空心纳米金在甲醛气体传感器中的应用研究

通过牺牲模板法合成了具有空心结构的纳米金催化剂,并进行了TEM、 SEM和XRD等物理表征.把该催化剂作为工作电极的活性物质,以1 mol/L KOH为电解质,组装了电流型甲醛气体传感器.在甲醛气体浓度为0～2.23×10-6 mol/L范围内对传感器进行了性能测试,传感器响应信号y(A)与气体浓度x(mol/L)线性回归方程为y=16.63x+4.063×10-7, r=0.9989.该传感器灵敏度高于同载量实心金纳米催化剂组装的传感器70%左右,达到了降低贵金属用量的目的.因其具有较快的响应时间、 良好的重现性和良好的线性关系等优点,可用于适当浓度范围内的甲醛气体检测.     

用于测定空气中甲醛的电子鼻

制作了可定量检测空气中甲醛的便携式电子鼻.该电子鼻由传感器阵列、信号调理电路、模式识别系统以及显示系统等4个部分组成,其中传感器阵列为4个半导体金属氧化物传感器.模式识别系统采用模糊神经网络算法.便携式甲醛电子鼻对甲醛气体响应专一,抗干扰能力强,且定量结果精确,可用于甲醛气体的现场检测.对于0.001～0.25mg/L浓度范围内的甲醛气体,电子鼻定量测报的正确率达到81.3%;对于干扰气体存在下的甲醛气体,未出现错误测报.     

新型甲醛多孔硅复合传感器的制备

构建了一种简便、快速检测甲醛的新型钯-多孔硅(Pd-PS)复合传感器.采用水热腐蚀法制备多孔硅,通过扫描电镜表征其表面微结构.对多孔硅腐蚀条件进行了优化,得出多孔硅的最佳制备条件.多孔硅经化学浸渍法在其表面掺杂金属钯,进而制成了钯-多孔硅复合传感器.当此传感器被置于含甲醛的混合气体中时,可高选择性结合甲醛气体分子,并产生电信号,其强度与甲醛浓度相关,通过万用表检测其电信号,进而分析其气敏性能.检测结果表明,此传感器对甲醛气体敏感,且表现出良好的选择性,对乙醇、氨气、甲醇和丙酮不敏感.此传感器对甲醛浓度的检测范围在0.1～ 6.0 mg/m3之间,检出限为0.1 mg/m3,检测时间为3 min.     

树枝状纳米银颗粒的制备与电活性

在Ag(NH3)2+溶液中,在钛基体上电沉积出树枝状纳米银颗粒,研究了沉积电位对树枝状纳米银颗粒形成的影响,探讨了这种树枝状纳米银颗粒形成的机理,并研究了这种钛基树枝状纳米银电极(Ag/Ti)在碱性溶液中对甲醛氧化的电催化活性。结果表明,在30 mmol/LAg(NH3)2+以及沉积电位在-1.8～-1.2 V(vsAg)时,形成了形态为树枝状的纳米银颗粒。在沉积电位为-1.6 V(vs Ag),Ag(NH3)2+浓度为30 mmol/L的溶液中,电沉积制备的这种树枝状纳米银电极(Ag/Ti)对甲醛氧化具有强的电催化活性。循环伏安曲线表明,在0.1 mol/LNaOH溶液中以及甲醛的浓度范围在0～40 mmol/L,甲醛浓度和它的氧化峰电流密度呈现良好的线性关系,检测下限达到0.662 mmol/L,这种新型的树枝状纳米银电极有望作为甲醛检测的传感器。     

基于铂薄膜电极的电化学型甲醛传感器

制做了液相体系中以铂薄膜电极作为工作电极的甲醛电化学传感器。利用X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)对铂薄膜电极的物相和表面形貌进行表征。在外加电压为0.7 V,电解液H2SO4溶液浓度为0.1mol/L时,传感器的响应信号与甲醛浓度在0.561~18.71μmol/L之间呈现良好的线性关系,线性方程为Y=0.4085c+2.746(R2=0.9904),传感器对甲醛的响应时间(T 90)约为60 s。     

