本文利用电化学沉积的方法将Pd纳米颗粒沉积到四氧化三铁/石墨烯(Fe_3O_4/rGO)纳米复合材料修饰的玻碳电极表面,形成基于新型磁性纳米复合材料的H_2O_2无酶传感器;并采用循环伏安和计时安培电流等方法对修饰电极的电化学性能进行了表征.结果表明:制备的Pd/Fe_3O_4/r GO/GCE对H_2O_2的催化还原显示出较好的电催化活性,Pd纳米颗粒和Fe_3O_4/rGO在催化H_2O_2还原的过程中表现出了良好的协同作用.测定H_2O_2的线性范围为0.05~1 m M和1~2.6 m M两段,最低检测限达到3.918μM(S/N=3).并且该传感器具有较高的灵敏度和较好的重现性和抗干扰性,具有一定的实际应用价值.     

Continuous-flow, on-line monitoring of biospecific interactions using electrospray mass spectrometry

A continuous-flow analytical screening system is presented using electrospray mass spectrometry to measure the interaction of biologically active compounds with soluble affinity proteins. The biochemical detection system is based on a solution-phase, homogeneous assay. In a first step, compounds to be screened (e.g., biotinylated compounds, concentration range 10-1,000 nmol/L) are injected into a continuous-flow reaction system and allowed to react with the affinity protein (e.g., streptavidin, concentration range 3-48 nmol/L). Subsequently, a reporter ligand (fluorescein-labeled biotin 96 nmol/L) is added to saturate the remaining free binding sites of the affinity protein and the concentration of unbound reporter ligand is measured using electrospray MS in the selectedion monitoring mode. The presence of active compounds in the sample results in an increase of the concentration of unbound reporter ligands. The feasibility of a homogeneous MS-based biochemical assay is demonstrated using streptavidin/biotin and anti-digoxigenin/digoxin as model systems. Compared to radioactive or fluorescence-based biochemical assays, the present assay format does not require the synthesis and purification of labels. Various analytical conditions were investigated to determine the ability of MS to measure the biochemical interactions. The availability of a single ligand that can be detected at 10-50 nmol/L concentrations by electrospray MS is sufficient to set up the biochemical assay. For the biospecific interactions studies, detection limits of 10-100 nmol/L were obtained.     

G105钻杆材料多元腐蚀行为研究

通过正交表设计实验,利用高温高压釜腐蚀实验并辅以失重法,研究了温度、Cl-浓度、S2-浓度和HCO3-浓度对G105钻杆材料多元腐蚀行为的影响。采用体视显微镜和SEM观察腐蚀形态和产物膜形貌,同时利用X射线能谱分析仪(EDS)进行产物膜成分分析。结果表明,在实验研究范围内,NaHCO3浓度是最大的影响因素,其次是温度和Na2S浓度,NaCl浓度的影响最小;腐蚀环境严重影响腐蚀速率;在60℃,NaCl浓度为5g/L,Na2S浓度为7g/L以及NaHCO3浓度为1g/L环境下,G105钻杆材料的腐蚀以NaHCO3引起的腐蚀为主;在60℃,NaCl浓度为50g/L,Na2S浓度为30g/L以及NaHCO3浓度为30g/L环境下,G105钻杆材料的腐蚀以Na2S引起的腐蚀为主。     

Electrochemical oxidation of oxalic acid at highly boron-doped diamond electrodes

Electrochemical oxidation of oxalic acid has been investigated at bare, highly boron-doped diamond electrodes. Cyclic voltammetry and flow injection analysis with amperometric detection were used to study the electrochemical reaction. Hydrogen-terminated diamonds exhibited well-defined peaks of oxalic acid oxidation in a wide pH range. A good linear response was observed for a concentration range from 50 nM to 10 microM, with an estimated detection limit of approximately 0.5 nM (S/N = 3). In contrast, oxygen-terminated diamonds showed no response for oxalic acid oxidation inside the potential window, indicating that surface termination contributed highly to the control of the oxidation reaction. An investigation with glassy carbon electrodes was conducted to confirm the surface termination effect on oxalic acid oxidation. Although a hydrogen-terminated glassy carbon electrode showed an enhancement of signal-to-background ratio in comparison with untreated glassy carbon, less stability of the current responses was observed than that at hydrogen-terminated diamond.     

