Measurement of trace nitrate concentrations in seawater by ion chromatography with valve switching

An ion chromatographic method with a valve switching facility was developed to determine trace nitrate concentrations in seawater using two pumps, two different suppressors, and two columns. A carbohydrate membrane desalter was used to reduce the high concentrations of sodium salts in samples. In this method, trace nitrate was eluted from the concentrator column to the analytical columns, while the matrix fl owed to waste. Neither chemical pre-treatment nor sample dilution was required. In the optimized separation conditions, the method showed good linearity( R >0.99) in the 0.05 and 50 mg/L concentration range, and satisfactory repeatability(RSD<5%, n =6). The limit of detection for nitrate was 0.02 mg/L. Results showed that the valve switching system was suitable and practical for the determination of trace nitrate in seawater.

Determination of inorganic anions in ethyl acetate by in-line hollow fiber membrane extraction with ion chromatography

In this work, a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water. Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time. Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfactory linear range, limits of detection and good repeatability were obtained. The procedure was applied to analyze inorganic anions in two commercial ethyl acetate samples.

Separation of Inorganic Anions Using Methacrylate-Based Monolithic Column Modified with Trimethylamine in Ion Chromatography Capillary System

Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.

Organic acids and inorganic anions in Bayer liquors by ion chromatography after solid-phase extraction

A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.

Determination of sulfur anions by ion chromatography-postcolumn derivation and UV detection

A novel method for determination of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate in foodstuffs by ion chromatography separation with postcolumn derivation and UV detection has been developed. All species are separated at Dionex IonPac AG22A and AS22A with mobile phase of a mixture of 4.5 mmol/L sodium carbonate and 0.8 mmol/L sodium bicarbonate at a flow-rate of 1.0 mL/min. The postcolunm derivation solution was 0.24% iodine in 0.2% phosphate acid and the detection wavelength was set at 288 nm. The detection limits （LOD, signal-to-noise ratio of 3） of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate were 0.004, 0.006, 0.006, and 0.007 mg/L, respectively. Within-day relative standard deviations （RSD, n = 10） of formaldehyde sulfoxylate, sulflte, thiocyanate, and thiosulfate were 3.24%, 3.76%, 2.68%, and 2.07%, respectively. The recoveries of the four anions were in the range of 67.2-116.5%.

INVESTIGATION ON SEPARATION OF INORGANIC ANIONS BY REVERSED-PHASE ION-PAIR LIQUID CHROMATOGRAPHY

Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chromatography with indirect UV detection or conductivity

离子色谱法测定玉溪北城“涩水”中4种无机阴离子

为了研究玉溪市北城“涩水”中无机阴离子的含量是否符合《生活饮用水卫生标准》中的限值,采用离子色谱法测定了玉溪北城“涩水”中F^(-)、Cl^(-)、NO_(3)^(-)、SO_(4)^(2-)的含量。结果表明,玉溪北城“涩水”中1月、2月、3月和4月的F^(-)、Cl^(-)、NO_(3)^(-)、SO_(4)^(2-)四种无机阴离子含量低于《生活饮用水卫生标准》中的限值。该方法标准曲线相关系数在0.9990以上,样品加标回收率在93.73%~109.20%之间,检出的数据准确可靠。结果为进一步探究“涩水”的水源保护和商用价值开发提供了数据支撑。

微波萃取–离子色谱法测定TSP中常见阴离子的方法研究

利用离子色谱结合微波萃取技术建立了总悬浮颗粒物(TSP)中常见无机阴离子(F^(–)、Cl^(–)、NO_(3)^(–)、SO_(4)^(2–))的快速分析检测方法。实验结果表明:当大气采样体积为60 m^(3),样品制备体积为20 mL时,方法检出限为0.033~0.067μg/m^(3),相对标准偏差在2.7%~5.2%,加标回收率在98.8%~102.2%。该检测方法应用范围宽,重现性好,易于操作,快速准确。

Alkaloid Accumulation in Catharanthus roseus Increases with Addition of Seawater Salts to the Nutrient Solution

A sand culture experiment was conducted to determine the effects of different seawater (5% and 10%) treatments on plant growth,inorganic ions,indole alkaloid concentrations and yields of Catharanthus roseus,in an effort to increase the alkaloid yield by artificial cultivation.The total fresh and dry weights and tissue K + concentrations decreased,but Na + concentrations increased in the plant roots,stems and leaves of C.roseus under seawater stress as compared to the control.The concentrations and yields of vindoline,catharanthine,vinblastine and vincristine increased under seawater stress.The concentrations and yields of these alkaloids were higher in 5% seawater-treated plants than those in the 10% seawater-treated plants.Considering the industrial production,5% seawater treatments could reduce the cost of producing alkaloid.In the control plants,the highest alkaloid concentrations reached a peak at 100 days after planting,suggesting that plant harvest must be optimized in terms of growth duration.

