定量分析方法评价

对定量分析方法的评价，应该综合考虑精密度，准确度，灵敏度，线性范围，检出限，基体效应和耐变性等因素，一种具有推广价值的方法，应当简便，实用。     

分析方法的认证

一个方法在应用到分析实际试样之前，必须经过严格的认证，以确认分析方法在准确度、精密度、适用的浓度范围以及抗干扰能力等方面是否能够达到试样对分析方法的要求．另一方面，即使是可靠的方法，例如法定的分析方法，当一个实验室或个人初次使用时，也要通过认证，以证明在当时的条件下方法能被正确地执行．     

关于校正曲线建立和应用中一些问题的探讨

大多数仪器分析方法都是相对测量方法,需建立分析信号与分析物量值之间的相关关系,因此,正确建立和应用校正曲线是仪器分析中获得准确测定结果的基础。详细讨论了校正曲线的建立和标定方法,校正曲线的属性包括中心实验点的特性、校正曲线的精密度和置信区间、动态范围和线性范围的确定方法等。对校正曲线的应用中常遇到的一些实际问题如测定结果精密度的计算、标准偏差有效数字的确定、测定结果的表示方式等进行了讨论。     

原子吸收分光光度计计量检定中的几个问题

对原子吸收分光光度计计量检定中的几个问题作了一些探讨,并提出了相应的改进措施。     

气质联用仪结合吹扫捕集测定固体废物中挥发性卤代烃

使用岛津GCMS-QP2020 NX气相色谱质谱联用仪结合吹扫捕集CDS 7000E建立了固体废物中30种挥发性卤代烃的测定方法。样品置于棕色吹扫捕集瓶中,挥发性卤代烃经吹扫捕集富集后用GCMS进行分析,以SIM方式进行采集,内标法定量。30种挥发性卤代烃在1.0～20μg/L的浓度范围内相关系数R在0.995以上。2.0μg/L标准溶液连续进样,峰面积RSD为1.21%～8.05%。加标浓度为1.0μg/kg时,平行试验3次,各组分的回收率在69.07%～138.07%之间。该方法前处理简单、灵敏度高,完全满足固废中挥发性卤代烃检测的要求。     

定量分析课中几个问题的讨论

在普化与分析课中,常用以下可逆反应为例来讨论酸度对氧化还原反应方向的影响H_3AsO_4+2H↑++3I↑-=HAsO_2+I_3↑-+2H_2O 正向反应和逆向反应在定量分析中均得到应用:酸度高(4 mol.L↑-1HCl)时,As(V)氧化I↑-,析出的I_3↑-用Na_23_2O_3标液滴定,借此测定As(V);而在酸度低(pH8-9)时,则是I_3↑-氧化As(Ⅲ),借此测定As(Ⅲ).     

离子反应中几个问题的质疑

对离子反应的概念、离子反应的实质、离子方程式表示的意义及离子方程式的书写步骤产生质疑,指出这些问题并纠正。     

微波消解-电感耦合等离子体原子发射光谱法测定药用胶囊和明胶中铬

药用明胶为淡黄色或黄色颗粒,干燥、洁净、均匀,无夹杂物,其溶液没有不舒适气味,主要用于软硬胶囊、止血海绵和片剂糖衣的原材料。空心胶囊由药用明胶加辅料精制而成的帽、体两节胶囊壳组成,主要用于盛装固体药物[1]。《中华人民共和国药典》2010年版二部中增加了明胶空心药用胶囊和胶囊用原料明胶中铬的检测项目[2],规定试样用密闭微波消解、石墨炉原子吸收光谱法测定。该方法的灵敏度虽高,但测定用时较长。随着电感耦合等离     

分析化学中检出限和测定下限的探讨

分析化学中灵敏度是分析方法的主要参数,检出限为具体量度指标,特别是在痕量分析中,检出限的确定对于分析方法的选择具有重要意义。分析仪器在测定过程中存在着与噪音相区别的小信号检出问题,同时也存在分析方法能可靠测定物质最低含量的界限问题,这两个概念有着本质的不同。在实际应用中,仪器检出限、方法检出限及测定下限的概念经常混乱,笔者分类阐述了检出限及测定下限的含义和计算方法,以指导实际应用中的理解和计算。     

标准溶液制备中几个问题的探讨

标准溶液是化学实验室用于分析工作中的标准试剂,标准溶液浓度不准确会导致分析结果不可靠,无法对产品质量做出正确判断。标准滴定溶液是专用于滴定分析法的标准溶液,在制备标准滴定溶液过程中,每步操作正确与否直接影响到分析结果的准确性。     

土壤中易解析硫化物的解析条件研究

探索了在以磷酸为酸化剂条件下的实验条件,包括还原剂的添加、酸浓度选择的计算、系统的精密度、准确度的统计,目的是为土壤中硫化物的检出提供借鉴和参考。在以三种土壤为实验样本的实验中,对比磷酸、盐酸、硫酸为酸化剂的检出结果,添加20mL磷酸、1.5g乙二胺四乙酸二钠、0.25g抗坏血酸的检出结果和以硫酸为酸化剂的检出结果比较接近,同样酸度条件下添加抗氧化剂后的检出值和实际样品加标回收率都有提高。三种土壤的相对标准偏差分别是5.6%、6.1%、10.1%,样品加标回收率分别是77.8%、81.9%、64.4%。系统可以完成对部分金属硫化物、易溶硫化物完全解析,且不会因为氧化还原反应造成对S2-的正负误差。     

讨论式教学在仪器分析课程中的实践探索

In order to improve the quality of classroom teaching to better serve the purpose of cultivating talents, we explored the discussion teaching in instrumental analysis course based on its characteristics. In this paper, we summarized the teaching practice including introduction of course, teaching design, teaching process and teaching evaluation, which would provide experience for the exploration of classroom teaching in chemistry major.     

