2-（3,5-二氯-2-吡啶偶氮）-5-二乙氨基酚分光光度法测定啤酒中微量铬的研究

在0.09—0.16mol·L-1硫酸介质中,Cr2O72-与2-（3,5-二氯-2-吡啶偶氮）-5-二乙氨基酚作用,形成二离子缔合物,最大吸收波长533nm,表观摩尔吸光系数为为4.51×104L·mol-1·cm-1,铬含量在0—3.3μg·mL-1内符合比耳定律,用于啤酒样品中微量铬的测定,结果满意。     

Pt／活性炭催化剂催化硝基苯加氢制备对氨基酚

Ｐｔ／活性炭催化剂催化硝基苯加氢制备对氨基酚刘东志陈昌藻（天津大学应用化学系，天津３０００７２）关键词硝基苯，催化氢化，对氨基苯酚，复合催化剂，铂，钯，活性炭对氨基酚（ＰＡＰ）是一种重要的化工中间体，广泛应用于染料、橡胶及感光材料等工业，同时也是消炎...     

担载铂催化剂用于硝基苯催化加氢制对氨基苯酚的研究

研究了以活性炭、γＡ１２Ｏ３、γ－Ａ１２Ｏ３－ＴiＯ２为载体,用浸渍法制备的铂含 量为１％的担载铂催化剂,用于硝基苯催化加氢制对氨基苯酚。发现Ｐｔ／γ－Ａ１２Ｏ３－ＴiＯ２催化剂有较高的活性、选择性和较长的寿命,催化剂循环使用１０次后,对氨基酚的率仍高于８０％,优于常用的Ｐt／Ｃ催化剂 。测定了催剂的比表面积、孔结构以 及活性金属铂的分散度,发现孔结构与催化剂性能之间没有规律性的关系;而铂在γ－Ａ１２     

A Voltammetric Sensor Based on Modified Multiwall Carbon Nanotubes for Cysteamine Determination in the Presence of Tryptophan Using p‐Aminophenol as a Mediator

Determination of cysteamine and tryptophan is described by electrochemical methods using p‐aminophenol‐multiwall carbon nanotubes paste electrode. Cysteamine and tryptophan in mixture can each be measured independently from each other with a potential difference of 600 mV. The results showed that the electrocatalytic currents increased linearly with cysteamine and tryptophan concentrations over the ranges 0.5–300 µmol L^?1 and 10.0–650 µmol L^?1, respectively. The detection limits for cysteamine and tryptophan are found to be 0.14 and 5.9 µmol L^?1, respectively. The proposed method is successfully employed for the determination of cysteamine in both capsule and urine samples.     

Synthesis and characterization of two binuclear iron(III) complexes of aminoethanol derivatives of aminophenol as models for non-heme iron enzymes active sites

Two aminoethanol derivatives of aminophenol ligands were synthesized and characterized by IR and ¹H NMR spectroscopies. The binuclear iron(III) complexes of these ligands have been prepared and characterized by IR, ¹H NMR and UV-Vis spectroscopic techniques, cyclic voltammetry, single crystal X-ray diffraction and magnetic susceptibility studies. X-ray analysis revealed binuclear complexes, Fe₂(L₂), in which Fe(III) centers are surrounded by two phenolate and hydroxyl oxygen atoms, and amine nitrogens of the ligands. The metal active sites of both complexes are held together by the two above mentioned hydroxyl bridges. Variable temperature magnetic susceptibility indicates antiferromagnetic coupling between the iron centers of both complexes. This exchange coupling is stronger for Fe₂(L^ae)₂, such that it shows a room temperature strong coupling between the two iron centers. The investigated complexes undergo irreversible electrochemical oxidation and reduction.     

Cysteine and Methionine Derivatives of Aminophenol Ligands: Synthesis,Iron Complexation,Magnetic, Electronic and Redox Investigation

Two new Cysteine and Methionine derivatives of aminophenol ligands (HL^Cys and HL^Met) were synthesized by a convenient procedure. The ligands were characterized by ¹H NMR, ¹³C NMR and IR spectroscopies, ESI‐MS, elemental analysis and optical activity measurements. Iron(III) complexes (FeL^Cys and FeL^Met) of these ligands were synthesized and characterized by spectroscopic, magnetic susceptibility studies and cyclic voltammetry techniques. The molecular structure of FeL^Cys and FeL^Met determined by ESI‐MS consist of two ligands coordinated to Fe(III) centers. The magnetic susceptibility measurement indicates the monomeric complexes with paramagnetic properties. Both complexes undergo metal‐centred reduction, and ligand‐centred oxidation.     

