流动注射分析

本文是《分析试验室》定期评述专号中“流动注射分析”课题的第二篇评述文章。它评述了1988年10月至1990年10月流动注射分析在我国的进展及国际上发展的新动向。内容包括:基础研究、实验装置与仪器、分光光度分析、原子光谱、电化学检测和化学发光分析、梯度技术与计算机方法等。     

可更新表面分析技术进展

概述了流动注射及顺序注射可更新表面分析技术及仪器的进展。介绍了该技术原理、仪器系统、流通池等方面的新发展以及在传感器、免疫分析、生物配位作用检测、酶反应检测、细胞功能检测等领域的应用。参考文献32篇。     

一种共聚焦激光诱导荧光检测器的研制

 基于共聚焦检测，研制了一台便携式激光诱导荧光检测器。该系统具有体积小、重量轻、成本低等特点；成像观察校准系统使日常校准非常简单。采用毛细管电泳和流动注射方式对该体系性能进行了评价，以Cy5染料与Cy5标记的色氨酸作为检测物质，其检测下限为3.7 nmol/L。     

常见鼠药中毒及检测技术研究进展

鼠药是控制有害啮齿类动物最经济有效的方式,而大多数鼠药对人畜均具有较强的毒性。鼠药的不合理使用严重威胁人类和其他非靶标动物的生命安全。由误食、二次中毒、自杀及恶意投毒等原因导致的中毒事件时有发生。发展快速准确的鼠药中毒检测技术对于及时确定中毒靶标从而进行有效干预、对症治疗是降低鼠药危害的重要手段。常规的鼠药检测大多基于液相色谱-串联质谱等仪器分析方法。近年来,免疫分析技术由于具有操作简单、快速的优点,开始用于鼠药的快速检测。该文重点针对典型的氟乙酰胺、毒鼠强和抗凝血类鼠药的中毒概况和检测技术进行了总结,以期为相关领域研究人员提供技术指导。     

发挥技术优势 加大大型仪器的技改力度

湖北省地质实验研究所是一所以地质实验和化学分析测试,岩矿鉴定,选冶试验为主的专业地质实验研究单位,进入９０年代以来又在原技术优势的基础上发展了建筑检测,非金属矿产品开发,黄金珠宝检测,智能化仪器研制等延伸专业。近年来获得了良好的社会效益和经济效益。我所之所以能充分发挥技术优势,保持在激烈的市场竞争中立于不败之地,主要经验之一就是针对我所技术装备的状况,有效地加大技术改造的力度,有计划地解决了大型仪器的技术改造问题。我所拥有各类仪器设备３００多台（套）,总原值７４９万元。其中大型精密仪器１２台（套…     

氟离子仪器分析方法研究进展

近几年社会公众对氟离子的关注度显著提高,氟离子含量的检测技术也在不断更新和发展。该文介绍了氟离子含量测定的各类仪器分析技术及其优缺点,主要包括氟离子选择电极法、离子色谱法、反相-高效液相色谱法以及气相色谱法。     

流动注射—在线分离富集与原子光谱检测联用技术

现代分析化学发展的重要特征之一是分析方法从离线/手动操作向在线/自动操作方向转化。流动注射(FI)作为非均匀和非平衡状态下的溶液处理和微量进样技术,是实现上述转化的有力工具。FI可与不同的分离富集和检测手段结合,具有很强适应性和实用性。在众多联用技术中,FI—在线分离富集与原子光谱检测联用技术特别受到分析化学界的青睐。这种联用不仅可以克服常规离线操作费时、污染环境和试样/试剂消耗大的缺点,而且可大大提高分析效率,显著改善分析方法的灵敏度与选择性,进行多种成分同时检测(对ICP—AES,DCP—AES     

新一代CCD光谱仪的性能和特点

80年代初 ,英国阿朗技术公司致力于将 CCD技术应用于光谱仪的制造中。目前这种结构小巧但技术含量很高的仪器 ,已成为当今世界上性能价格比最好的光电直读光谱仪。阿朗公司作为 CCD技术的先驱 ,其产品以优良的性能和卓越的品质在同行业中占据先导地位 ,并行销全球。CCD光谱仪有许多优点 ,在技术性能上不仅完全满足了工业用户的需求 ,并与大型光谱仪相比 ,在运行成本、稳定性、灵活性等具有明显的优势。阿朗公司生产的 METALSCAN2 50 0 /2 0 0 0型台式金属光谱分析仪 ,适用于金属冶炼、铸造及加工行业实验室和炉前快速定量分析 ,检测…     

流动注射化学发光分析研究与应用进展

评述近年来流动注射化学发光分析法的最新进展。总结了流动注射化学发光中重要的化学发光试剂及其相应的新发光体系,概述了流动注射化学发光分析与特定的检测技术、分离技术结合形成的分析体系及其应用。     

