用离子选择电极测定硝盐包覆层的痕量阴离子表面活性剂

工业上一般生产的硝酸钠和亚硝酸钠会产生结块现象,影响使用质量。若在结晶母液槽中加入一定浓度的阴离子表面活性剂十二烷基苯磺酸钠(DBS),在晶粒界面能生成包覆层,可防止结块。如何控制监测结晶槽中痕量 DBS 的浓度,将是生产过程的关键。由于大量的 NO_3~-或 NO_2~-离子的存在,对测定痕量阴离子表面活性剂的次甲基兰比色法和电位滴定法带来干扰。本文用液膜型阴离子洗涤剂电极(AD 电极),研究了在0.01～0.20MNaNO_3或 NaNO_2电介质溶液中 DBS 的临界胶束浓度(CMC)的变化规律和电极的线性响应范围,建立了直接电位法测定硝盐包覆层的痕量阴离子表面活性剂。当 DBS 浓度为     

氟离子选择电极测定尿氟正常值

氟及其无机化合物进入人体经代谢后,主要随尿排出,因此尿氟量的测定对氟中毒的预防,对了解工人接触氟的程度和评价氟对生产环境的污染以及对氟中毒的诊断等都有较大的价值。但由于一些食物及饮水中含有微量氟,并随地区不同而有差异,加之人们的生活环境,饮食习惯的不同,因此各地区正常人尿氟含量是不相同的,为探索南京地区尿氟正常值,我们应用国产氟离子选择电极对313名正常人进行了尿氟测定。一、对象的选择选择了居住在南京一年以上,年岁20—60岁,身体健康,没有氟接触史的工人、解放军,学生、干部共313名正常人,其中男性187名,女性126名。     

氟锆酸离子选择电极的研制

氟锆酸钾在镁铝合金,光学玻璃原料及陶瓷材料等方面广泛应用,也可用作锆化合原料,催化剂。目前生产单位用繁杂的重量法分析在酸性条件下,把氟锆酸钾转化为二氧化锆,费时费力。研制能直接测定氟锆酸根浓度的离子传感器,对缩短分析时间,减轻操作人员的工作负担具有重要意义。氟锆酸电极的研制在国内外杂志上未见发表过。本文研制的 PVC 膜电极以四十二烷基氟锆酸铵为活性材料,邻苯二甲酸二(2——乙基己)酷为增塑剂,在各方面都具有较好的性能,本电极检测下限为6.76×10~(-5),酸度影响较小。     

氟离子选择电极作为温度传感器的尝试

氟离子选择电极在各个领域得到了广泛的应用。作者利用氟离子选择电极电位对温度敏感的特点,选择碘—亚砷酸—硫酸铈催化温度反应体系,在无外界隔热的条件下,成功的利用氟离子选择电极电位的变化来指示滴定终点。并利用于空气汞的检测中。一、测定原理恒定条件下,离子选择电极的温度变化可由能斯特方程对温度微分得到:d_E/d_T=d_(Eο)/d_T+0.1984T/n·dlg[F~1]/d_T+0.1984/n 1g[F~-]温度对电位影响由三部组成:d_(Eο)/d_T,标准电位的温度系数项,是特定的电极特性,     

离子选择电极法测定锡精矿中氟

该文研究了用离子选择电极在柠檬酸钠-硝酸钾-三乙醇胺体系测定锡精矿中氟的测定方法,讨论了该体系pH对电位的影响、TISAB掩蔽锡量、铝量及其它干扰元素的影响,该方法测定的相对标准偏差小于1.67%,回收率为98%～102%.     

PVC膜电极对表面活性剂响应的实验研究

在广泛使用表面活性剂的今天,将聚合物离子选择电极用于测量表面活性剂,是一个有实用价值的课题,可望实现对环保工程中的监控和工业流程中的质量控制.人们曾对此进行了大量的工作,但对有些问题的看法至今尚无定论.为此,我们研制了几种膜电极,分别对Cl~-,Ba~(2+)和一系列阴离子、非离子表面活性剂进行测试,比较了各自响应规律的异同点,并从理论上对响应机理进行了探讨.     

