测汞仪自动化进样系统

采用自主研发的软件控制精密注射泵,并结合化学还原汞标准溶液方法,可解决目前台站监测设备测汞仪溯源困难的问题。对比分析了手动操作和自主设计自动化进样系统在测汞仪标校过程中的测试结果。通过线性曲线和重复性试验,表明自动化进样与手动操作测量都体现出极好的线性度和重复性。自动化装置和人工操作判定系数R2为0.997和0.996,重复性分别为1.8%和2.2%,表明了自动化装置测试结果比手动操作精度更高。自动化进样系统操作起来更简便、易实行,降低了工作人员的操作强度,不仅提高了工作效率,减少因操作时间过长造成的汞标准物质失效,还可避免汞源对人体的直接危害。     

单纯形自动优化的顺序注射分析系统

报道了具有自动优化功能的微机控制的顺序注射光度分析系统的研制。系统主要由注射汞、十位选择阀和带流通池的分光光度检测器构成。操作参数设定、数据采集和处理通过微机完成。采用改进单纯形方法进行系统优化,其算法集成到ＳＩＡ系统控制程序中使优化过程在微机的控制下自动完成。系统研究了ＳＩＡ钼蓝法测磷的操作条件对结果的影响。     

复杂酸碱平衡系统的信号流图解法

用两种方法构建了二元酸平衡系统信号流图,应用信号流图操作规则对图操作,得到了关于二元酸平衡系统的正确计算结果.建立表示混合酸碱平衡系统信号流图,由图能简捷准确给出酸碱任意混合时溶液的[H ]精确式.     

最新安捷伦1100系列微盘液相系统的特点 简单的方法设定、简便的操作和省时的维护

简单的方法设定、简便的操作和省时的维护1100系列微盘液相系统可由Agilent三维化学工作站和手持控制器同时控制操作,二者均提供简单易学的图形化操作界面,便于初学者掌握。该系统同时包括快速安装和入门软件、计算机辅助操作认证的成套软件、各种校正功能和标准操作规程等内置功能,保证用户工作轻松。安捷伦公司同时还提供各种附件,以增强系统操作的灵活性和适应性,如:各种微盘,包括96位微盘、384位微盘和96位深孔盘安捷伦Zorbax快速分析柱(3.5μm),为各种分析应用提供最快的分析方式,缩短分离时间,降低运行成本最新安捷伦1100系列微…     

微流控芯片系统中固液双相分离富集技术

发展微流控芯片系统中的分离富集技术，是微全分析系统向集成化、自动化和便携化发展必须突破的瓶颈之一，正逐步成为微全分析系统研究和应用领域的前沿和热点。本文针对重要而且应用广泛的固液双相分离富集技术，详细介绍了过滤式、膜分离式、固相萃取式等不同分离富集操作模式在微流控芯片系统中的应用，对每一种操作模式的特点、研究现状、存在的问题和发展趋势进行了综述。     

新型“大型仪器自主操作资格”获得机制探索

探索建立了一种新型"大型仪器自主操作资格"获得机制。仪器使用申请者在分析测试中心仪器预约平台上提出申请,运用虚拟实验训练系统进行针对性自主培训。通过无人监督考核后,预约上机操作考核,2项考核均合格即可获得申请使用仪器的自主操作资格。该获得机制的核心是运用虚拟实验训练系统进行自主培训,具有很强的适用性、针对性和灵活性,尤其适用于申请者专业背景和操作水平有较大差异的状况。该机制可有效促进开放式共享平台管理模式的科学优化,切实提高大型仪器的使用效率,为实验学科的教学改革提供新的思路。     

复杂电渗泵系统的输液特征

基于对电渗泵中压强产生原理的讨论, 对新兴的复杂串、并联电渗泵系统的流体输液特征加以研究. 在多级串联电渗泵系统中, 可以通过增加电渗泵的级数或操作电压来提高泵系统产生的压强, 但是单一流路的输液能力有限. 而在多级并联电渗泵系统中, 输液量也可以通过增加电渗泵的级数或操作电压得到提高. 在这一体系中, 尽管输液量的叠加有利于其在更为广泛的领域中应用, 但是因Joule热产生的电场强度与电渗流速度线性关系的偏离也使得其线性范围变小, 不利于操作条件的控制.     