石墨烯/银纳米颗粒复合材料的制备及其对双氧水的电化学检测

以氧化石墨烯(GO)和硝酸银为原材料,聚乙烯吡咯烷酮(PVP)为还原剂和稳定剂,通过水热法制备出还原氧化石墨烯/银纳米颗粒(rGO/AgNPs)复合材料。采用透射电子显微镜(TEM)、X射线衍射(XRD)及紫外-可见分光光度计(UV-Vis)对rGO/AgNPs复合材料的形貌、组成和结构进行表征。同时,将rGO/AgNPs复合材料修饰到玻碳电极表面制备出过氧化氢(H_2O_2)电化学传感器,通过循环伏安法(CV)和计时安培响应法(i-t)对传感器进行电化学性能测试。实验结果表明:制备的rGO/AgNPs传感器具有较好的电化学性能,其对H_2O_2检测的灵敏度为340.6μA·(mmol/L)~(-1)·cm~(-2),响应时间为3s,最低检测极限为7.5μmol/L(S/N=3),线性检测范围为20~4950μmol/L(线性相关系数为R=0.9973)。     

Electrochemically reduced graphene modified carbon ionic liquid electrode for the sensitive sensing of rutin

In this paper a graphene (GR) modified carbon ionic liquid electrode that was obtained by one-step potentiostatic electroreduction of a graphene oxide solution was described. The resulting electrode displayed excellent electrochemical performance due to the formation of highly conductive GR film on the electrode surface. Electrochemistry of rutin was carefully studied with a pair of well-defined redox peaks appeared in pH 2.5 buffer solution. Rutin exhibited a diffusion-controlled two-electron and two-proton transfer reaction on the modified electrode with the electrochemical parameters calculated. The reduction peak currents are linearly related to rutin concentration in the concentration range from 0.070 to 100.0 μmol/L with a detection limit as low as 24.0 nmol/L (3σ). The modified electrode displayed excellent selectivity with good stability, and was applied to the determination of rutin content in tablet, human serum and urine samples with satisfactory results.     

Room temperature synthesis and electrochemical application of imidazoline surfactant-modified Ag2S nanocrystals

Well-dispersed Ag₂S nanocrystals with size of about 20~30 nm were prepared in distilled water at room temperature with the assistance of imidazoline surfactant quaternary ammonium salt of 2-undecyl-1-dithioureido-ethyl-imidazoline (SUDEI) prepared in-house. The products were characterized by TEM, XRD, and FT-IR, respectively. The influence of SUDEI concentration on the dispersion of Ag₂S products was briefly discussed. Furthermore, the obtained Ag₂S nanocrystals product was applied into DNA hybridization analysis, and the results indicated that the detection limit of target ssDNA was up to pmol/L, showing that the DNA probe labeled with Ag₂S nanoparticles is of promising application value in electrochemical DNA detection analysis and biosensors.     

金属—PAN—S配合物的极谱研究——Ⅱ:Fe~(3+)—PAN—S—TEA—NH_3·H_2O—NH_4Cl体系配合吸附波

在NH_3·H_2O—NH_4Cl—三乙醇胺底液中Fe(Ⅲ)与PAN—S产生一灵敏的配合吸附波,峰电位在—0.50伏(vs.SCE)。峰电位与铁离子浓度在2.8×10~8～3.4×10~(-6)mol/L范围内线性良好,检出下限可达2.8×10~(-8)mol/L。该法用于乳粉、头发、血清等样品的测定,结果满意。     

Cyanuric acid trace analysis by extractive methylation via phase-transfer catalysis and capillary gas chromatography coupled with flame thermoionic and mass-selective detection. Process parameter studies and kinetics

A GC method using phase-transfer catalysis for the simultaneous derivatization, extraction, and preconcentration of the highly polar cyanuric acid (CYA) was developed. The method was based on the extractive N-methylation of the analyte of concern in two- and three-phase systems, whereby the 1,3,5-trimethyl-1,3,5-triazine-2,4,6-(1H,3H,5H)trione was formed. Subsequent detection was performed using flame thermoionic specific detection (FTD) and mass spectrometry (MS) selective-ion monitoring (SIM) using electron impact. The optimal experimental conditions related to pH, kind of catalyst and solvents, methyl iodide concentration, phase volumes, reaction time, temperature, and agitation were suitably established. Inter alia, the resulting method is highly sensitive, almost free from interferences, and was easily applied to the determination of cyanuric acid in swimming pool water, surface water, human urine, and simulated air filter samples. The minimal quantitable concentration was found to be less than 1 and 90 microg L(-1) using GC-MS-(SIM) and GC-FTD, respectively. The overall precision for the workup procedure did not exceed 3.6% (n = 6) for 5.0 microg L(-1) CYA-spiked urine and river water while the respective value for the same matrixes spiked at a concentration of 200 microg L(-1) was calculated to be in the range 1.9-4.0% (n = 6). The overall recovery from spiked samples was 98 +/- 5% for microgram per liter levels of CYA. A kinetic study conducted was helpful to get a better insight into the N-methylation reaction mechanism.