离子选择电极法测定尿结石中微量氟

在０．５ｍｏｌ／ＬＨＣｌＯ４介质中，采用氟离子选择性电极测定了尿结石中的微量氟。校正空白值后，Ｆ＾－的线性范围为１．００×１０＾－２－４．７９×１０＾－７ｍｏｌ／Ｌ。本法的相对标准偏差和回收率分别为０．７５％和１０１．１％。六例尿结石的氟含量为２６４３±２１０４μｇ／ｇ，这表明氟化物对尿结石的形成有促进作用。     

离子选择性电极测定龙牡壮骨冲剂中的微量氟

龙牡壮骨冲剂是一种强筋壮骨，疗效较好的纯中药制剂。本文采用氧瓶燃烧－离子选择性电极法首次测定了该制剂的氟含量。结果表明，该制剂不仅含有丰富的钙质，还含有较高的微量元素氟，这有利于人体钙质吸收，骨骼发育和钙磷代谢，为研究其药用功效提供了理论依据。     

离子选择电极法测定铅精矿中微量氟

用氟离子选择电极以多次标准添加作图法测定了铅精矿中微量氟离子,铝、铁等阳离子的干扰,可由柠檬酸根和EDTA络合消除.方法简单、快速,相对标准偏差小于5.0%(n=6),加料回收率为98%～102%,最低可测定0.001%的氟离子.     

氟离子敏场效应管的研制

阐述了一种氟离子敏场效应晶体管(FISFET)型传感器的结构和工作原理。它是在pH ISFET传感器的基础上用PVC方法把离子敏场效应晶体管和氟化物敏感膜相结合,制成氟离子敏场效应晶体管。该传感器具有全固态化 体积小的特点。实验表明该传感器的灵敏度为50mV/C,响应时间:小于1min,相关系数为0.9842,对氟化物的检测范围:1×10-6～1×10-1mol/L。     

基于掺杂聚吡咯的硝酸根离子选择性电极

研究了一种基于硝酸根掺杂聚吡咯技术的硝酸根离子选择性电极。该电极以玻碳电极为载体,以包含硝酸根离子的聚吡咯薄膜为电极敏感膜。在含有硝酸根离子浓度数量级为10-4.5,10-4.0,10-3.5,10-3.0,10-2.5,10-2.0mol/L的硝酸钠测试溶液中,电极的响应电势呈现出较为理想的线性关系,且电势斜率值接近于理论值,符合能斯特响应规律;电极操作简便,具有较短的响应时间和较好的重复性。该电极的研发成功,为当前环境水质监测中总氮的实时监测提供了一种有效的解决方案。     

Performance evaluation of copper ion selective electrode based on cyanocopolymers

A copper(II) ion selective electrode based on copper(II) salicylaniline Schiff's base complex in styrene-co-acrylonitrile copolymer (SAN) has been developed. The SAN-based membrane electrode containing copper(II)–Schiff's base complex, dioctylphthalate as plasticizer and sodium tetraphenylborate as an anion excluder exhibited a linear response with a Nerstian slope of 30 mV decade⁻¹ within the concentration range of 10⁻⁶–10⁻² mol dm⁻³ of Cu²⁺ ions. The prepared electrode has an average response time of 15 s to achieve 95% steady potential for Cu²⁺ concentration ranging from 10⁻⁴ to 10⁻² mol dm⁻³. The electrode has shown a detection limit of 10⁻⁷ mol dm⁻³ of Cu²⁺ ion with an average lifetime of 6 months. The selectivity of electrode for Cu²⁺ ion has been found to be better in comparison to other various interfering ions. The electrode is suitable for use within the pH range of 2.0–7.0 at 1.0×10⁻³ mol dm⁻³ of Cu²⁺ ion. The prepared electrode can be used successfully as an indicator electrode for the potentiometric titration of the Cu²⁺ ion using EDTA.     

