Preparation and application of electrochemical barbital sensor based on molecularly imprinting technique

A molecularly imprinted electrochemical sensor was prepared based on poly folic acid(PFA) for rapid detection of barbital(BAR). The PFA membrane was obtained via directly electropolymerization technique on the surface of chemically modified Au electrode(Au/CME) by means of cyclic voltammetry(CV) in the potential range between-0.4 and 1.0 V in phosphate buffer solution(PBS) pH 7.04. The molecularly imprinted polymers(MIP) membrane was synthesized with BAR as template molecules and folic acid(FA) as the functional monomer. The performance and surface feature of the proposed imprinted sensor were investigated using CV, differential pulse voltammetry(DPV), electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). Under the optimized conditions, the peak current decrease(ΔI_p) was proportional to the BAR concentration in the range of 1.00×10~(–7)-1.00×10~(–4) mol/L(R~2=0.998 2) with a detection limit(S/N=3) of 4.65×10~(–8) mol/L. The results indicated that the imprinted sensor exhibited an excellent selectivity for BAR and it was successfully used to determine BAR in real samples with recoveries of 94.7%-106.2% by using the standard addition method.     

Neuropeptide Y receptors in a protozoaStylonychia mytilus

Radio ligand binding assays(RLBA) were used to study neuropeptide Y (NPY) receptors in a protozoa Stylonychia mytilus. The experimental results showed that 2-3×10+3/mL Stylonychia cells incubated in Pringsheim solution which contained 3H-NPY could specifically bind 3H-NPY and concomitantly present saturable characteristic. This suggested that Stylonychia possessed some specific binding sites for NPY. Scatchard transformations of binding assay for the NPY receptors at 25℃ are compatible with the specific activity of 42.47 fmol/10+3 cells and the binding equilibrium constant of 0.113 nmol/L. The data of 125I-NPY binding assay to the membrane protein extract of Stylonychia indicated that there was a significant difference between the amount of total bound and nonspecific bound of 125I-NPY. This result indicated that NPY receptors were probably localized mainly on the cell membrane.     

THE TRANSFER BEHAVIOUR OF SOME CATIONS AT WATER／NITROBENZENE INTERFACE BY SEMIDIFFERENTIAL CYCLIC VOLTAMMETRY

The transfer of Sr~(2+) and Ba~(2+) ion, facilitated by 18-Crown-6 present in the aqueous phase, and of succinylcholine ion at w/nb interface were investigated by semi-differential cyclic voltammetry. A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl (w)——0.01 mol/l TBATPB (nb). The peak current is directly proportional to the concentration of SC~(2+) ion. It can be used for the determination of SC and the detection limit is 1.05×10~(-5) mol/l.The apparent D~w and D~(nb) have been estimated. The transfer of Sr~(2+) and of Ba~(2+) at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water. This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.     

Trace determination of zirconium using anodic adsorptive voltammetry at a carbon paste electrode modified with multi-walled carbon nanotubes

A carbon paste electrode modified with multi-walled carbon nanotubes （MWCNT） was prepared and the determination of ultra trace amount of zirconium based on the anodic adsorptive voltammetry of the zirconium-calcium-alizarin red S mix-polynuclear complex is described in this paper for the first time. The results showed that the sensitivity and the selectivity of the method are excellent. The second derivative linear scan voltammograms of the complex were recorded by polarographic analyzer from 200 to 1200 mV （vs. SCE） and it was found that the complex can be adsorbed on the surface of the electrode, yielding a peak at about 840 mV, corresponding to the oxidation of ARS in the complex. The peak current increases linearly with Zr （IV） concentration in the range of 6.0×10^-12--6.0×10^-11 mol. L^-1 （accumulation time 120 s）, 6.0×10^-11--2.0×10^-9 mol. L-1 （accumulation time 90 s） and 2.0×10^-9--1.0×10^-7 mol. L^-1 （accumulation time 60 s） and the detection limit （S/N = 3） is 2.0×10^-12 mol. L^-1 （accumulation time 180 s）. The procedure has been successfully applied to the determination of zirconium in the ore samples.     

