Soluble manganese(IV) as a chemiluminescence reagent for the determination of opiate alkaloids, indoles and analytes of forensic interest

We present the results of our investigations into the use of soluble manganese(IV) as a chemiluminescence reagent, which include a significantly faster method of preparation and a study on the effect of formaldehyde and orthophosphoric acid concentration on signal intensity. Chemiluminescence detection was applied to the determination of 16 analytes, including opiate alkaloids, indoles and analytes of forensic interest, using flow injection analysis methodology. The soluble manganese(IV) reagent was less selective than either acidic potassium permanganate or tris(2,2′-bipyridyl)ruthenium(III) and therefore provided a more universal chemiluminescence detection system for HPLC. A broad spectral distribution with a maximum at 730 ± 5 nm was observed for the reaction between the soluble manganese(IV) and a range of analytes, as well as the background emission from the reaction with the formaldehyde enhancer. This spectral distribution matches that reported for chemiluminescence reactions with acidic potassium permanganate, where a manganese(II) emitting species was elucidated. This provides further evidence that the emission evoked in reactions with soluble manganese(IV) also emanates from a manganese(II) species, and not bimolecular singlet oxygen as suggested by previous authors.     

ICP-AES法测定钢中酸溶铝和酸不溶铝及全铝

应用ICP－AES法测定了钢中酸溶铝和酸不溶铝，并对测定条件及相关参数进行了试验和优化，并于基体的干扰及方法的准确度和精密度也作了研究并标准物质作了验证。用此法所测得结果与标准物质的证书值间无显著差异，将酸不溶铝和酸溶铝的测得值相加即得总铝的量。     

Exchange of matter at the interface between two liquid phases

Theoretical models of the exchange of matter at interfaces are necessary to interpret relaxation phenomena in surfactant adsorption layers. For liquid-liquid systems, the diffusion-controlled exchanges of surfactant molecules at the interfaces can be influenced by a simultaneous transfer of molecules from one bulk phase to the other. The diffusional mass exchange function is derived taking into account the transfer across the interface. The resulting mass exchange function is used to calculate the interfacial tension response of a liquid-liquid system. As an example, the interfacial response after a ramp-type area perturbation is calculated.     

与聚合物发光器相关的若干问题的研究

结合作者在聚合物发光器相关的若干问题的研究结果，评述新型可溶性导电高聚物、透明导电离聚物薄膜，多孔硅与导电离聚物异质结的研究进展。     

Depolymerization of soluble silicate in dilute aqueous solutions

Experiments with diluted solutions of a customary water glas show that the rate of depolymerization depends not only upon pH and the SiO₂ concentration, but also varies systematically as a function of the type and concentration of an additional electrolyte. Increasing cation activities of metal chlorides are causing a decrease of the rate constant in the order 1) Na⁺, K⁺, 2) Mn²⁺, Mg²⁺, Ca²⁺, Sr²⁺, 3) Zn²⁺, Ni²⁺, Ce³⁺, Cu²⁺. With respect to anions of sodium salts the rate constants are increasing with increasing activities in the order NO ₃ ^– , HCO ₃ ^– , Cl^–, SO ₄ ^2– , whereas HPO ₄ ^2– causes a decrease. The results permit to identify those components of water which are most responsible for a change of the depolymerization rate and may be used to evalute the properties of a water glass as a possible anticorrosive agent for water supply systems.     

ROMP of t-butyl-substituted ferrocenophanes affords soluble conjugated polymers that contain ferrocene moieties in the backbone

A substituted ferrocenophane, 1,1′-((1-tert-butyl)-1,3-butadienylene)ferrocene, was synthesized and polymerized via ring-opening metathesis polymerization (ROMP) to give soluble high molecular weight polymers with ferrocenylene units in the backbone. The monomer readily underwent polymerization upon exposure to a tungsten-based metathesis initiator, W(CHC₆H₄-o-OMe)(NPh)[OCMe(CF₃)₂]₂ (THF), to give high molecular weight polymers (M_w=ca. 300,000). The molecular weights could be varied systematically by adjusting the monomer-to-catalyst ratio. UV/vis spectra revealed a bathochromic shift for the polymer, consistent with enhanced conjugation compared to the monomer. The polymer exhibited thermal properties similar to oligomeric poly(ferrocenylene). Cyclic voltammetry of the polymer suggested that the iron centers are coupled electronically. Upon doping with I₂ vapor, the polymers displayed semiconducting properties (σ=10⁻⁵ S cm⁻¹). Theoretical calculations were used to evaluate the nature of the bonding in these and related polymers.     

