Electrochemical Determination of Dicofol at Nickel Nanowire Modified Poly(p‐aminophenol) Film Electrode

An electrochemical sensor was fabricated by construction of nickel nanowires on the surface of poly(p‐aminophenol) (PPAP) modified glassy carbon electrode. The electrochemical response of dicofol, a known pesticide and used for agricultural activities such as cyclic voltammetry and differential pulse voltammetry, were investigated and the results were compared with those obtained unmodified electrodes. Following the optimization of NaOH concentration, polymerization cycle number, Ni nanowire amount, the linear range for the dicofol was studied and found as 0.83–30.7 μmol L^?1 (R²=0.9981) at Ni/PPAP/GCE with a 0.08 μmol L^?1 detection limit according to S/N=3. Finally, the proposed Ni/PPAP/GCE sensor was successfully applied for the dicofol analysis in soil samples. The characterization of the developed surface was carried out by scanning electron microscopy and X‐Ray photoelectron spectroscopy.     

L-半胱氨酸自组装膜修饰电极对对氨基酚电催化氧化及其分析应用

在裸金电极上制备了L 半胱氨酸自组装膜修饰电极(L Cys/AuSAMs),研究了对氨基酚(p AP)在L Cys/AuSAMs上的电化学行为,发现该膜电极对p AP的氧化具有良好的电催化作用。氧化峰电位降低了128mV,测得p AP的扩散系数D为1.27×10-6cm2·s-1,初步探讨了电催化机理。采用水平衰减全反射 傅立叶变换红外光谱(ATR FTIR)技术对L Cys/AuSAMs进行了表征;方波伏安法(SquareWaveVoltammetry,SWV)测定p AP,其氧化峰峰电流与p AP浓度在1.0×10-8～8.0×10-8mol·L-1和1.0×10-7～2.0×10-4mol·L-1范围内呈线性关系,相关系数分别为0.9978和0.9977,检出限为2.0×10-9mol·L-1。该电极用于模拟废水样的测定,结果满意。     

Electrosynthesis of a Net-like Microstructured Poly(p-aminophenol) Film Possessing Electrochemical Properties in a Wide pH Range

Electrochemical polymerization of p-aminophenol in aqueous sulfuric acid solution has been carried out at a platinum foil using repeated potential cycles at the range of ?0.20 to 0.95 V (vs. SCE). The resulting polymer has good electrochemical activity and a fast charge transfer characteristic in the solutions of 0.5 mol dm^?3 Na₂SO₄ with pH ≤ 9.0. Based on the spectroscopic measurements, a possible chemical structure of the resulting polymer was proposed. IR and XPS spectra indicate that SO₄ ^2? ions are contained in the resulting polymer. The scanning electron microscopy (SEM) micrograph proves that the net-like microstructure of the poly(p-aminophenol) film, which is a macroporous network composed of interwoven and coalescing fiber diameters of 100–500 nm and pore diameters of 500 nm–3 μ m, can be prepared using the electrochemical method.     

对氨基苯酚生产新工艺

以对硝基苯酚为原料，铁粉作还原剂一步反应生产对氨基苯酚．采取对母液除硫和减少水用量及降低结晶温度等方法，使产品得率从40％提高到65％以上，产品的各项指标均达到规定标准，获得较好的经济效益。     

The reaction of hexachlorocyclotriphosphazatriene with P-aminophenol

The reaction of hexachlorocyclotriphosphazatriene (1) with p-aminophenol (2) produced two new products: the open chain compound N₃P₃Cl₅(NHC₆H₄OH) (3), and the bridged compound N₃P₃Cl₅(NHC₆H₄O)N₃P₃Cl₅(4). The compounds 3 and 4 were separated and characterized by elemental analysis, massspectrometry and NMR spectroscopy. The molecular structures of compounds 3 and 4 were determined by X-ray crystallography. Compound 3 is the first example of cyclotriphosphazene including (p-hydroxyphenyl) amino group and compound 4 was the first example of the N-substituted p-aminophenoxy group with cyclotriphosphazene.     

对氨基苯酚在石墨烯-离子液体复合物修饰电极上的电化学行为研究

使用石墨烯(Graphene,GR)和离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM] PF6)作修饰剂,通过壳聚糖(CHIT)成膜,制备了石墨烯-离子液体复合物修饰电极([BMIM] PF6 - GR - CHIT/GCE).在0.1 mol/L磷酸盐缓冲液中,采用循环伏安和微分脉冲伏安法研究了对氨基苯酚在[...     