毛细管电泳分离过程的不可逆热力学模型及优化控制仿真

以非平衡热力学分离理论为框架,建立了毛细管电泳分离大系统的分离模型。以分离过程的操作电压U为控制量,以溶质体系的净分离熵S~S作为目标函数,通过对分离大系统的优化设计,得到了最优操作电压控制轨线U^*(t)。通过仿真,证明了分离大系统在此最优控制规律作用下,分离效果最好。     

基于内扩散有效因子测定实验的3D虚拟仿真实验预习系统设计

催化剂内扩散有效因子测定实验是大学基础实验之一,传统的实验预习方法注重理论介绍,不能给学生以直观的感受和操作体验,导致学生对实验设备、操作步骤比较陌生。针对此问题,设计出一种基于3D虚拟仿真技术的实验预习系统,用操作3D虚拟仿真实验模型的方式来提高学生的实验预习效果。此系统还能基于一种惩罚扣分评分模型进行考核,能够对操作数据进行统计分析,不仅帮助学生加深对实验的理解,而且有利于提高教学质量。     

微流控芯片高通量试样引入系统的研究

基于微流控芯片试样引入技术的研究是目前微流控芯片分析领域内的重要研究方向之一,其目的是实现宏观外部系统(进行10^-6～1L级液体的操作)与芯片系统(进行10^-12～10^-9 L级液体的操作)的衔接(world-to-chip interfacing)．目前文献报道的微流控分析系统,包括芯片流动注射系统,     

Pulsed discharge photoionization detector: Application to analysis of chloro alkanes/alkenes

A windowless pulsed discharge photoionization detector (PDPID) is described which uses the emission spectra from the discharge in helium and Ar/Kr doped helium. The emission from helium is a continuum ranging from 13.5–17.7 eV which ionizes all compounds except neon. The emission from 5.4% Ar/He ranges from 9.3–11.8 eV and ionizes most organic compounds and many inorganic compounds. The emission from 1.36% Kr/He consists principally of the resonance lines at 10.6 and 10.1 eV. These PDPIDs are used to analyze a 12 component mixture containing principally chloro alkane/alkene. The relative responses of the PDPID combined with the relative retention time can be used to qualitatively identify the chloro compounds.     

Supported capillary membrane sampling-gas chromatography on a valve with a pulsed discharge photoionization detector

The objective of this study was to develop and evaluate a simple miniaturized approach to gas chromatography termed supported capillary membrane sampling-gas chromatography on a valve (SCMS-GCOV). The prototype instrument uses a pulsed discharge photoionization detector (PDPID) as the GC detector. Two different analyzers were constructed. The first used a bench scale SCMS-GC. The second was a miniaturized SCMS-GCOV analyzer. The SCMS-GCOV analyzer was used to monitor the concentrations of trihalomethanes (THM4) in drinking water. Details are given for the construction of the SCMS-GC-PDPID and the SCMS-GCOV-PDPID analyzers. The results of method detection limit, accuracy and precision studies are reported for analysis of THM4 and are compared to other methods of THM4 analysis. Side-by-side comparison studies are conducted between the SCMS-GCOV and USEPA 502.2 with promising results.     

Determination of trihalomethanes in water samples: a review

This article reviews the most recent literature addressing the analytical methods applied for trihalomethanes (THMs) determination in water samples. This analysis is usually performed with gas chromatography (GC) combined with a preconcentration step. The detectors most widely used in this type of analyses are mass spectrometers (MS) and electron capture detectors (ECD). Here, we review the analytical characteristics, the time required for analysis, and the simplicity of the optimised methods. The main difference between these methods lies in the sample pretreatment step; therefore, special emphasis is placed on this aspect. The techniques covered are direct aqueous injection (DAI), liquid-liquid extraction (LLE), headspace (HS), and membrane-based techniques. We also review the main chromatographic columns employed and consider novel aspects of chromatographic analysis, such as the use of fast gas chromatography (FGC). Concerning the detection step, besides the common techniques, the use of uncommon detectors such as fluorescence detector, pulsed discharge photoionization detector (PDPID), dry electrolytic conductivity detector (DELCD), atomic emission detector (AED) and inductively coupled plasma-mass spectrometry (ICP-MS) for this type of analysis is described.     