The effect of idle time thresholds on computer use time estimations by electronic monitoring

This study examined the effect of idle time setting on the estimation of computer use times by electronic activity monitoring and validated its use by comparing it with video record observations. Twenty-four study subjects were recruited and their work with computers was monitored for 1 h. With the estimates by video record observation as references, the best idle time settings for electronic activity monitoring with the least relative errors were 25, 2.5 and 2.5 s, respectively, for total computer, keyboard and mouse use time estimations. These estimates were highly correlated with the corresponding references (r = 0.918–0.964, p < 0.0001), accompanied by limited mean estimate differences ranging from ?3.0 ± 2.8% to 1.3 ± 1.6%. The estimates by self-report were moderately correlated with the corresponding references (r = 0.387–0.678), with greater mean estimate differences. This study concluded that, for electronic activity monitoring methods, the most appropriate thresholds for idle time setting are 25 s, 2.5 s and 2.5 s for total computer, keyboard and mouse use time estimates, respectively. This method may help evaluate physical work-loading with computer works through a large-scale epidemiological study.     

Web服务响应时间测试

随着Web服务技术的不断发展和广泛应用,需要运用测试技术来保障Web服务的正确有效运行,而Web服务响应时间则是评估Web服务质量最直观的一个参数.基于Apache axis,解析WSDL,用CTM产生有效测试例,实现Web服务的实时测试、不同站点测试、负载测试、平均响应时间测试.测试表明程序运行稳定,测试的结果为评估Web的服务质量提供了有力的参考.就授权测试、多个Web服务测试方面还需完善的工作做了进一步探讨和展望.     

Selectivity tune of fluoride ion sensing for phenolic OH-containing BODIPY dyes

A series of BODIPY dyes bearing phenolic OH in the meso-phenyl moiety were designed and synthesized for colorimetric and fluorescent detection of F⁻ ions by way of O-H?F hydrogen bonding interactions. Both the electron-donating group attached on the meso-phenyl skeleton, such as methoxy group and t-butyl group, and the substituting position of the phenolic OH have dramatic influences on the chemical shift of OH, pK_a of OH, and the binding constant of OH to F⁻. The binding selectivity to F⁻ over other anions may be greatly improved by down-regulating the binding constant to F⁻ through structure optimization. As a result, BODIPY 7 can selectively probe F⁻ in both absorption and fluorescence modes in acetonitrile and does not response to other anions including AcO⁻. The observed structure dependence of the binding selectivity may provide guidelines for the development of new F⁻ colorimetric or fluorescent sensors of high selectivity.     

锌离子选择电极及其检测微量元素的实验研究

锌离子(Ⅱ)在低浓度时不易保持其自由离子的形态,以Zn络合平衡的基本原理为基础,结合采用Visual MINTEQ软件进行计算,讨论了Zn在溶液体系中的存在形态,从而获得稳定的低浓度的自由锌离子。通过锌离子选择电极(Zn-ISE)对所配置的缓冲溶液体系标定可知,在自由锌离子浓度高于10-8mol/L时,Zn-ISE仍然能够正常测量,从而将Zn-ISE的测量下限从10-5mol/L扩展到了10-8mol/L。     

以聚苯胺与无机盐复合物为载体的离子选择电极

有机-无机杂化材料因具有二者的优势在新型敏感材料领域引起了人们的广泛关注.根据近期研究工作和国外最新文献,系统论述了聚苯胺-无机盐复合物的离子选择交换与络合能力,重点评述了由聚苯胺-无机盐复合物作活性载体制成的离子选择膜电极的特性.指出聚苯胺-磷酸锡、聚苯胺-磷酸砷锡、聚苯胺-钨酸砷锡复合物分别对He2 、Pb2 和Cd2 具有较好的交换与络合能力,在其它离子共存时,对上述三种离子的选择系数均远远大于1.将该复合物作为活性载体制作的离子选择电极对重金属离子如Hg2 、Cd2 具有很高的灵敏度,能斯特斜率与理论值29.6 mV/decade相近.响应时间均不超过40 s,探测下限可低至10-6 mol/L,且线性范围较宽,共存离子基本无干扰.     

The effect of grid size on street location time in maps

Two experiments investigating the time taken to locate roads in an urban map are described. The data support the hypotheses that road location time is (a) linear on the reciprocal of the distance between grid lines, and (b) linear on the number of roads per grid square. The issue of the optimal distance between grid lines is discussed and it is argued that for the particular map investigated, this distance should represent 0·25 km.