聚合氯化铁中OH／Fe物质的量比的测定

讨论了测定聚合氯化铁中OH/Fe物质的量比的几种方法,确定用过量碱沉淀法测定聚合氯化铁中的OH/Fe物质量比;同时研究了影响测定的各种因素,找出了最佳的测定条件.通过对合成试样和未知试样的测定,结果表明方法无系统误差存在,结果准确、可靠.     

微量含有物的分析方法

本发明提供迅速地分析材料中的微量含有物的方法，该方法在制备用于分析材料中的微量含有物的试样时，不进行长时间的提取处理，而是通过1次短时间的提取处理来进行。本发明的微量含有物的分析方法包括以下的工序：在试样台上载置被分析材料的试样片的工序、在试样台上滴加从试样片提取含有物的溶剂，在试样台和载置在试样台上的试样片的间隙中注入溶剂的工序、在室温保持注入在试样台和试样片的间隙中的溶剂，利用保持在试样台和试样片的间隙中的溶剂从试样片提取含有物的工序、以及分析从试样片提取的含有物的工序。     

兴奋剂检测中的化学衍生化方法

本文评述了兴奋剂检测中的各种化学衍生化方法,对蛋白同化激素、麻醉镇痛剂、β-阻断剂和利尿剂分别进行了讨论。这四类药物结构各不相同,但绝大多数属于高沸点、难挥发的极性化合物,不适于直接进行GC或GC/MS分析。通过化学衍生化.不仅可增大试样的挥发性和稳定性,减小样品的极性,使原来难以进行GC分析的试样转变成适合于色谱分析的试样,而且通过衍生化还可达到改善分离效果、提高检测灵敏度的目的。     

示差折光和光散射双检测体积排除色谱的绝对定量化

讨论了示差折光和光散射联用双检测体积排除色谱的绝对定量化的原理,强调指出了试样注入量在数据处理中的重要作用.测量注入试样的这两种检测器的检测常数,可以同时得到试样的折光指数增量和重均分子量的绝对值.这一方法除了适用于各种均聚物外,还可以应用于高分子混合物的分析.此时,如将混合物看作为单一溶质,从所得折光指数增量和重均分子量,可对它们的组成作出定量分析,还可以判断共混物两个组分之间有无分子缔合等现象的产生.这一方法应用于聚甲基丙烯酸甲酯/聚苯乙烯(PMMA/PS)混合物的溶液,指明在四氢呋喃中两者产生缔合而形成了复合物.     

用于研究ICP-MS中基体效应的逐级稀释法

用逐级稀释法研究了ICP-MS测定痕量稀土时的基体效应,并将该法对高纯稀土、土壤和生物等样品的实验结果与常用的加入基体法的结果进行了比较.结果表明,两种方法所得出的基体最大允许浓度值相近.与常规的基体效应研究方法相比,逐级稀释法操作简便、易行,无须使用任何高纯物质作基体,且适用于任何化学组成复杂的试样体系,在实际分析中具有应用价值.为了验证该方法的可靠性,对含不同基体的标准试样中的痕量稀土进行了测定,所得实验数据表明,测定值与参考值一致.     

测氢扩散系数的电化学交流法研究

应用电化学交流法测定氢在纯铁中的扩散系数 .证明对电解氢在试样中的非稳态扩散 ,按菲克第二定律所设定的边界条件符合实际扩散行为 ,并论证了该方法的可行性     

iPP/HDPE/CB复合材料的制备及反常的温度-电阻效应

本文利用普通熔融挤出法制备了iPP/HDPE/CB复合材料, 分别采用注射成型及压制成型方法得到测试试样. 通过研究复合材料体积电阻率随温度的变化, 考察注塑试样和压制试样的PTC特性及复合材料形态结构与试样PTC特性之间的关系.     

盐酸-过氧化氢封管分解法在贵金属及其合金与金属锆分析中的应用

在化学分析中的某些情况下,一个溶样方法的选择,决定了测定的成败(如铱合金分析)。为了分析试样、试剂合成或制备标准溶液而常采用的热压分解法(其中包括玻璃封管法及压力溶样器法)是贵金属分析中分解试样的重要方法之一。已有文献介绍,方法是将试样与溶剂一起密封后,在加热的条件下,溶剂蒸气压增大,从而大大提高了试样分解的效率,加快了分解速度又节省了溶剂。是分解贵金属、稀有金属、合金、矿物及有机物等试样的有效方法。     