基于铂微粒和Nafion膜修饰玻碳电极的甲醛传感器

通过在Nafion膜修饰玻碳电极表面电沉积铂微粒制备了甲醛电化学传感器(Pt/Nafion/GCE)。利用循环伏安法研究了甲醛在该传感器上的电化学行为,优化了实验参数,在此基础上建立了用伏安法直接测定甲醛的新方法。在酸性溶液中,甲醛的氧化峰电流与其浓度在1.0×10-6~1.0×10-3mol/L的范围内呈良好的线性关系(r=0.9995),检出限为5.0×10-7mol/L。本文所提出的测定甲醛的方法具有较高的灵敏度和较好的重现性。     

基于纳米二氧化锆与铂微粒复合修饰玻碳电极的甲醛传感器研究

采用循环伏安法在玻碳电极表面依次电沉积纳米二氧化锆和铂微粒,制备了一种检测甲醛的新型电化学传感器。用电镜扫描对该修饰电极表面进行了表征,循环伏安法和线性扫描伏安法研究了甲醛在该修饰电极上的电催化氧化作用,优化了实验参数。结果表明,该修饰电极对甲醛有很好的电催化氧化作用,在0.1 mol/L H2SO4溶液中,甲醛的氧化峰电流与其浓度在1.0×10-6~5.0×10-3mol/L范围内呈良好线性关系,回归方程为Ip(μA)=79.95+2.005×105c(mol/L),相关系数r=0.999 3,检出限为5.0×10-7mol/L。     

基于石墨烯/Pd纳米粒子复合材料的甲醛传感器的研究

采用硼氢化钠常温一步还原法制备了石墨烯/Pd纳米粒子,以此复合纳米材料修饰玻碳电极为传感界面构建了一种新型的甲醛传感器。循环伏安法和计时电流法研究显示,在碱性条件下(0.1 mol/L KOH溶液),此传感器对甲醛有较好的电催化氧化作用。甲醛在4.0×10-4~5.3×10-3mol/L浓度范围内存在良好的线性关系,相关系数R=0.9934,检出限是1.3×10-4mol/L。     

甲醛电化学传感器多孔气体扩散电极不同催化层结构与响应性能研究

多孔气体扩散电极的制备是制备甲醛电化学传感器的关键所在, 其中催化层的结构直接影响到传感器的响应性能. 通过柠檬酸三钠还原法合成了纳米金-活性炭、纳米金-碳纳米管催化剂, 制备了甲醛电化学传感器多孔气体扩散电极, 并对电极进行SEM(扫描电子显微镜)物理表征. 在甲醛气体浓度为0.24和0.63 mg/m³时, 电极C具有较好的响应, 在0.1到0.84 mg/m³浓度范围内, 线性方程为y＝10.515x＋4.4049 (R²＝0.9917), 响应时间约80 s. 分析了不同催化剂的气体扩散电极结构与甲醛响应性的关系, 为研制开发性能优良的甲醛电化学传感器奠定了基础.     

一种新型连续检测镉离子和焦磷酸阴离子的逻辑门荧光传感器及其细胞成像研究

设计并合成了一种基于8-羟基喹啉(8-HQ)的连续检测Cd~(2+)和焦磷酸阴离子(PPi)的荧光传感器L.在传感器L的DMSO/H2O(V/V=1/1,0.01mol/L,Hepes-HClbuffer,pH=7.20)溶液中加入Cd~(2+)后导致荧光发射峰(Em=537 nm)猝灭,检测限低至5.87×10~(-8) mol/L.通过Job's曲线图和质谱验证传感器L和Cd~(2+)离子之间以1∶1化学计量比结合,结合常数为4.38×10~4 L/mol.复合传感器L-Cd~(2+)体系具有通过配体置换法对PPi高度选择性检测性能. L可以作为一种逻辑门荧光传感器检测Cd~(2+)和PPi.传感器L可以用于对活细胞中的Cd~(2+)和PPi的荧光成像.     

