多元分辨校正模型与方法研究—无机多组份分析

系统研究了各种多元分辨校正模型、方法及其应用，以模拟体系、病态体系有态体系为对象，考察了它们的多元校正能力与多元分辨效果，给我机多组份分析态体系实例。     

Equivalence of the Pecka-Ponec Correlation Probability and the Statistical F Significance for MLR Models

In an article of this journal Pecka and Ponec [J. Math. Chem. 27 (2000) 13] have proposed, by means of a probability calculation, a method to evaluate the statistical importance of correlations obtained from multilinear regression equations involving an arbitrary number of experimental points and parameters. Here, it is demonstrated how this probability exactly coincides with a more general concept: the confidence probability of an F distribution having the appropriate degrees of freedom.     

t,F显著性检验应用中的一个问题

文章就ｔ，Ｆ显著性检验在同一个问题上检验判断的不一致性，提出在对一种分析结果（或测试结果）实施鉴定时，有必要同时进行ｔ，Ｆ的联合检验，而只有当联合检验一同被接受之后，所作用出的判定结论才是完整和可信赖的。     

不依赖于统计模型的手性毛细管电泳分离多指标同时优化

考虑到手性毛细管电泳分离机理的复杂性，提出了不依赖于统计模型的二进制编码遗传算法多目标优化策略。根据实验参数的多少及其重要性，采用均匀设计安排完成初步实验。并用Derringer功效函数作为多指标同时优化的评价指标，以取得较高的分离度和较快分离速度；通过对实验参数给予编码，转化为二进制字符串，根据得到的总功效函数值大小进行遗传算法操作，产生新的一组实验条件。重复上述过程直到得到最佳分离条件为止。此方法成功地应用于华法令对映体的毛细管电泳分离条件优化。     

High-throughput Screening: Establishing Mathematical and Physical Models for Bio-target Immobilization

In high-throughput screening, the immobilization of bio-target shows a significant effect on the target performance, especially the conformation. This, ultimately, has an influence on the screening quality. In present article, a series of mathematical and physical models for target immobilization were established. As shown, in the immobilization process, if the plot of C ^*/Q versus C ^* is a straight-line, the drugs obtained from in vitro screening are probably applicable to in vivo environment. Otherwise, when the linearity exists between ln Q or Q and ln C ^*, particularly between Q and ln C ^*, additional competition-experiments of known ligands are necessary. In addition, the immobilization in multilayer form, as well as its impact on screening quality, was also discussed in this article (C ^*, the equilibrium concentration of bio-target; Q, the adsorbance).     

直读光谱分析工作曲线中标样取值的认识

目前 ,在直读光谱分析中许多工厂自制了一些控样 ,用控样参与绘制工作曲线 ,校正待分析的试样。但也有不少单位由于种种原因 ,至今没有制作控样 ,或者控样并没有参与绘制工作曲线 ,这样 ,对工作曲线中标样取值的认识应该引起注意。最理想的光谱分析工作曲线 ,是参与绘制工作曲线的每一个点 ,即每一块标样有关的激发点 ,利用高斯 约登 (ＧａｓｓＪｏｒｄａｎ)权重最小二乘法 ,以光强比与其对应的浓度 ,用曲线关系式 :Ａ(ＩＲ) 3+Ｂ(ＩＲ) 2+Ｃ(ＩＲ) +Ｄ =%ｃｏｎｃ ,经过回归拟合之后 ,原标样的元素含量的定值与工作曲线上回归拟合的计算值…     

光谱预处理方法对混胺近红外定量模型影响的研究

本文探讨了一阶导数、Savitzky-Golay平滑、小波变换(WT)和正交信号校正(OSC)预处理方法对混胺组分近红外光谱的预处理效果。采用预测集标准偏差(SEP)对各种预处理方法的最佳参数进行选择。比较了各种预处理方法的去噪能力,对预处理方法组合后的效果进行了评价。研究表明,WT和OSC能有效去除噪声,提高分析模型的精度,WT和OSC结合后的预处理效果更好。     

On the Application of Surface Complexation Models to Ionic Adsorption

Surface complexation models (SCMs) have been used extensively to describe the acid-base properties and adsorption behaviors of inorganic and organic cations and anions on many single-phase adsorbents. The success of SCMs results from the conformation of adsorption to mass-action and material-balance laws and the flexibility in adjustable parameters. However, the assumptions made in the derivation of the SCMs are really not justified and the SCMs are not so thoroughly grounded in fundamental chemistry. The SCMs are really the data-fitting model, rather than the chemical model. The premises of application of SCMs are the accurate identification of surface species and the low surface coverage. Though the application of the SCMs comes into vogue, the SCMs should be applied with caution. Copyright 2000 Academic Press.     