岭回归分光光度法测定扑热息痛合成过程中多组分样品的研究

将岭回归分光光度法应用于扑热息痛合成过程中对乙酰氨基酚、对硝基酚、对氨基酚和醋酸４组分含量的分析研究。详细介绍了该法的基本原理和具体的分析步骤。实验结果表明,该法对样品中各组分的平均回收率在１００．１％～１０６．７％之间,相对标准偏差在２．０３％～５．２１％之间,结果较满意。与高效液相色谱法相比,两者测得结果的相对误差＜１５％。该法还具有简便、快速、适宜于计算机联机分析等特点。     

REMPI and IR-UV double resonance spectroscopy of 3-aminophenol·(NH3)1 cluster in the gas phase

The electronic and geometric structures of the cluster consisting of 3-aminophenol (3AP) and one ammonia molecule were investigated using resonance-enhanced multiphoton ionization and IR-UV double resonance spectroscopy in the gas phase. Between the cis and trans isomers found for the bare 3AP molecule, only trans isomer was found for 3AP·(NH₃)₁. It was found that complete quenching of the excited state of cis isomer, e.g. by conformer-specific excited state hydrogen transfer reaction, does not seem to occur, but that efficient conformational cooling drives the ground state population into the most stable trans isomer. The 0-0 band of the trans-3AP·(NH₃)₁ at 34 409 cm⁻¹ is red-shifted by 68 cm⁻¹ from that of the trans-3AP at 34 477 cm⁻¹. The IR depletion spectrum shows that the OH stretching vibration (3296 cm⁻¹) is red-shifted by 362 cm⁻¹ from that of the bare molecule. The large red-shift in OH frequency, combined with MP2 calculation, reveals that the structure of the cluster is the one with the nitrogen atom of ammonia bound to the hydroxyl hydrogen of aminophenol.     

An Electrochemical Assay for Monitoring Differentiation of the Osteoblastic Cell Line (MBA‐15) on the Sensor Chip

An electrochemical assay for the indication of the activity of the cell bound differentiation marker alkaline phosphatase (ALP) is proposed using voltammetry on an in‐vitro cell culture. The basis of the assay is cultivation of cells on gold microelectrodes in wells of a microplate, catalytic hydrolysis of p‐aminophenyl phosphate by ALP and indication of p‐aminophenol oxidation by square wave voltammetry (SWV) with the sensors onto which the cells attached. The morphology of the bone marrow stromal cell line (MBA‐15) on the electrode surface was investigated and it exhibited in vitro osteogenic characteristics. Since ALP is expressed on the cell surface in early differentiation stage of osteoblastic cells, its activity was followed after different culture times over a period of 144 h by recording repetitive voltammograms at different time points upon addition of the substrate p‐aminophenyl phosphate. The ALP activity was estimated from the signal increase related to formation rate of p‐aminophenol and the number of cells. The highest value was measured at 120 h, when the cells reached confluence. The results of the electrochemical activity assay are consistent with the colorimetric acquired value from p‐nitrophenol formation rate.     

MAP-H2O2-HRP伏安酶联免疫分析测定南方菜豆花叶病毒

提出间氨基酚(MAP)-H₂O₂-辣根过氧化物酶(HRP)伏安酶联免疫分析新体系,并用于南方菜豆花叶病毒(SBMV)的测定.以线性扫描二阶导数伏安法检测HRP催化H₂O₂氧化MAP的产物,用于游离HRP及SBMV的测定,灵敏度均高于经典的ELISA显色光度法.本法对HRP测定的线性范围为1.0×10^-8～1.0×10^-6g/L,检测限为3.8×10^-9g/L;对SBMV测定的线性范围为4.0～5000ng/mL,检测限为4.0ng/mL.用所建立的方法测定病毒感染病叶澄清液的最高稀释比为1∶1.5×10⁵,并与现行的ELISA显色光度法进行对照,二者相关性很好.