An improved ELISA for the determination of southern bean mosaic virus with linear sweep voltammetry detection based on new system of PAP-H_2O_2-HRP

An improved enzyme-linked immunosorbent assay (ELISA) for the determination of southern bean mosaic virus (SBMV) with linear sweep voltammetry based on a new system of p-aminophenol (PAP)-H2O2-horseradish peroxidase (HRP) has firstly been developed. The enzymatic product 3-[(4-hydrox-yphenyl) amino]-4-(2-amino-5-hydroxyphenyl)-6-[ (4-hydrox-yphenyl)imino]-2,4-cyclohexadiene-l-one, produced from the oxidation of PAP with H2O2 catalyzed by HRP, yielded a sensitive linear sweep voltammetric response at - 0.45 V ( vs. SCE) in Britton-Robinson (BR) buffer solution. Based on the voltammetric peak, HRP can be measured with a detection limit of 0.4 mU/L and a linear range of 1.0-1.0 × 102 mU/ L. The detection limit for the SBMV is 8.0 ng/mL and the highest dilution ratio for the detection of infected leaf sap is 1: 1.5×105.     

Second Derivative Spectrophotometric Determination of p-Aminophenol in the Presence of Paracetamol

Abstract

A second derivative spectroscopic method for the determination of p-aminophenol in paracetamol powder is described. Second derivative absorbance (d²A/dλ²) values were measured at 223.8 nm (Δ = 4.2 nm) where p-aminophenol showed derivative responses obeying Beer's Law but paracetamol had negligible derivative absorption. The concentrations of p-aminophenol solutions prepared in 0.1 N HCl (0.12–7.61 mcg/ml), containing constant amounts of paracetamol (20 mcg/ml) related linearly with the d²A/dλ² values and gave a straight line (r = ?0.9999). The method allowed determination of 0.5% to 38% of p-aminophenol in paracetamol without prior separation, it is rapid, precise and accurate.     

Electrochemical Monitoring of Saos‐2 Cell Differentiation on Pyrolytic Carbon Electrodes

In this study we establish an electrochemical platform based on two dimensional (2D) pyrolytic carbon electrodes for in vitro analysis of osteoblast differentiation. Electrochemical impedance spectroscopy (EIS) was used to monitor cell adhesion and proliferation, while an electrochemical assay based on square wave voltammetry (SWV) was applied to measure the activity of the differentiation marker alkaline phosphatase (ALP). 2D pyrolytic carbon electrodes were fabricated and used to monitor Saos‐2 cell differentiation for a period of up to 21 days. With this method it was possible to detect a faster increase of ALP activity for cells cultured in medium supplemented with differentiation factors compared to cells cultured in growth medium. This was confirmed by the results obtained with Alizarin Red staining, showing that cells subjected to osteogenic medium went through the entire differentiation process, from proliferation to mineralization. Finally, for the first time, real‐time monitoring of ALP activity combined with continuous EIS monitoring of the same cell culture was achieved using the pyrolytic carbon electrodes.     

A new cloud-point preconcentration approach for the spectrophotometric determination of p-aminophenol in the presence of paracetamol with 2-(2-Hydroxyphenyl)-1H-benzimidazole as a coupling reagent

A preconcentration and determination method for trace p-aminophenol (PAP) in paracetamol was developed. Cloud-point extraction (CPE) was employed for the preconcentration of p-aminophenol prior to spectrophotometric determination using Triton X-100 (TX-100) as an extractant. The determination is based on the reaction of p-aminophenol with 2-(2-hydroxyphenyl)-1H-benzimidazole (HPBI) at room temperature in the presence of an oxidant to produce indophenol blue dye. The dye formed is subsequently entrapped in micelles of the surfactant TX-100. The surfactant-rich phase shows maximum absorbance at 650 nm and the proposed method is linear in the 0.1 to 5.0 mg mL⁻¹ concentration range. By preconcentrating 10 mL of the sample solution, a detection limit as low as 55 ng/mL was obtained after a single-step extraction and the experimental concentration factor achieved for this method was found to be 10. The stoichiometric composition of the dye is 1: 1 (PAP: HPBI). Some parameters such as HPBI, KIO₄, Na₂CO₃, and TX-100 concentration, extraction temperature, incubation, and centrifugation time, and the sample volume were investigated in detail. The established procedure was successfully adopted for the determination of p-aminophenol in the presence of paracetamol in various pharmaceutical preparations. The text was submitted by the authors in English.