Nonlinear Analyses of the Dynamic Properties of Hydrostatic Bearing Systems

Nonlinear analyses of hydrostatic bearing systems are necessary to adequately model the fluid-solid interaction. The dynamic properties of linear and nonlinear analytical models of hydrostatic bearings are compared in this paper. The analyses were based on the determination of the aperiodic border of transient processes with external step loads. The results show that the dynamic properties can be most effectivelyimproved by increasing the hydrostatic bearing crosspiece width and additional pocket volume in a bearing can extend the load range for which the transient process is aperiodic, but an additional restrictor and capacitor (RC) chain must be introduced for increasing damping. The nonlinear analyses can also be used to predict typical design parameters for a hydrostatic bearing.     

Optimizing the fabrication of carbon nanotube electrode for effective capacitive deionization via electrophoretic deposition strategy

In order to obtain superior electrode performances in capacitive deionization(CDI), the electrophoretic deposition(EPD) was introduced as a novel strategy for the fabrication of carbon nanotube(CNT) electrode.Preparation parameters, including the concentration of slurry components, deposition time and electric field intensity, were mainly investigated and optimized in terms of electrochemical characteristic and desalination performance of the deposited CNT electrode. The SEM image shows that the CNT material was deposited homogeneously on the current collector and a non-crack surface of the electrode was obtained. An optimal preparation condition of the deposited CNT electrode was obtained and specified as the Al(NO3)3 M concentration of 1.3 × 10~(-2) mol/L, the deposition time of 30 min and the electric field intensity of 15 V/cm. The obtained electrode performs an increasing specific mass capacitance of 33.36 F/g and specific adsorption capacity of 23.93 mg/g, which are 1.62 and 1.85 times those of the coated electrode respectively. The good performance of the deposited CNT electrode indicates the promising application of the EPD methodology in subsequent research and fabrication of the CDI electrodes for CDI process.     

Nanostructured multilayer thin films of multiwalled carbon nanotubes/gold nanoparticles/glutathione for the electrochemical detection of dopamine

In the present study, multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs), and glutathione (GSH) were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly(diallydimethylammonium chloride) to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuNPs. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 μmol/L. The limits of detection and quantitation of dopamine are (0.316±0.081) μmol/L and (1.054±0.081) μmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.     

DIFFERENTIAL PULSE VOLTAMMETRIC DETERMINATION OF 3,3''''5,5''''-TETRAMETHYLBENZIDINE AND ITS ANALOGUES WITH A GLASSY CARBON ELECTRODE

The differential pulse voltammetric (DPV) method-with a glassy carbon electrode was used for the determination of 3,3' 5,5'-tetramethy lbenzidine (TMB), o-tolidine and benzidine in the acidic media. The pulse amplitude, interval time and scan rate of DPV are optimized to be 50 mV, 0. 5 s and 10 mV/s, respectively. The peak current, is proportional to the concentration of TMB and its analogues, the linear range is from 10~(-6)mol/l to 10~(-4)mol/l. The electrochemical behaviour of the compounds is discussed. The chemical poisons can be determined directly, or indirectly by the extraction in the waste water of chemical industry and laboratory.     

Wire-like nano-polyaniline deposited electrochemically in a reverse micelle electrolyte as a p H sensor

Wire-like polyaniline(PANI) films were successfully electrodeposited onto an indium tin oxide(ITO) substrate using a pulse galvanostatic method(PGM) in a reverse micelle electrolyte. The as-prepared PANI films were electrochemically analyzed by cyclic voltammetry and electrochemical impedance spectroscopy in 1 mol·L-1 HCl O4 solution. It is found that the as-prepared PANI films are highly porous, exhibit the diameters of approximately 100 nm and the lengths exceeding 3 μm, and have favorable electrochemical activities. Furthermore, the as-prepared wire-like PANI films show a good linear relationship of the potentiometric response curve over the p H value range of 3–10 with a slope of 74.13 m V·p H-1 in 0.5 mol·L-1 K2HPO4 basal solutions. The results demonstrate that the prepared wire-like PANI films are promising p H sensors.     

