离子色谱法测量硝酸根和亚硝酸根国际比对研究

采用离子色谱法对1g/kg量级水平上CCQM-K59国际比对样品中的硝酸根和亚硝酸根校准溶液进行了准确测定。为进一步降低测定结果的不确定度、获得较高的准确度,以高纯硝酸钾和亚硝酸钠配置标准溶液。采用离子色谱法和电感耦合等离子体质谱法,分别对高纯硝酸钾和亚硝酸钠试剂中的主要阴离子和无机元素杂质进行了测定,采用归一化法扣除测定杂质,获得了准确的纯度值。在配置标准溶液时,对固体样品的称量进行了浮力修正;采用单点校准法测量国际比对样品中硝酸根和亚硝酸根的含量,以括号法校正仪器漂移。比对样品中硝酸根和亚硝酸根的含量分别为1.0172 g/kg和1.0139 g/kg,测定结果的相对扩展不确定度分别为0.11%和0.13%,获得了良好的国际等效一致性,在源头上保证了我国硝酸根和亚硝酸根检测领域的量值溯源。     

离子色谱法同时测定奶粉中亚硝酸根、硝酸根、氯离子和磷酸根

使用透析袋将溶解后的奶粉透析,用乙醚萃取,过C18柱分离后使用4.5 mmol·L-1Na2CO-3-4.5 mmol·L-1 NaHCO3作为淋洗液,用离子色谱法同时分离和测定了奶粉中亚硝酸根、硝酸根、氯离子和磷酸根.动态透析平衡时间只要1 h左右,四离子的离子色谱峰形较好,共存离子的干扰较小.峰面积与Cl-,PO3-4,NO-3及NO-2 4种阴离子浓度之间呈线性关系的相关系数依次为0.998 2,0.999 9,0.999 7及0.986 7,检出限(S/N=3)依次为9.36,15.0,0.1及0.02 mg·kg-1,测得4种离子测定结果的RSD值(n=7)分别为1.3%,2.6%,2.2%及7.3%.以3种奶粉为基体作加标回收试验,所得回收率均在92%以上.     

反相离子对色谱法同时测定水中的硝酸根和亚硝酸根

1　引　　言ＮＯ-3 和ＮＯ-2 是环境、食品等许多方面要检测的对人体有害的离子。同时测定ＮＯ-3 和ＮＯ-2 的方法有光度分析法、极谱法、色谱法等。色谱法具有试样前处理简单 ,样品用量少 ,分离速度快的特点 ,所以在分析化学中被普遍使用。ＮＯ-3和ＮＯ-2 在 2 1 0ｎｍ处均有较强的吸收 ,且吸收光谱严重重叠 ,难以用一般的分光光度法同时进行检测。我们采用反相离子对色谱法 ,以甲醇 /水 ( 2 0 /80 ,Ｖ/Ｖ)为流动相 ,四乙基溴化铵为离子对试剂 ,在ＯＤＳＣ1 8反相键合色谱柱上将它们进行分离 ,紫外光度计 ( 2 1 0ｎｍ)同时检测水中的ＮＯ-3…     

测定潮湿空气中粒子所含硫酸和硝酸根离子的方法

对复合薄膜法进行了改进，将人工粒子通过干燥器去除水蒸汽的不利影响，采集在镀有硝酸灵（Ｎｉｔｒｏｎ，Ｃ２０Ｈ１６Ｎ４）的膜片上。用真空镀膜法镀上氯化钡薄膜。用该法采集了高湿度下的大气粒子，对硫酸根和硝酸根两类粒子在透射电镜中进行观察，根据生成物的形态，测定出潮湿空气中粒子所含的酸性离子。     

一种新型的亚硝酸根离子选择性电极的制备及其特性

在一种特殊的钨酸空心管的基础上制备了一种结构简单且灵敏的亚硝酸根离子选择性电极。其线性响应范围是20ng/ml—5pg/ml NO_2~—,斜率约为68mV,此线性功能至少在电极连续使用时能保持三个月左右。电极的一些特性,如pH值的影响,选择性,响应时间,电极内阻,漂移,寿命及其存放等均已经过测试。该电极的是大特点是低至2.8×10~(-5),即大量的NO_3~—存在时一般不干扰NO_2~—的测定。     

毛细管离子电泳法同时测定腌菜中硝酸根和亚硝酸根

以溴离子(Br-)为内标,建立了毛细管离子电泳同时测定腌菜中的硝酸根和亚硝酸根的方法。讨论了缓冲液pH、样品和缓冲液中氯化钠浓度、分离电压对分离的影响。结果表明:以含1mol LNaCl的40mmol LH3PO4 NaOH缓冲-、-得到基线分离。NO3-和NO2液(pH3.5)为背景电解质,4min内Br-、NO3-检出限分别为0.1g L和0.3g L,峰面积相对标准偏差分别为4.6%和NO25 8%。     

