Complications in the Use of the Taylor Dispersion Method for Ternary Diffusion Measurements: Methanol + Acetone + Water Mixtures

The Taylor dispersion technique is used to measure the ternary mutual diffusion coefficients of aqueous nonelectrolyte solutions at 25°C. The dispersion of the injected solutes is recorded by a differential refractometer and an ultraviolet-visible detector. The diffusion coefficients are calculated directly by fitting the theoretical dispersion equations to about six experimental curves simultaneously. If the ternary diffusion effects in the measured dispersion profiles are not confused by the inaccuracy of the experimental method or an unfavorable relative detector sensitivity, the diffusion coefficients are precise. For the system methanol + acetone + water, it is shown that the Taylor dispersion method is unsuitable for the determination of all the diffusion coefficients if the methanol mole fraction is less than 0.45 or the acetone mole fraction if more than 0.001.     

Investigation of the Structures of the Product Ions Produced via self-CI of Acetone

TheacetoneselfCImassspectrumAcetoneselfCImassspectrumisgiveninTable1.Table1.MajorproductionsandtheirrelativeabundanceofacetoneselfCIMSTheformationofionatmlZ73AnotherproductionintheselfCIMSofacetoneistheionatm/z73.InselfCIMSofacetone-d6,thecounterpartistheionatInjz82.InselfCIMSofthemixtureofacetoneandacetone-d6inaratioofl:l,thecorrespondingionsaretheionsatInlz73,76,79and82.TheirCIDreactionresultsarelistedinTable2.Table2.TheCIDMSoftheionatIn/z73andanalogsOnthebasisofthedatainTab…     

Spectroscopic properties in the liquid phase: combining high-level ab initio calculations and classical molecular dynamics.

We present an integrated computational tool, rooted in density functional theory, the polarizable continuum model, and classical molecular dynamics employing spherical boundary conditions, to study the spectroscopic observables of molecules in solution. As a test case, a modified OPLS-AA force field has been developed and used to compute the UV and NMR spectra of acetone in aqueous solution. The results show that provided the classical force fields are carefully reparameterized and validated, the proposed approach is robust and effective, and can also be used by nonspecialists to provide a general and powerful complement to experimental techniques.     

球状多孔Pd纳米粒子超结构的合成及其对甲酸的电催化氧化

在丙酮／水混合溶剂中,以氯代十六烷基吡啶为结构导向剂,水合肼还原PdCl42-,制得了直径范围在30～50nm之间的球状多孔Pd纳米粒子超结构．实验表明,氯代十六烷基吡啶对球状多孔Pd纳米粒子超结构的形成起着重要的作用,不加该表面活性剂时,得到的是实心Pd纳米粒子;而丙酮主要影响表面活性剂胶束的尺寸．此外,本文还研究了球状多孔Pd纳米粒子超结构对甲酸氧化的电催化活性,在0．5mol／L H2SO4＋0．5mol／L HCOOH溶液中的循环伏安结果表明,球状多孔Pd纳米粒子超结构修饰电极在酸性溶液中电催化氧化甲酸的峰电流约为180mA／mg,明显优于实心Pd纳米粒子修饰电极（峰电流为120mA／mg）,且表现出较高的稳定性．     

丙酮肟氧化偶联合成2,3-二甲基-2,3-二硝基丁烷反应的研究

以丙酮肟为原料,在改性TS-1(钛硅分子筛)催化剂催化下,可用H2O2氧化偶联合成2,3-二甲基-2,3-二硝基丁烷(DMNB).在此基础上以丙酮为原料,在改性TS-1催化剂催化下,一锅法进行丙酮氨肟化和氧化偶联反应可制备收率43.2%的DMNB.该方法简便易操作,操作安全.产物结构经1H NMR,13C NMR表征.     

在丙酮增敏作用下硝普钠分光光度法测定盐酸吗啉胍

摘要：建立了可见分光光度法测定盐酸吗啉胍的新方法。研究表明,当NaOH浓度为0.13mol/L,在丙酮存在下硝普钠与盐酸吗啉胍反应生成紫色N-亚硝基类化合物,其最大吸收波长为508nm,表观摩尔吸光系数2.5×10³ L/（mol•cm）。盐酸吗啉胍浓度在0.38×10^-6~3.0×10^-4 g/mL范围内与吸光度呈现良好线性关系,线性回归方程A = 0.02292 + 0.01213c (10^-6 g/mL),线性相关系数r=0.9998,检测限(3σ/k)为0.25×10^-6 g/mL,RSD = 0.21%。本方法可用于药物样品和血清中盐酸吗啉胍含量的测定。     

Electrogravimetric Analysis by Quartz-Crystal Microbalance on the Consumption of the Neurotransmitter Acetylcholine by Acetylcholinesterase

Electrogravimetric analysis was performed on the consumption of the neurotransmitter Acetylcholine (ACh) by Acetylcholinesterase (AChE) in situ and in real time. Michaelis-Menten assumption was achieved by using an enzyme micro-reactor in which the total enzyme was anchored in a quartz crystal microbalance chip (QCM-chip) with a strategically engineered self-assembled monolayer (SAM) of alkanethiols, which can prevent diffusion-controlled or spatially restricted kinetics. The real-time frequency changes indicated the rate of the products formation from enzymatic reaction. The QCM-chip was tested showing that it could demonstrate AChE inhibition by physostigmine.     

Reaction of aryldiazonium salts with acetone oxime

The reaction of aryl diazonium salts containing electron-withdrawing substituents in the aromatic ring with acetone oxime leads to the formation of nitrogen-containing products instead of the expected functional derivatives of 1-alkyl-3-aryltriazene 1-oxides. The structure of these products is a function of the number and chemical nature of the substituents in the diazo component.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1911–1913, August, 1992.     

Rapid HPLC method for acetyl starch determination in blood

Summary Colloidal plasma substitutes of chemically modified starch are used in surgery and in emergency medicine. Acetyl starch (ACS) is a new plasma substitute based on an amylopectin acetic ester. Metabolic cleavage of the ACS ester substituents leads to improved degradation and elimination of infused polymer. To determine the metabolic fate of ACS a rapid LC-method for ACS quantitiation in blood samples was needed. For this purpose a size-exclusion chromatography (SEC) system with improved sensitivity is outlined using a refractive index detector. The limit of detection is 0.005 mg mL⁻¹. From 0.10–5.00 mg mL⁻¹ a linear relationship (correlation coefficient R=0,9999) between the RI signal and ACS concentration is obtained. Recoveries of ACS from blood plasma range 102.3–107.7% for ACS 200/0.5 (range 0.20–7.94 mg mL⁻¹) and 103.0–111.4% for ACS 200/0.7 (range 0.19–9.33 mg mL⁻¹). Only small differences between runs are obtained. In the inter assay test coeficients of variation of 1.8% and of 2.6% respectively are obtained for ACS 200/0.5 and ACS 200/0.7.