Directional solidification and physical properties measurements of the zinc-aluminum eutectic alloy

Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates (5.32–250.0 μm/s) at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus. The values of eutectic spacing were measured from transverse sections of the samples. The dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53, respectively. The results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the literature. Microhardness of directionally solidified samples was also measured by using a microhardness test device. The dependency of the microhardness on growth rate is found as Hv=115.64V0.13. Afterwards, the electrical resistivity (r) of the casting alloy changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300–630 K. The enthalpy of fusion (ΔH) and specific heat (C_p) for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/(g·K), respectively by means of differential scanning calorimetry (DSC) from heating trace during the transformation from liquid to solid.     

PVC膜碘离子选择电极的研制与应用

以三辛基十二烷基碘化铵（ＤＴＯＡ—Ｉ）为电活性物，邻苯二甲酸二丁酯（ＤＢＰ）为增塑剂，制成聚氯乙烯（ＰＶＣ）膜碘离子选择电极。电极对Ｉ－浓度在８．０×１０－６～１．０×１００ｍｏｌ·Ｌ－１范围内符合能斯特响应，其斜率为５７．０ｍＶ／ｐＩ－（１６℃）。用该电极测定了海盐中微量碘，回收率在９３．２２％～１０５．３％之间。     

碘化物的光分析研究进展

总结了90年代以来国内外有关碘化物光分析的进展。主要内容包括：分光光度法、荧光法、化学发光法以及分离手段、流动注射技术与上述检测方法的联用，并且对碘化物光分析方法的应用前景提出展望。     

以碘丙烯为中间体合成螺恶嗪

以碘丙烯为中间体合成了N-丙烯基-3，3-二甲基螺吲哚啉-2，3’-[3H]萘并[2，1-b][1，4]噁嗪。对产物用IR，^1HNMR进行了表征，讨论了N-丙烯基-3，3-二甲基螺吲哚啉-2，3’-[3H]萘并[2，1-b][1，4]噁嗪的洗涤及提纯方法。     

溶胶-凝胶膜修饰的碘离子选择性电极

用溶胶-凝胶包埋硝酸银制备碘离子选择性电极。该电极对I-浓度在10-1~10-7mol/L范围内呈Nernst响应,反应斜率为58.321mV/pI-,检测下限为4.6×10-8mol/L,回收率为97.4%~103.2%。     

丁二酮肟分光光度法测钴方法的研究

以丁二酮肟 (DMG)为显色剂与 Co2＋显色反应,生成二元有色络合物,在二元有色络合物基础上再与碘离子形成三元有色络合物,增大有色物质的对单色光吸收能力,提高显色反应的灵敏度.着重系统研究显色反应的影响因素（络合剂用量、温度、酸度、时间）对显色效果的影响,并确定最佳显色参数：λ max=347 nm,ε =1.4× 104 L× mol－ 1× cm－ 1, pH=5～ 7.线性范围 1.0～ 15 ug/mL,三元有色络合物组成为 Co(DMG)2I2.     

二氧化碳气体浮选分光光度测定食盐中微量碘的研究

提出以二氧化碳气体为浮选剂．将碘与溴化十六烷基三甲基铵[cTMAB]形成的离子缔合物     

溶剂浮选吸光光度法测定高碘蛋中总碘量

浮选法是在二氧化碳气氛中，以溴化十六烷三甲基铵（ＣＴＭＡＢ）为捕收剂，用溶剂浮选吸光光度法，对离子缔合物（ＣＴＭＡ＋Ｉ－３）的组成进行测定．实验表明，方法有较高的灵敏度，较好的准确性和重现性     

碘化锂在有机合成中的应用

就碘化锂在有机合成中的新进展，如碘代反应、裂解反应、Ｃ－Ｃ键的形成、还原反应以及其它反应进行了综述．     

利用高压釜合成烷基咪唑碘及在太阳电池中的应用

利用高压釜在无溶剂的条件下合成了离子液体1-甲基-3-丙基咪唑碘、1-甲基-3-己基咪唑碘.结果表明利用高压釜来提高反应温度,使1-甲基咪唑和碘代烷烃按化学计量比进行反应,产率近100%.该方法所得产品纯度高,操作简单无污染,实现了离子液体的绿色合成.另外,将这两种离子液体配制成电解质并组装成染料敏化太阳电池,测量了其光伏性能参数.