基于纳米铁氰化镍修饰二氧化钛纳米管阵列电极的非酶葡萄糖传感器

以二氧化钛纳米管阵列(TNTs)为基底,利用脉冲电沉积的方法将Ni纳米粒子沉积在TNTs管内,通过循环伏安法将Ni转化为铁氰化镍(NiHCF),构造了新型的非酶型葡萄糖生物传感器(NiHCF/TNTs修饰电极)。在优化的实验条件下,传感电极的灵敏度为663μA/(mmol cm2);响应电流与葡萄糖浓度在1～23mmol/L范围内呈现良好的线性关系。在低浓度检测下,线性范围为2×10-3～1.0 mmol/L;检出限为0.5μmol/L。本传感电极具有灵敏度高、稳定性好和抗干扰能力强等特点。     

黄芩及其制剂中黄芩素和黄芩甙的

用毛细管区带电泳 -电化学检测法测定了黄芩及其制剂中黄芩素和黄芩甙的含量。研究了电极电位、电解液酸度和浓度、电泳电压及进样时间等对电泳的影响 ,得到了较为优化的测定条件。以直径为300μm的碳圆盘电极为检测电极 ,电极电位为0.90V(vsSCE) ,在100mmol/L硼酸盐缓冲液(pH9.0)中 ,上述两组分在8min内完全分离。黄芩素和黄芩甙浓度与电泳峰电流分别在5.0×10 -7～1.0×10 -3mol/L和1.0×10 -6～1.0×10 -3mol/L范围内呈良好线性 ,检出限分别为2.24×10 -7mol/L和5.48×10 -7mol/L。7次测定分别含5.0×10 -4mol/L黄芩素和黄芩甙试样溶液 ,峰高的相对标准偏差分别为3.53%和4.03%。     

High-Sensitive Glucose Biosensor Based on Ionic Liquid Doped Polyaniline/Prussian Blue Composite Film

The Prussian blue/ionic liquid-polyaniline/multiwall carbon nanotubes (PB/IL-PANI/MWNTs) composite film was fabricated by using cyclic voltammetry. The ion liquid acting as a lubricating agent, could enhance the electron delocalization degree and reduce the struc-tural defects of the polyaniline. The surface morphology of the composite film revealed that the PB nanoparticles have smaller size than that in pure PB film. Due to the introduction of ion liquid, the PB/IL-PANI/MWNTs composite film showed wonderful synergistic effect which can remarkably enhance sensitivity, expand linear range and broaden acidic adapt-ability for hydrogen peroxide detection. The composite film demonstrated good stability in neutral solution contrast to pure PB film, with a linear range from 2.5 μmol/L to 0.5 mmol/Land a high sensitivity of 736.8 μA·(mmol/L)^-1·cm^-2 for H₂O₂ detection. Based on the com-posite film, an amperometric glucose biosensor was then fabricated by immobilizing glucose oxidase. Under the optimal conditions, the biosensor also exhibits excellent response to glucose with the linear range from 12.5 μmol/L to 1.75 mmol/L and a high sensitivity of 94.79 μA (mmol/L)^-1·cm^-2 for H₂O₂. The detection limit was estimated 1.1 μmol/L. The resulting biosensor was applied to detect the blood sugar in human serum samples without any pretreatment, and the results were comparatively in agreement with the clinical assay.     

Electrochemical determination of lead using bismuth modified glassy carbon electrode

Electrochemical application of bismuth film modified glassy carbon electrode was studied with the objective of lead detection. Bismuth film on glassy carbon substrate was formed in a plating solution of 2 mmol/L Bi(NO₃)₃, in 1 mol/L HCl at ?1.1 V (vs. Ag/AgCl) for 300 s. Lead was detected by differential pulse anodic voltammetry in acetate buffer of pH 5.0 in the concentration range of 7.5 nmol/L to 12.5 μmol/L. Factors influencing the anodic stripping performance, including deposition time, solution pH, Bi(III) concentration, potential, pulse amplitude, pulse width, have been optimized. Three linear calibration plots in the range 7.5 nmol/L to 0.1 μmol/L, 0.25 to 1 μmol/L, 2.5 to 12.5 μmol/L with regression coefficients of 0.991, 0.986 and 0.978 respectively were obtained. The theoretical detection limit equivalent to three times standard deviation for 7.5 nmol/L lead (n = 5) was calculated to be 5.25 nmol/L utilizing a 5 min deposition time and sensitivity 83.97 A L/mol. The sensitivity and detection limit of the method was compared with reported voltammetric methods for detection of lead and the result obtained was found to be promising for determination of lead.     