Remarks on the shear viscosity of surfaces stabilised with soluble surfactants

A survey is made of previously reported values of the surface shear viscosity of sodium dodecyl sulphate solution which reveals inconsistencies. The origin of these inconsistencies is thought to be due to the fact that, because SDS is a soluble surfactant, the surface deformation rate is governed by a three-dimensional sublayer adjacent to the surface and is therefore inherently experiment-dependent. Because of this, only an apparent surface shear viscosity that is specific to a particular experiment can be measured. However, for an insoluble surfactant, an intrinsic two-dimensional surface viscosity can be clearly defined. Some methods of measuring an apparent surface shear viscosity assume that the surface shear viscosity is the only surface property that determines the drainage rate from foam or individual Plateau borders but there is experimental evidence to show that other surface properties may be significant.     

Determination of isoniazid among pharmaceutical samples and the patients’ saliva samples by using potassium ferricyanide as spectroscopic probe reagent

A novel method to determine isoniazid with high sensitivity and good selectivity has been established by using potassium ferricyanide as spectroscopic probe reagent. In the presence of potassium ferricyanide, it has been demonstrated that iron(III) is reduced to iron(II) by isoniazid at pH 4.0. In addition, the in situ formed iron(II) reacts with potassium ferricyanide to give soluble prussian blue. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of isoniazid can be calculated based on this absorbance. A good linear relationship of the concentration of isoniazid versus absorbance is observed with a linear range of 0.040-8.00 μg mL⁻¹. The linear regression equation is A = −0.00286 + 0.28588C (μg mL⁻¹) with a correlation coefficient of 0.9992. The detection limit (3σ/k) is 0.037 μg mL⁻¹, and its relative standard deviation (R.S.D.) is 0.35% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of isoniazid is 3.92 × 10⁴ L mol⁻¹ cm⁻¹. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of isoniazid in pharmaceutical samples and saliva samples of patients.     

Comparison of calibrations for the determination of soluble solids content and pH of rice vinegars using visible and short-wave near infrared spectroscopy

Visible and short-wave near infrared (Vis/SWNIR) spectroscopy combined with chemometrics was investigated for the fast determination of soluble solids content (SSC) and pH values of rice vinegars. Two hundred and twenty-five samples (45 for each variety) were selected randomly for the calibration set, whereas, 75 samples (15 for each variety) for the validation set, and the remaining 25 samples for the independent set. After some preprocessing, partial least squares (PLS) analysis was implemented for calibration models with different wavelength bands including visible, SWNIR and Vis/SWNIR regions. The best PLS models were achieved with Vis/SWNIR (550–1000 nm) region. Furthermore, different latent variables (5, 6, 7, 8 LVs) were used as inputs of least squares-support vector machine (LS-SVM) to develop the LV-LS-SVM models with grid search technique and RBF kernel. The optimal models were obtained with 6 LVs and they outperformed PLS models. Moreover, effective wavelengths (EWs) were selected according to regression coefficients. The EW-LS-SVM models were developed and an excellent prediction precision was achieved, and the effectiveness of the EWs was also validated. The correlation coefficient (r), root mean square error of prediction (RMSEP) and bias for the best prediction by EW-LS-SVM were 0.999, 0.189 and 0.051 for SSC, whereas 0.999, 0.008 and −1.7 × 10⁻³ for pH, respectively. The overall results indicated that Vis/SWNIR spectroscopy combined with LS-SVM could be applied as a high precision and fast way for the determination of SSC and pH values of rice vinegars.     

新型可溶性含氟聚芳醚酮的合成、表征及性能

制备了新型可溶性含氟聚芳醚酮高性能材料, 使该材料结合了含氟聚合物与聚芳醚酮两种材料的优点, 既具有很好的热稳定性、溶解性和阻燃性, 又有较低的介电常数和吸湿性[5,9,10]. 对于提高聚芳醚酮类材料的性能, 拓展其使用范围和加工方法具有很大的开发前景和实用价值.