现代仪器分析技术在潲水油检测中的应用

综述了近年来光谱、色谱、质谱、核磁共振等现代仪器分析技术在潲水油检测中的应用现状和发展,并对其应用前景进行了展望(引用文献46篇)。     

Large volume, low discrimination GC injection into a modified splitless injector

Summary A standard GC split/splitless injector was sealed with an airlock. The carrier gas and the sample were introduced through this valve. Such a configuration efficiently prevents an injector overflow. Injections up to 50 μL were made. An almost quantitative analyte and solvent transfer was observed, with only a minimal discrimination, of even volatile analytes. The use of an early vapor exit permitted a high initial liner flow and therefore a fast sample transfer.     

Study on characteristics of bias caused by FI-CE split flow electrokinetic injection

The characteristics of bias caused by split-flow electrokinetic injection (SEKI), a new type of sample injection method used in coupled flow injection-capillary electrophoresis system (FI-CE), was investigated using pseudoephedrine hydrochloride, a basic drug, and ibuprofen, an acidic drug, as model analytes. It was found that bias imposed by SEKI under the condition of continuous sample matrix/running buffer was similar to that done by electrokinetic injection (EKI). The linearity of calibration curve provided by SEKI was similar to that offered by non-bias hydrodynamic injection (HDI) but significantly better than that obtained by EKI. These features were exploited to improve analytical performances in simultaneous determination of the minor ingredient of pseudoephedrine hydrochloride and the major ingredient of ibuprofen in a pharmaceutical preparation. Detectability of 0.7 mg/l for pseudoephedrine hydrochloride was achieved at a sample throughput rate of 24 times per hour, which is 30% lower than that obtained by HDI-based conventional CE. Relative standard deviations (RSDs) of 2.8% for the minor ingredient and 1.2% for the major ingredient were produced in 11 runs of a test solution containing 13.1 mg/l pseudoephedrine hydrochloride and 81.4 mg/l ibuprofen. This is an improvement compared to that obtained by HDI-based conventional CE. Analytical results for two batches of compound ibuprofen tablets by the SEKI-based FI-CE approach were in good agreement with that obtained by a conventional high performance liquid chromatographic method. __________ Translated from Chinese Journal of Chromatography, 2005, 23(2) (in Chinese)     

Thermal degradation observed with different injection techniques: Quantitative estimation by the use of thermolabile carbamate pesticides

An experiment has been designed to study the thermal degradation of thermolabile compounds caused by various injection techniques. The four carbamate pesticides aminocarb, bendiocarb, carbaryl, and dioxacarb decompose thermally into methylisocyanate and the corresponding phenol. The carbamets and the phenols arising from them were separated on a 25 m SE-54 fused silica column; all compounds exhibited sharp peak shape indicating that the degradation observed took place completely within the injector. When cold on-column injection was employed no thermal degradation was observed whereas with hot splitless injection at 220°C decomposition of the carbamates was almost complete. PTV injection was found to produce intermediate results. When packed with glass wool and operated with glass wool and operated with starting temperatures lower than the boiling point of the solvent, decomposition was found to be almost complete. Applying isothermal conditions at 140°C (30°C above the boiling point of toluene) aminocarb and bendiocarb underwent only slight decomposition while carbaryl and dioxacarb were about half degraded. Results from PTV injection with an empty insert resembled those obtained using cold on-column injection and in this mode the application of temperatures up to 200°C resulted in no visible degradation. This can be explained by the short residence time of the sample in the injector.     

Stopped-flow injection analysis. The influence of diffusion on dispersion of normal and reverse flow injection

A relationship is derived to enable the comparison of the dispersion heights of normal and reverse flow injection analysis (FIA). A single channel flow system is employed in the absence of a chemical reaction. The stopped-flow injection method is used to probe the influence of molecular diffusion on the overall dispersion of normal and reverse FIA, which appeared to demonstrate fundamentally different diffusion behaviors. Small discrepancies are observed between the dispersion heights, which are enhanced by the stopped-flow period, especially when unmatched matrix ionic compositions of the indicator and counter solutions were involved. For these conditions, the diffusion flux rate is enhanced considerably, displaying a peak, in addition to the transient, for both methods. The influence of diffusion on the dispersion characteristics of normal and reverse FIA is discussed theoretically. Diffusion in the proposed model is postulated to oppose dispersion by convection. The latter initiates concentration gradients in the injection zone and propagates it with flow time over the dispersion zone profile. The diffusion flux then reacts in order to confine the indicator dispersion for normal FIA and to enhance it for reverse FIA. This model is consistent with the experimental results and accounts for most of the phenomena encountered. Probably owing to the influence of secondary flow phenomena, the use of coiled tubes has suppressed the effects of diffusion on the overall dispersion behavior.Part of the experimental work was performed at IMI Institute for Research and Development, Haifa, Israel.     