硝酸根离子选择性电极的构建及研究进展

硝酸盐含量的检测对于评价环境中硝酸盐污染和了解生态系统氮循环方面起着非常重要的作用。离子选择性电极因操作简单、选择性好、方便携带、价格低廉等优点被广泛应用于环境样品中硝酸根的测定。本文从离子选择性电极功能材料、电极设计和实际应用三方面阐述了近20年硝酸根离子选择性电极的研究进展,汇总了新合成硝酸根离子载体的选择性性能,从固体接触传导层和离子选择性敏感膜组分角度分析了固体接触式聚合物膜硝酸根离子选择性电极的构建机理,总结了非聚合物膜硝酸根离子选择性电极的发展,并对硝酸根离子选择性电极在环境中的典型应用进行了介绍,以期为水环境和土壤中硝酸根的测定提供技术支持。     

提高硝酸根离子测量准确率

利用受污染严重浑浊带色的水样测定硝酸根,其研究方法相当多.平时经常遇到污染浑浊带色的水样,一般的处理方法是用活性炭吸附后过滤,但是由于活性炭对水样中的硝酸根也有较大的吸附作用,使测定结果严重偏低.因此必须寻找另一种方法,即能消除掉水样颜色又不影响其中的硝酸根.在这里我们采用紫外分光光度法来测定,并且要求水样不浑浊,不带颜色,否则会干扰测定结果.在酸性及煮沸的条件下,用KMnO4氧化水样中的各种生色有机物,过量的KMnO4以草酸钠溶液来还原,对其中的硝酸根离子没有造成影响.     

离子色谱法测定高锰酸钾中以及高浓度硝酸根中的高氯酸根

地下水和地表水中的高氯酸根危害人体健康。由于环境水样中的高浓度硝酸根和高锰酸钾基体干扰高氯酸根的测定,本方法通过滴加一定量的过氧化氢以除去高锰酸根,然后对样品进行离心来消除干扰。运用Dionex IonPac AS11型阴离子分离柱,流动相为8mmol/LKOH溶液,大体积(200μL)进样,抑制性电导检测器来测定有高锰酸钾以及高浓度硝酸根干扰的水中痕量高氯酸根。本方法的线性范围0.5~20mg/L,检出限为5μg/L。     

A Simple Method for Estimating Effective Ion Source Residence Time

A method is presented that uses the well-understood O₂/Ax ion-molecule reaction system to determine the effective ion source residence time of a chemical ionization source. The process consists of: (1) defining the kinetic system in terms of reactions, reaction rates, and ionization cross sections; (2) solving the differential equations that describe the time evolu-tion of the kinetic system, and (3) comparing the calculated results to experimentally measured relative ion intensities. These steps are repeated for a variety of 0₂/Ar sample ratios and inlet pressures. The method leads to a simple relationship between inlet pressure and effective ion source residence time, independent of the 0₂/Ar sample ratio.     

一种测定微量碘离子的简便偶合化学发光法

报道了在含Ｉ＾－的Ａｓ箩丹明Ｂ混合溶液中直接注射Ｃｅ＾４－，通过记录化学发光持续时间对微量Ｉ＾－进行定量的偶合化学发光法。检出限为６．０×１０＾－８ｍｏｌ／Ｌ，线性响应的浓度范围为１．０×１０＾－７－１．０×１０＾－５ｍｏｌ／Ｌ。该法简便易行，所受的干扰小，用于加碘食盐，酱油及实际水样中微量Ｉ＾－的测定，结果满意。     

A Simple and Rapid Method of Identification of Extracellular Plant Galactosidases

A simple, rapid, and sensitive procedure for the identification of plant extracellular - and -galactosidase is described using callus cultures of seedlings from the tested plant, roots of 4-6 day old seedlings of Californian poppy germinating on agar plates, and cell suspension cultures cultivated from callus cultures. Synthetic substrates were used for the determination of the intra- and extracellular activities of - and -galactosidase. Many imino- or azasugars are strong glycosidase inhibitors, and some of them show promising chemotherapeutic effects against viral disease and are potential antidiabetic as well as antitumor agents. This fact aroused our interest for a rapid and sensitive assay method of the activity of - and -galactosidases of plant origin. The results presented here show the perspective usefulness of extracellular galactosidases of plant origin in inhibitory and/or biotechnological studies.     