Maintenance of Soft Calibration Models in the Determination of Zinc,Cadmium, Lead and Copper by Differential Pulse Anodic Stripping Voltammetry

A strategy for constructing a global multivariate calibration model that includes calibration samples measured over time on different days is developed and applied in electroanalysis. Both synthetic and real samples (tap, extracted and river water) are analyzed by differential‐pulse anodic stripping voltammetry, showing the suitability of the global model constructed that provides successful results similar to those of the usual multivariate calibration. In addition the capability of discrimination of this model is evaluated in prediction for the mean of three replicates with estimation of probability of false noncompliance, α, and false compliance, β, being found 3.1, 11.2, 6.7 and 64.7 nM for nominal concentrations of zinc, cadmium, lead and copper of 96.0, 40.4, 37.3 and 328.0 nM respectively when α=β=0.05. It has been proven that the use of the global calibration does not imply a loss of multivariate analytical sensitivity, using this parameter as quality index of the analytical procedure. The viability of using calibration maintenance strategies with electroanalytical techniques is shown, providing a way to save time and experimental effort when these techniques are used in routine analysis.     

On the Measurement of Phase Transition Temperatures in Physical Molecular Organogels

Methods of measurement of the phase transition temperatures in physical molecular gels are analyzed. The "falling ball" technique, NMR, and rheology are compared. Temperature versus concentration phase diagrams can be easily obtained, and the reliability and workability of the methods are discussed. It appears that rheology is the more accurate and convenient technique while the falling ball method provides acceptable DeltaH, DeltaS values, but the melting temperature values are significantly altered. With NMR, kinetic information associated with the molecular aggregation process can also be extracted. Copyright 2000 Academic Press.     

On the Use of Monolithic Sol–Gel Derived Mesoporous Silica for the Calibration of Thermoporisemetry Using Various Solvents

Sol–gel derived mesoporous monolithic silica gels have been prepared to be used as standard materials for thermoporosimetry. The technique has been calibrated with n-heptane and cyclohexane and R _p = f(Δt) and W _a = f(ΔT) expressions are derived. In the specific case of cyclohexane, the solid to solid phase transition has been used. It is also shown that porous volumes can be measured by thermoporosimetry and that the correlation with N₂ gas sorption results is very good. Finally, thermoporosimetry has been applied to the study of cross linking level in polyisoprene samples containing a gradient of cross linking agent.     

Calibration of Circular Dichrometers

Abstract

The tris (hydroxymethyl)aminomethane salt of d-10-camphorsulfonic acid (TRIS-CSA) provides a convenient, non-hygroscopic alternative to the parent compound in the calibration of circular dichrometers. The molecular ellipticities, [6], of TRIS-CSA at 291 and 191 nm are 8015± 11 and -16, 130± 40 deg cm² dmol^?1, respectively. The circular dichroism (CD) maxima in terms of δε are 2.429 1 cm^?1 mol^?1 at 291 nm and -4.888 1 cm^?1 mol^?1at 191 nm. TRIS-CSA has an ORD peak at 306.5 nm, a zero crossover at 292 nm, and a trough at 270.5 nm (molecular rotation, [M]_306.5=4475± 10, [M]_270.5= -5615± 10 deg cm² dmol^?1), and a molar absorptivity, ε, of 35.9± 0.2 1 cm^?1 mol^?1 at 286 nm.     