Use of dual-column fused-silica capillary gas chromatography in combination with detector response factors for analytical toxicology

Retention and detector response factor data have been given for 188 compounds on the DB1 capillary column using a dual nitrogen--phosphorus and flame ionization detection system. Factors affecting the detector response factor parameter in a dual-capillary column system have been discussed showing its advantage in drug screening.     

Coulometric detector based on porous carbon felt working electrode for flow injection analysis

A coulometric detector based on carbon felt as working electrode has been designed. Ascorbic acid, hydroquinone, gallic acid and sulfur dioxide were used as electroactive compounds to determine the electrochemical characteristics of this detector. The coulometric conversion efficiency, selectivity, linear response range, detection limit and mass transfer coefficient were investigated in order to use the detector as a cleanup device in a flow injection system with dual-detector. This system has been used for determination of sulfur dioxide in wine, and the results are compared to those from the aspiration-oxidation method.     

Analytical calculation of the collimated detector response for the characterization of nuclear waste drums by segmented gamma scanning

Improved methods for the reconstruction of the isotope specific activity content in nuclear waste drums with data obtained by a gamma scanning system developed at Shanghai Jiao Tong University require an analytical function of the detector response. In this work we derive an analytical detector response function for a collimated HPGe detector with a square collimation window. The model is based on a purely geometric model respecting the configuration of the collimated detector system, the positions of radioactive point sources and the absorption of γ-rays in the matrix as well as in the HPGe crystal. We show that the derived analytical detector response function is in good agreement with data simulated by MCNP5.     

Some Possibilities and Limitations of Contactless Impedimetric Determinations of Organic Liquids in Aqueous Solutions. The Interference from Ionic Compounds

The possibilities of impedimetric determinations of organic liquids in mixtures with aqueous solutions have been studied in detail, using a planar capacitor cell combined with multivibrator and operational amplifier circuits functioning as a differentiator and a system of dioxane with aqueous solutions of alkali halides. The experimental values have been compared with a simple model and the detector response has been characterized. The behaviour of the detection cell can be reliably predicted on this basis. This approach permits extremely simple, rapid and cheap analyses of binary liquid mixtures, however, it suffers from a serious limitation in that the overall electric conductivity of the mixture must be low.     

A new light emitting diode-light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

A new system for CO₂ measurement (0–100%) based on a paired emitter–detector diode arrangement as a colorimetric detection system is described. Two different configurations were tested: configuration 1 (an opposite side configuration) where a secondary inner-filter effect accounts for CO₂ sensitivity. This configuration involves the absorption of the phosphorescence emitted from a CO₂-insensitive luminophore by an acid–base indicator and configuration 2 wherein the membrane containing the luminophore is removed, simplifying the sensing membrane that now only contains the acid–base indicator. In addition, two different instrumental configurations have been studied, using a paired emitter–detector diode system, consisting of two LEDs wherein one is used as the light source (emitter) and the other is used in reverse bias mode as the light detector. The first configuration uses a green LED as emitter and a red LED as detector, whereas in the second case two identical red LEDs are used as emitter and detector. The system was characterised in terms of sensitivity, dynamic response, reproducibility, stability and temperature influence. We found that configuration 2 presented a better CO₂ response in terms of sensitivity.     

Identification of the constituents of a complex mixture by combined use of retention indices and specific multidetection responses

The ratio of the responses of two different specific detectors to a single compound has, when used in conjunction with the compound's retention index, been investigated as an identification criterion for the compound. The ECD:NPD and ECD:FPD response ratios have been used for the identification of some pesticides. Analyses were performed with a single column – dual parallel detection – personal computer system. The reliability of the detector response ratio (DRR) was demonstrated by the consistency of detector response with time, and the influence of the quantity of analyte and of the chromatographic operating conditions. These factors were selected in the expectation that the technique could be used for routine trace analysis.