A Simple Fluorometric Method Using Chlorophyll a for Determination of Hg2+ Ion

A simple and green analytical procedure based on chlorophyll a is presented for the determination of Hg²⁺ ion. Chlorophyll a was extracted and purified from the leaves of pea and is employed as a reagent for analysis of Hg²⁺ ion. It displays remarkable fluorescence emission at 674 nm when excited at 412 nm. The emission intensity decreased significantly on exposure to various concentrations of Hg²⁺ ion. This forms the basis for the determination of Hg²⁺ ion. The proposed method was evaluated for sensitivity and selectivity. The linear concentration range was found to be 2.0–10 μM with r² = 0.997 and the limit of detection for Hg²⁺ ion was 1.3 μM. Ions including Pb²⁺, Cd²⁺, Ag⁺, Zn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Mg²⁺, Mn²⁺, Ru³⁺, Er³⁺, K⁺, Na⁺, NH₄⁺, Cl⁻, NO₃⁻, CH₃COO⁻ and SO₄²⁻ did not interfere with the measurement of Hg²⁺ ion even at 500-fold excess. Since chlorophyll a is widely available in the leaves of most plants, and the extraction and purification process is simple, this technique can provide an alternative, sensitive and economical way to determine Hg²⁺ ion.     

单柱型离子色谱仪改制双柱型离子色谱仪的简易方法

单柱型离子色谱仪改制双柱型离子色谱仪的简易方法宁君孔繁祚杜月宗李殿海（中国科学院生态环境研究中心北京１０００８５）（天津城市排水监测站３００３８１）高效离子色谱仪具有快速，灵敏，准确和方便地同时测定多种痕量的离子型，特别是阴离子型物质的独特优越性，已...     

A Simple and Environmentally Benign Nitration of Pyrazoles by Impregnated Bismuth Nitrate

We report herein a facile, rapid, and environmentally friendly synthesis of nitropyrazoles in good yields using silica‐bismuth nitrate and silica‐sulfuric acid‐bismuth nitrate at room temperature for the first time. The relatively non‐toxic nature, ease of handling, easy availability, and low cost make the present procedure attractive for the nitration of a wide variety of diazoles in the drug and pharmaceutical industries.     

“离子键”课堂演示实验的改进——碘化钠的简易制备

从教材中钠和氯气反应的演示实验出发,设计独特的实验装置,在实验室里完成了碘化钠的制备。避免了氯气的危害,也满足教学的需要。从热力学角度进行相关计算,证明本实验的可行性。     

离子色谱法测定水果中亚硝酸盐和硝酸盐

建立了离子色谱法测定水果中亚硝酸盐和硝酸盐的方法.试样溶液中亚硝酸盐和硝酸盐在YSA-8阴离子色谱柱分离,以4 mmol.L-1碳酸钠-3 mmol.L-1碳酸氢钠为流动相,电导检测.亚硝酸盐和硝酸盐的检出限分别为0.02 mg·L-1和0.11 mg·L-1,工作曲线的线性范围分别在0.2～20.0 mg·L-1和0.3～30.0 mg·L-1范围内.该方法已应用于水果中亚硝酸盐和硝酸盐的测定,测得回收率在93.4%～105.2%之间.     

离子色谱法测定消毒牛乳中的硝酸盐

硝酸盐很容易因细菌作用被还原成亚硝酸盐,食用后可引起中毒。消毒牛乳中往往含有硝酸盐,国家标准中把它定为评价消毒牛乳质量的重要指标之一。国家推荐标准的检测方法为化学法,该法繁琐复杂,且干扰因素多,误差大。本文将样品沉淀蛋白并离心过滤后,采用新型ICS-2000离子色谱仪测定消毒牛乳中的硝酸盐,不仅样品前处理简便、快速,且检测结果准确,与化学法有较好的一致性。     

A Simple and Rapid Method for the Identification of Amphetamine and Metamphetamine Hydrochlorides by Mass Spectrometry

Abstract

In order to determine amphetamine and metamphetamine, we have used a method never used before in the legal practice. The aim of our work was to optimize the measurement conditions for the rapid and accurate determination of amphetamine and metamphetamine. We have developed a method which makes possible the unambiguous identification of the hydrochlorides of the hallucinogens amphetamine and metamphetamine, even when these two are present simultaneously. In our work we have used the ammonium salt technique. The information available from the mass spectra (molecular ion, appearance of characteristic fragments) are dependent on the temperature of the direct sample and the ionisation energy. As a consequence, we have primarily studied the influence of the above two parameters upon the mass spectra.