热历史对已固化环氧树脂松弛行为的影响

<正> 环氧树脂是一种性能优良且应用广泛的高分子材料,近年来,人们对已固化环氧试样在玻璃化温度(T_g)以下贮存时,物理性能随时间而变化的物理老化现象进行了广泛的研究.Ophir等发现已固化环氧试样经淬火处理后,其T_g随贮存时间升高,认为是由于自由体积随贮存时间减小所致.Mijovic用不同的方法进行过类似的研究,发现淬火环氧试样的T_g随贮存时间降低,认为是由于试样中的内应力松弛所致.本文试图进一步搞     

钙掺杂对La2-xCaxCe2O7-δ性能影响研究

利用高温固相反应法制备了高温质子导体La2-xCaxCe2O7-δ(0≤x≤0.2)。分别利用X射线衍射(XRD)、扫描电子显微镜(SEM)对试样的相组成、微观形貌进行了表征。并对试样在水蒸气和CO2气氛中的化学稳定性进行了测试。研究了不同掺杂量和不同测试气氛对La2-xCaxCe2O7-δ电性能的影响。实验结果表明:1 500℃烧结的试样均形成萤石型结构;试样在CO2和水蒸气气氛中表现出良好的化学稳定性。试样在湿润氢气气氛下的电导率明显高于干燥空气气氛,x=0.1的试样在湿润氢气气氛中具有最高的电导率,850℃时达到3.16×10-2S.cm-1,电导活化能为84.93 kJ.mol-1。     

Solving matrix effect,spectral overlapping and nonlinearity by generalized standard addition method coupled with radial basis functions–partial least squares: simultaneous determination of atorvastatin and amlodipine in urine

For simultaneous determination in conditions with spectral overlap and variation of matrix effects, coupling of the generalized standard addition method (GSAM) with the multivariate nonlinear method of radial basis function–partial least squares (RBF–PLS) was proposed. The nonlinearity caused by the GSAM used to correct matrix effects was studied, and principal component analysis was proposed for identifying it. In the method introduced, the whole sensor range can be used without the collinearity problem encountered in the application of GSAM with classical least squares (CLS), and calibration can be made for each analyte, separately. The introduced method was applied to determine amlodipine and atorvastatin in urine samples. The mean of the percent recoveries was between 95 and 101.12. The percent relative standard deviation values of the method were in most cases below 5%. The results of GSAM–RBF–PLS were compared with those obtained by GSAM–CLS and GSAM–PLS. Copyright © 2013 John Wiley & Sons, Ltd.     

Application of generalized standard additions method to inductively coupled plasma atomic emission spectroscopy with an echelle spectrometer and segmented-array charge-coupled detectors

Simultaneous correction for both spectral interferences and matrix effects in inductively coupled plasma atomic emission spectrometry can be accomplished by using the generalized standard additions method (GSAM). Results obtained with the application of the GSAM to the Perkin-Elmer Optima 3000 ICP atomic emission spectrometer are presented. The echelle-based polychromator with segmented-array charge-coupled device detectors enables the direct, visual examination of the overlapping lines Cd(I) 228.802 nm and As(I)228.812 nm. The slit translation capability allows a large number of data points to be sampled; therefore, the advantage of noise averaging is gained. Pure spectra of each of the spectrally active components in the sample can be extracted through the GSAM calculation.     

Evaluation of volume and matrix effects for the generalized standard addition method

A volume-dependent problem in use of the generalized standard addition method (GSAM) is evaluated. It is shown both mathematically and experimentally how to correct the deficiency. The revised GSAM was applied with direct current plasma spectroscopy in the presence of a salt and an acetone matrix effect.     

Test of the generalized standard addition method and linearization algorithms for the direct,simultaneous, multi-element analysis of solid samples by electrothermal atomic absorption spectrometry

The application of a multi-element electrothermal atomic absorption spectrometry (ETAAS) instrument with line sources and Zeeman-effect background correction to the direct, simultaneous determination of Ag, Cd, Cr and Pb in solid reference materials is described. Due to the occurrence of interference effects, the generalized standard addition method (GSAM) was required for calibration purposes. In order to extend the dynamic range for analytes present at high concentrations, linearization algorithms were tested. The combination of the GSAM and extension of the linear range, when necessary, generally yielded acceptable analytical results for the suite of elements studied, and may provide a useful approach to calibration in the direct analysis of solid samples by multi-element ETAAS. However, while linearization yielded good results for Ag and Cd in solid reference materials, it remains to be demonstrated that acceptable performance can be obtained for other elements in real samples.     

