理学D/MAX—1400全自动X射线衍射仪真空及其控制电路故障部位判定和排除

在简要介绍真空控制流程图的基础上,选择了TMP轴承受损、TMP叶轮打烂、电路参数改变TMP加速过快OLL报警烧保险、转靶磁密封不良VAC1报警、供电缺相过流保护和真空控制放大器自激离子规衰老等6个有代表性的、已排除的故障实例进行深入分析研究,提出了排除故障的思路和方法。     

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。     

碳硫分析专用复合催化剂的研制

美国力可公司高频红外碳硫测定仪采用镀铂硅胶催化剂来提高碳分析精度并防止ＳＯ２对ＣＯ２测定的干扰，将ＳＯ２转化为ＳＯ３除去。但镀铂硅胶价格昂贵，消耗量大，本文采用过渡金属氧化物和稀土氧化物在一定条件下，利用活性氧化物混合法新工艺，研制成碳，硫分析专用复合催化剂。     

肾上腺素在亚甲绿碳糊修饰电极上的电催化氧化及流动注射分析

将亚甲绿浊混合在碳糊中制成化学修饰电极对肾上腺素的氧化具有良好的电催化作用，降低Ｅｐ氧化过电位４００ｍＶ。该电极用于流动注射分析能大大提高Ｅｐ的检测灵敏度。     

Amperometric Determination of Bilirubin with Flow Injection Analysis System

Abstract

The amperometric method using the flow injection system has been developed for the determination of bilirubin. Bilirubin is oxidized to biliverdin at the glassy carbon working electrode. The optimum conditions were investigated. Linear calibration curve was obtained between 1.0×10⁶ and 1.0×10^?3M, with a sampling rate of 20 samples h^?1 and a relative standard deviation of 3.2%. The limit of detection is 4.0×10^?7M. Interference of hemoglobin was not observed.     

空气整段间隔流动注射分析中分散度影响因素及性能研究

空气整段间隔流动注射分析中分散度影响因素及性能研究支正良，田笠卿（中国药科大学分析计算中心，南京，２１０００９）（南京大学现代分析中心，南京，２１０００８）关键词空气整段间隔流动注射分析，分散度，铁空气整段间隔ＦＩＡ［１，２］的特点是将注入的试样带首...     

Application of A Multichannel Potentiostat to Metal Ion Determinations in Flow Injection Analysis

Abstract

A 4-channel potentiostat has been developed for use with an amperometric array and applied to the determination of a mixture of metal ions in flow injection analysis (FIA). The use of an array facilitates the acquisition of three dimensional electrochemical information in real-time (current vs. potential vs. time). The data acquired can be saved in ASCII format which facilitates post-run plotting of the 2-and 3-D voltammograms in Microsoft Excel. The results demonstrate the increased information content available with an amperometric array over fixed potential electrodes. The ability to identify the individual species in mixed component injections, which is normally not possible with FIA without a prior separation step has been demonstrated. Linear responses to injections of copper(II) ions in the concentration range 500 ppm to 100 ppb were obtained.     

Isatin Analysis Using Flow Injection Analysis with Amperometric Detection – Comparison of Tetrahedral Amorphous Carbon and Diamond Electrode Performance

Isatin is an endogenous indole compound in humans and rodents that has a wide range of biological activity. In rat models, isatin concentrations have been shown to increase in the heart, brain, blood plasma, and urine with stress. Studies on patients suffering from Parkinson's disease have indicated a correlation between progress of the disease and urinary output of the molecule. Isatin is electrochemically active and can therefore be detected with electrochemical techniques. In this work, we compared the performance of a nitrogen‐incorporated tetrahedral amorphous carbon (ta‐C:N) and a boron‐doped nanocrystalline diamond thin‐film electrode for the oxidative detection of this biomolecule using flow injection analysis with amperometric detection. The measurements were performed in 0.1 phosphate buffer pH 7.2. The ta‐C:N electrode, like boron‐doped nanocrystalline diamond, exhibits some excellent properties for electroanalytical measurements including (i) low background current and noise, (ii) microstructural stability at positive detection potentials, and (iii) good activity for a wide range of bioanalytes without conventional surface pretreatment. The results reveal that both electrodes exhibit a linear dynamic range from 100 to 0.1 μmol L⁻¹, a short‐term response variability 3–4 % RSD (30 injections), a sensitivity of 18 mA M^‐1, and a limit of detection (S/N=3) of 1.0×10⁻⁷ mol L⁻¹ (14 ng mL⁻¹ or 2.5 fmol).     

片段流动分析法测定水中氨氮

利用被亚硝基铁氰化钠催化的铵(NH4 )与次氯酸盐和碱性苯酚溶液三者之间反应所生成的蓝色络合物(靛酚蓝)(λmax=660 nm)和应用FS-Ⅳ型流动分析仪,对水中氨(包括铵)氮作光度测定。对该方法的灵敏度、准确度和精密度进行了试验。测得的检出限、相对标准偏差及回收率值依次为0.003 mg.L-1,<2%及在90%~111%范围间。     

Assessment of Additives for Nitrogen, Carbon, Hydrogen and Sulfur Determination by Organic Elemental Analysis

 A survey is reported on the use of additives in organic elemental analysis of compounds containing functional groups that may compromise the combustion process. 28 substances containing the following functional groups were selected: organic fluorine, hexafluorophosphate, tetrafluoroborate, tetraphenylborate, sulfonate, phosphine, nitrile, carbide, organometallic. Six additives (powdered silver, silver tungstate with magnesium oxide, silica oxide, tungsten (VI) oxide with magnesium oxide, powdered tin, cerium (IV) oxide) in various sample:additive ratios were assayed. Silver tungstate with magnesium oxide (mixture 1:1, w/w) turned out to be most efficient for the analysis of nitrogen, carbon, hydrogen and sulfur for almost all the compounds assayed. Author for correspondence. Received August 2, 2002; accepted December 12, 2002 Published online May 19, 2003