纳米金-还原氧化石墨烯修饰葡萄糖氧化酶传感器的制备及其电流法检测饮料中的葡萄糖

利用纳米金(Au NPs)与还原氧化石墨烯(rGO)复合纳米材料制备了葡萄糖氧化酶生物传感器并用于饮料中葡萄糖含量的检测。将壳聚糖作为还原剂及稳定剂,通过一步法合成了Au NPs-rGO复合材料,并通过物理吸附固定葡萄糖氧化酶(GOx)来制作GOx生物传感器。该传感器在磷酸盐缓冲溶液(0.1 mol/L,p H6.0)中,-0.45 V(vs.Ag/Ag Cl)电位下电流法检测葡萄糖含量,线性检测范围为0.01~0.88 mmol/L,灵敏度为22.54μA·mmol-1·L·cm-2,检出限为1.01μmol/L,且表观米氏常数为0.497 mmol/L。该传感器用于多种饮料中葡萄糖含量的直接检测,结果满意。     

Determination of fluoroacetate and fluoride in blood serum by capillary zone electrophoresis using capacitively coupled contactless conductivity detection

Fluoroacetate is a highly toxic species naturally found in plants and in commercial products (compound 1080) for population control of several undesirable animal species. However, it is non-selective and toxic to many other animals including humans, and thus its detection is very important for forensic purposes. This paper presents a sensitive and fast method for the determination of fluoroacetate in blood serum using capillary electrophoresis with capacitively coupled contactless conductivity detection. Serum blood samples were treated with ethanol to remove proteins. The samples were analyzed in BGE containing 15 mmol/L histidine and 30 mmol/L gluconic acid (pH 3.85). The calibration curve was linear up to 75 μmol/L (R2 =0.9995 for N=12). The detection limit in the blood serum was 0.15 mg/kg, which is smaller than the lethal dose for humans and other animals. Fluoride, a metabolite of the fluoroacetate defluorination, could also be detected for levels greater than 20 μmol/L, when polybrene was used for reversion of the EOF. CTAB and didecyldimethylammonium bromide are not useful for this task because of the severe reduction of the fluoride level. However, no interference was observed for fluoroacetate.     

Sol—Gel Derived Carbon Ceramic Electrode Bulk—Modified with Tris（1,10—phenanthroline—5,6—dione） iron （Ⅱ）Hexafluorophosphate and Its Use as an Amperometric Iodate Sensor

A surface‐renewable tris(1, 10‐phenanthroline‐5, 6‐dione) iron (D) hexafluorophosphate (FePD) modified carbon ceramic electrode was constructed by dispersing FePD and graphite powder in methyltrimethoxysilane (MTMOS) based gels. The FePD‐modified electrode presented pH‐dependent voltammetric behavior, and its peak currents were diffusion‐controlled in 0.1 mol/L Na₂SO₄ + H₂SO₄ solution (pH = 0.4). In the presence of iodate, dear electrocatalytic reduction waves were observed and thus the chemically modified electrode was used as an amperometric sensor for iodate in common salt. The linear range, sensitivity, detection limit and response time of the iodate sensor were 5 × 10^?6–1 × 10^?2 mol/L, 7.448 μA·L/ mmol, 1.2 × 10^?6 mol/L and 5 s, respectively. A distinct advantage of this sensor is its good reproducibility of surface‐renewal by simple mechanical polishing.     

微流控芯片测定盐酸地芬尼多片中盐酸地芬尼多

利用微流控芯片非接触电导检测法测定片剂中盐酸地芬尼多的含量.采用1 mmol/L HAc+2 mmol/L NaAc(pH 4.5)为缓冲溶液,0.2 mmol/L 十二烷基硫酸钠(SDS)为添加剂,在分离电压为2.20 kV,进样时间为10 s下,1 min内实现组分快速分离和检测.盐酸地芬尼多线性范围为5～160 ...