The fluorescence enhancement effect of the Tb-Gd-guanosine-5′-triphosphate-phen system and its analytical application

The simplified generalized standard additions method (GSAM) was investigated as an alternative method for the ICP-OES analysis of solid materials, introduced into the plasma in the form of slurries. The method is an expansion of the conventional standard additions method. It is based on the principle of varying both the sample mass and the amount of standard solution added. The relationship between the sample mass, standard solution added and signal intensity is assumed to be linear. Concentration of the analyte can be found either geometrically from the slope of the two-dimensional response plane in a three-dimensional space or mathematically from the ratio of the parameters estimated by multiple linear regression. The analysis of a series of certified reference materials (CRMs) (cement CRM-BCS No 353, gypsum CRM-Gyp A and basic slag CRM No 382/I) introduced into the plasma in the form of slurry is described. The slurries contained glycerol and hydrochloric acid and were placed in an ultrasonic bath to ensure good dispersion. Table curve 3D software was used to fit the data. Results obtained showed that the method could be successfully applied to the analysis of cement, gypsum and slag samples, without the need to dissolve them. In this way, we could avoid the use of hazardous chemicals (concentrated acids), incomplete dissolution and loss of some volatiles. The application of the simplified GSAM for the analysis did not require a CRM with similar chemical and mineralogical properties for the calibration of the instrument.     

Genetic algorithm-based method for selecting conditions in multivariate determination of povidone-iodine using hand scanner

Application of hand scanner in multivariate quantification of povidone-iodine (PVI), as a popular antiseptic agent, in some of pharmaceutical products is presented. Brightness, contrast, and mixed gamma were the adjustable scanner parameters. For selection of optimum values of the scanner parameters, partial least squares (PLS) and multiple linear regression (MLR), coupled with genetic algorithm, were performed. For the selected variables, both MLR and PLS performances were similar and appropriate. From the results obtained, it was concluded that the simpler method of MLR could be successfully applied instead of PLS, which requires more statistical experience. The considered concentration range for PVI in the calibration and prediction samples was 0.0-10.0% (w/v). For the analysis of pharmaceutical samples, generalized standard addition method (GSAM) was applied (on the variables selected by GA) and desirable results were obtained. Relative standard error (RSE) of less than 8% was obtained for the majority of samples analyzed.     

Flow injection calibration methods for atomic absorption spectrometry

The use of an atomic absorption spectrometer as a detector in flow injection analysis is briefly reviewed. A new simplified model is described for the dispersion effects observed with such systems; the model is based on considering the dispersion to be due to a single hypothetical mixing chamber located immediately prior to the measurement stage. The utility of this approach is demonstrated for two methods of calibration commonly used in atomic absorption spectrometry, and it is shown that flow injection sample and standard handling techniques are comparable to manipulation with volumetric apparatus. The flow injection method has a number of advantages for the analogue of the standard addition method. The use of an exponential concentration gradient is proposed as a novel method of calibration using a single concentrated standard. Results are presented for the determination of chromium in standard steels.     

原子荧光光谱法测定蛇粉中汞的方法研究

用微波消解仪消解、氢化物发生-原子荧光光谱法测定蛇粉中的微量Hg,优化了仪器的工作条件。测定汞的检出限为0.7pg/mL。测定0.3及1ng/L Hg标准溶液,相对标准偏差分别为4.1%及0.9%,加标回收率为87%~110%。     

flow injection systems wiht inductively-coupled argon plasma atomic emission spectrometry: Part 2. The generalized standard addition method

In multicomponent analysis by inductively-coupled argon plasma emission spectrometry, the generalized standard addition method is useful in overcoming matrix and/or spectral interferences. As this method requires many standard additions, it becomes cumbersome when done manually if many elements are to be determined. By using a flow injection system, the standard addtion manipulations required can be significantly simplified and completed within a shorter period of time with much less sample material. A flow injection system with merging zones is used to demonstrate the method for analyses of a Ni/Cu/Zn standard and of alloys. The reproducibility of measurements of the injected sample, with or without additions of standards is always better than 99%. The results obtained compare well with those obtained by the manual procedure and also with those obtained by atomic absorption spectrometry.     

Internal standard in flow injection analysis with amperometric detection

In this work, we describe for the first time the use of the internal standard method in flow injection analysis (FIA) with amperometric detection. The method is based on the application of sequential potential pulses to the working electrode in an electrochemical flow cell. The sequence of potential pulses is selected in such a way that the analyte and internal standard compound are detected and monitored individually and independently at the same working electrode. This approach compensates for random errors associated with variations of flow rate, injection volume, ionic strength difference between standards and samples, and accidental insertion or formation of air bubbles in the carrier stream. In addition, this method can overcome the major drawback of amperometric detection using solid electrodes, which is gradual electrode passivation. To illustrate the potential of this method, the flow-injection amperometric detection of uric acid using [Fe(CN)₆]^3? as an internal standard (IS) is presented as an example.