Application of Statistical Lattice Models to the Analysis of Oscillatory and Autowave Processes in the Reaction of Carbon Monoxide Oxidation over Platinum and Palladium Surfaces

Statistical lattice models which imitate oscillatory and wave dynamics in the adsorbed layer during of carbon monoxide oxidation over Pt(100) and Pd(110) single crystals differing in the mechanism of autooscillation formation are compared. In the case of platinum, oscillations are due to phase transitions of the catalyst surface structure and surface reconstruction under the action of the reaction medium. In the case of palladium, the driving force of oscillations is phase transitions in the adsorbed layers on the catalyst surface, namely, the reversible formation of subsurface oxygen in the course of the reaction, which modifies the adsorption and catalytic properties of the surface. It is shown that, according to the proposed models, a change in the coverages (CO_ads O_ads) in the autooscillation regimes occurs via the formation of a surface wave whose front is characterized by the high concentration of catalytically active sites that provide the maximal rate of CO₂ molecule formation. Under certain conditions, the formation of various spatiotemporal structures is observed in simulation experiments.     

Calibration of titration methods

Summary A calibration method is proposed which makes it possible to use titration techniques in the presence of systematic errors, even if these errors depend on the concentrations of the analytes. The approach uses an empirical calibration model which approximates the relationship between apparent (found) and true concentrations of the analytes. Also a calibration of the physical model of the titration process is proposed, as well as a method of determination of the model parameters, which are useful when analytes are determined by fitting the model to experimental data of titration. Both approaches, empirical and based on the physical model, may be applied jointly. The example presented reveals high efficiency of the proposed approach in cases when a deficient physicochemical model of the titration process is used in the determination of an analyte concentration (simulated titration data applied). The calibration proposed may be considered as a generalization of the titrant standardization used in the conventional volumetric analysis. It may be applied to all titration techniques and for all methods of end-point detection and determination of the concentration of analytes. It opens new possibilities for the development of titration methods. Permanent address: Department of Analytical Chemistry, Jagiellonian University, Karasia 3, PL-30-060 Krakow, Poland     

Calibration of Circular Dichrometers in the Visible Region

Abstract

The cesium salt of R, R-(-)-trans-l, 2-cyclohexane-diaminetetraacetatocobaltate(III), Δ-(+)₅₄₆-Cs[Co(R, R(-)-CDTA)], Δ-Cs[Co(R, R(-)CDTA)]), provides a compound which can be used for calibration of circular dichrometers in the visible region. Δ-Cs[Co(R, R(-)CDTA)] has three major circular dichroism (CD) maxima at 593 nm, 527 nm, and 240 nm. The molecular ellipticities, [θ], at 593 nm, 527 nm, and 240 nm are -4490 ± 40, 5720 ± 40, and -47, 900 ± 300 deg cm² dmol^?1, respectively. The CD maxima in terms of Δε at 593, 527, and 240 nm are -1.36 ± 0.01, 1.73 ± 0.01, and -14.5 ± 0.1 l cm^?1 mol^?1, respectively. Optical rotatory dispersion (ORD) and ultraviolet-visible absorption data has also been obtained for this compound.     

Statistical properties of the band-broadening function

Statistical properties of the band-broadening function calculated from the equilibrium and kinetic theories of Giddings and Eyring are compared with real liquid-chromatography elution curves of low-molecular-weight substances and with light-scattering elution curves of a high-molecular-weight polystyrene standard injected at several concentrations. The curves obtained by liquid chromatography agree in a large span of elution times with the theoretical ones and can be described by one value of the plate-height. The size exclusion chromatography (SEC) elution curves seem to approach the predicted statistical properties with decreasing concentration of injected polymer but, in general, a reliable prediction of band-broadening (BB) functions in SEC of polymers, especially of non-symmetric BB functions near the exclusion limit, seems not possible at this point. The relation of the theory with the characteristic-function approach developed by Dondi is also discussed.     

Statistical interpretation of the Dubinin-Radushkevich equation

A statistical approach was applied to describe the model of a homogeneous microporous adsorbent and obtain the dependences of the thermodynamic functions on the number of molecules and the temperature for molecular aggregates in discrete micropores over a wide region of fillings that lead to the Dubinin—Radushkevich equation. The energy nonuniformity of the adsorption space is the fundamental property of carbon adsorbents. In the region of small fillings, the statistical approach leads to Henry's law and the finite value of the initial differential energy of adsorption. The value of sorption corresponding to the saturated vapor pressure decreases with increasing temperature, but the decrease is considerably less than for the density of the corresponding liquid. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 261–265, February, 1999.