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

External injection of high-melting point low thermal conductivity ceramics orthogonal to a typical direct current thermal plasma jet plays a vital role in determining the in-flight state of the particles and the process downstream. The interactions between low density ceramic particles and high temperature plasma jet is quite complex, which influences the spray process and associated deposition. Detailed in-flight particle diagnostics as well as spray stream visualization have significantly enhanced our capability to diagnose and control the process. In this paper we present some salient observations on the role of key variables on particle injection. A number of experiments were conducted using a 7MB torch (Sulzer Metco, Westbury, NY) with both Ar–H₂ and N₂–H₂ plasma gases, where the carrier gas flow to inject Yttria Stabilized Zirconia (YSZ) was varied systematically and the resulting in-flight particle state was captured using an array of particle and spray stream sensors arranged in a 3D set-up. A notable observation is the existence of a “sweet-spot” in the plasma jet where the particle temperatures and velocities achieved a maximum. This sweet-spot can be characterized by the plume position (location of centroid of the spray stream) rather than carrier gas flow rate and is independent of primary gas flows and other process/material conditions. This result suggests a possible approach to optimize particle injection independent of plasma-forming-torch-parameters. Controlling particle injection at this sweet-spot has shown to benefit the overall process efficiency (in terms of melting) and process reliability (both in-flight measurement and coating build-up) with concomitant application benefits.     

Some recent developments on cost-effective flow-based analysis

This paper reviews some recent developments on cost-effective flow-based analysis. They include the newly developed Lab-at-Valve (LAV), concepts in using the stopped-flow injection approach, on-line sample pretreatment systems, including bead injection–flow injection and flow injection–ion-chromatography, systems for size-based speciation, and cost-effective reagents. Applications and advantages of such techniques are discussed.     

A comparative study of injection techniques in high-performance liquid chromatography

Summary The performance of injection valves with both curtain- and single-flow column couplings has been evaluated using reverse-phase octadecylsilane columns and a standard test mixture. The results are compared with those obtained from septum and stopped-flow syringe injections.Stopped-flow valve injection has been examined similarly. Configurations and couplings which give optimum efficiency and reproducibility are recommended.     

PTV splitless injection of sample volumes up to 20 μl

PTV splitless injection cannot compete with on-column injection as far as simplicity, reliability, and accuracy of quantitative analysis is concerned. However, PTV splitless injection is attractive for trace analysis of samples containing high concentrations of involatile sample by-products. Maximum injection volumes are limited by the amount of liquid that can be retained within the PTV injector chamber and are around 20–30 μl injected at once. Solvent evaporation must be carried out in such a way that injector overflow is avoided.     

流动注射-毛细管电泳分流式电动进样歧视效应特征的研究

以碱性药物盐酸伪麻黄碱和酸性药物布洛芬为对象研究了分流式电动进样(一种用于流动注射-毛细管电泳(FI-CE)联用系统的新进样方法)歧视效应的特性。结果发现:在样品介质与运行缓冲液一致的条件下,FI-CE分流式电动进样产生的歧视效应与电动进样相似,但获得的校正曲线的线性明显优于电动进样,而与没有歧视效应的压力进样所获得的线性相似。利用这些特征提高了同时测定复方布洛芬片中少量组分盐酸伪麻黄碱和主要组分布洛芬的分析性能。在24次/h的采样频率下,盐酸伪麻黄碱的检测限为0.7 mg/L,比采用压力进样的毛细管电泳法所得的检测限低30%。连续进样11次分析含有13.1 mg/L盐酸伪麻黄碱和81.4 mg/L布洛芬的试样溶液,峰面积的相对标准偏差分别为2.8%(盐酸伪麻黄碱)和1.2%(布洛芬),明显优于采用压力进样的毛细管电泳法。用该法测定了两批复方布洛芬片中两种组分的含量,所得结果与高效液相色谱法的测定结果一致。     

Comparison of soluble manganese(IV) and acidic potassium permanganate chemiluminescence detection using flow injection and sequential injection analysis for the determination of ascorbic acid in Vitamin C tablets

The limits of detection (3s) for ascorbic acid were 5×10⁻⁸ M with acidic potassium permanganate using both flow injection analysis (FIA) and sequential injection analysis (SIA) whereas the soluble manganese(IV) afforded 1×10⁻⁸ M and 5×10⁻⁹ M for FIA and SIA, respectively. Determinations of ascorbic acid in Vitamin C tablets were achieved with minimal sample pretreatment using a standard additions calibration and gave good agreement with those of iodimetric titration.