Use of Commercial Acrylonitrile Standard for Wastewater Analysis

Abstract

It was found that a commercially available aqueous standard solution of acrylonitrile (1 mg/ml) was below manufacturer specification in concentration when compared to an authentic standard prepared from the pure compound. Comparative analyses of the two solutions, commercial and laboratory prepared acrylonitrile, were conducted by gas chromatography using a flame ionization detector with analytical conditions similar to those recommended by the EPA for acrylonitrile analyses. The acrylonitrile content of the commercial solution was found to be approximately 30% lower than specified. Commercial venders have provided solutions of the 114 organic priority pollutants which are convenient for instrumental calibration. There needs to be concern for experimental results reported with regards to accuracy and estimated detection limit when using such standards.     

Practical method validation: Validation sufficient for an analysis method

Validation of an analysis method depends on the purpose of the method, the chosen technique and the procedure in question. Methods are used for different research, product development, process control and quality control purposes. The human and economical importance of results vary. Each of the techniques used, such as chromatography-(HPLC, HRGC, TLC), capillary electrophoresis-(CE), spectrophotometry-(UV/VIS, IR, fluorescence, AAS, ICP) or spectrometric techniques (NMR, MS) as well as the hyphenated methods, have their own special features and deficiencies which must be considered. The method can include a simple pretreatment or it may include many demanding steps, it can use automation and data processing in various ways, it can have an official status, it can be a thoroughly verified or less studied one. How should these differences be accounted for during the validation? What would be a sufficient certainty that the method does what is expected, that the method fits for the purpose it was intended? The client (or authority) decides the required timetable, cost and quality level. This is why within a laboratory different quality levels and associated levels of validation exist. This paper tries to outline a practical test frame for validation efforts to assist the analyst when planning validation of a method.     

不受电极斜率限制的离子电极标准加入法算图

格兰图在离子选择电极法中应用广泛,但该图要求电极响应的能斯特斜率为一定值。对电极斜率偏离理论值的情况进行修正已有报道。 本文提出一种不需任何电极斜率校正步骤的算图,即以加入标准溶液后电位的变化值△E与实际斜率S的比值△pe对加入标准溶液体积Vs作图的计算图(简称为△pe格兰图)。在实际操作中,根据测得的△E值和S值,经换算为△pe后,即可在标准算图上作图进行结果计算。克服了作空白溶液线或共线图线时可能引进的误差,简化了结果处理过程。此外,对不同价态离子的测定,该算图纵坐标标度△pe不变,不必扩大或缩小,作图十分方便。     

pH-Induced Difference Spectrophotometry in the Analysis of Binary Mixtures.

Abstract

A concise overview of selected literature concerning biosensors based on surface plasmon resonance and acoustic wave technologies is presented. A comparison in terms of their performance and potential advances in the bioanalytical field is discussed. This Mini-Review highlights the generally underrecognized potential of acoustic wave technology, in the field of biosensors relative to plasmon resonance, and focuses on stimulating not only the development of acoustic wave biosensors but also a broader and increased use of them. These sensors are anticipated to play a central role in biodetection in the near future.     

双波长标准加入法同时测定合金钢中钼和钨

在金属离子显色体系中,采用双波长分光光度法同时测定了合金钢中的钼和钨。对显色反应和光度测定的最佳条件进行了详细考察。在介质盐酸浓度为０．６～１．２ｍｏｌ／Ｌ,ＳＡＦ质量浓度为２０～６０ｍｇ／Ｌ,ＣＴＭＡＢ质量浓度为０．１８～０．４２ｇ／Ｌ的显色体系中,能够形成Ｗ－ＳＡＦ－ＣＴＭＡＢ和Ｍｏ－ＳＡＦ－ＣＴＭＡＢ络合物,吸光度值高且稳定。根据两络合物的吸收光谱,选择钼作为标准加入组分,在钨的等吸收点波长     

Self-assembled sensor based on boron-doped diamond and its application in voltammetric analysis of picloram

A self-assembled sensor based on a boron-doped diamond was investigated as a sensitive tool for voltammetric analysis of a member of a pyridine herbicide family - picloram. A cyclic voltammetry and a differential pulse voltammetry were applied for investigation of the voltammetric behaviour and quantification of this herbicide. Picloram yielded one well-developed irreversible oxidation signal at a very positive potential about +1.5 V vs. Ag/AgCl/3 mol L^?1 KCl electrode in an acidic medium and 1 mol L^?1 H₂SO₄ was chosen as a suitable supporting electrolyte. Operating parameters of differential pulse voltammetry were optimized and the proposed voltammetric method provided a high repeatability (a relative standard deviation of 20 repeated measurements at a concentration level of picloram of 50 µmol L^?1 equaled to 2.58%), a linear concentration range from 2.5 to 90.9 µmol L^?1 and a low limit of detection (LD = 1.64 µmol L^?1). Practical usefulness of the ‘environmentally-green’ electrochemical sensor was verified by an analysis of spiked water samples with satisfactory recoveries.