快速连续提取沉积物中还原性无机硫的实验方法与应用

还原性无机硫是沉积物硫中最活跃的部分,其含量变化控制沉积物中铁、磷及重金属等元素的地球化学行为,在地质过程和环境污染方面都具有至关重要的影响。化学连续提取法是目前沉积物中硫形态提取基本方法,但常用的冷扩散法处理单个样品耗时长,难以实现对大批量样品的快速连续提取。为实现快速、准确地测定沉积物样品各形态还原性无机硫的含量,本文采用热蒸馏法,改进基于前人的三步提取过程,通过优化实验装置预先制备实验所需的二氯化铬溶液,实现了样品还原性无机硫形态的快速连续提取;以过氧化氢为氧化剂,将提取的各形态硫氧化为SO2-4后采用离子色谱进行检测。选取三峡库区沉积物样品进行重复实验检验,得到提取酸挥发性硫、黄铁矿硫、元素硫的标准偏差(RSD,n=3)分别为5.26%、1.22%和3.09%,重复性较好。进一步对酸挥发性硫、黄铁矿硫、元素硫的加标回收率进行测定,得到这三种硫形态的回收率分别为92.8%、93.6%、94.1%。本实验方法采用的热蒸馏法对单个硫形态提取时间为1.5h,用时较短,玻璃装置连接便捷、操作简单,分析检测准确度好,实现了一套装置对沉积物还原性无机硫形态的连续提取,可适用于大批量样品的硫形态快速提取与检测。

自搭建离子色谱仪及其在无机阴离子检测方面的应用

为了帮助学生深入理解化学分析仪器的构造和工作原理,训练学生的创新思维、实践能力和团队协作能力,增强学生在化学分析仪器相关的基础实验中的参与感,设计了可供学生自行搭建离子色谱仪的新创实验,并将其应用于无机阴离子的检测。实验包含具有完整功能的离子色谱仪整机以及关键部件“电化学离子抑制器”的组装搭建,仪器基本功能的调试和性能测试以及自来水、湖水和茶水等实际水样中阴离子的定性和定量检测。该项目采用商品化的标准组件和自行加工的部件来搭建仪器,实验复现性高,还可以有效训练指导教师专业综合素质,显著提升基础实验教学效果和水平。与商品化整机比较,价格低廉,对教学经费投入要求低,适合在高校中化学及相关专业的仪器分析基础实验教学中推广。

离子色谱法测定盐湖沉积物中可溶性阴离子

盐湖沉积物中可溶性阴离子提取和测试方法对其实验结果至关重要,但不同的前处理提取和测试条件缺乏系统的对比和优化。通过对比水浴加热、超声提取、涡旋振荡三种前处理条件的提取效率,发现涡旋振荡离心的前处理方法回收率最佳,并进一步优化了水土比例、涡旋振荡离心方法的浸提时间和浸提次数。在离子色谱测试中发现以30 mmol/L KOH溶液作为淋洗液,流速1 mL/min,柱温30℃,电导检测器进行离子色谱分析效果最佳。最终建立了以涡旋振荡离心为前处理提取,离子色谱法测定盐湖沉积物中四种无机可溶性阴离子(F^(-)、Cl^(-)、SO_(4)^(2-)和NO_(3)^(-))的检测方法。结果表明,四种阴离子检出限≤0.026 mg/L,线性相关性良好R2≥0.998,加标回收率为80.0%~114%,精密度RSD为0.64%~1.3%,具有快速准确、灵敏度高、简单可靠等优点,通过对6份西藏地区盐湖表层沉积物样品进行分析,发现Cl_(-)和SO_(4)^(2-)是主要的阴离子成份,与湖泊盐度趋势基本符合。方法可适用于高盐度盐湖沉积物样品中无机阴离子的测定。

固相萃取净化-离子色谱法测定不同生长期新鲜烟叶中的7种无机阴离子

为了研究不同生长期新鲜烟叶中无机阴离子的含量和变化规律,建立了一种固相萃取净化-离子色谱法测定新鲜烟叶中的,7种无机阴离子(F^(-)、Cl^(-)、Br^(-)、NO_(2)^(-)、NO_(3)^(-)、SO_(4)^(2-)、PO_(4)^(3-))的方法。样品经0.1 mol/L NaOH水溶液超声提取,萃取液经RP1.0cc固相萃取柱净化后,使用AS11-HC(4 mm×250 mm)色谱柱进行分离,以KOH为流动相,梯度洗脱。结果表明,7种无机阴离子在0.10~5.0μg/mL范围内具有较好的线性(r>0.996),检出限在0.01~0.04μg/mL,定量限在0.04~0.14μg/mL,加标回收率为96.3%~102%,相对标准偏差(RSD)在2.7%~4.8%。方法前处理操作简单,7种无机阴离子分离好,检测灵敏准确,可用于不同生长时期新鲜烟叶样品中多种无机阴离子含量的检测分析。

离子色谱法在饮用水和食品检测中的应用

离子色谱是分析离子的一种液相色谱技术,因具有快速、简便、准确、灵敏度高的优点,广泛应用于多个领域。本文主要介绍离子色谱法在检测饮用水中无机物、食品中营养成分及食品添加剂中的应用,以便为更深入的研究奠定基础。

馆藏砖石质文物有害盐中多种无机及有机酸阴离子的定量分析

博物馆环境空气中无机或有机酸性污染气体会腐蚀馆藏砖石质文物并使其表面出现有害盐。常见的有害盐种类复杂,可能同时含有无机和有机酸阴离子。为进一步认识文物盐害和分析盐害产生的原因,本研究建立了一种基于离子色谱的有害盐中无机和有机酸阴离子定量分析方法。该方法可同时测定馆藏砖石质文物上有害盐中氟离子、氯离子、溴离子、硝酸根、亚硝酸根、磷酸根、硫酸根、甲酸根、乙酸根、丙酸根、丁酸根、戊酸根等十二种阴离子。采用2~30 mmol/L KOH淋洗液梯度洗脱,能够在35 min的检测时间下实现该十二种阴离子的快速分离与准确检测。所有阴离子的标准曲线的相关系数均高于0.995,检出限为0.001~0.022μg/mL,定量限为0.004~0.073μg/mL;加标回收率为81.8%~107.0%。该方法采用超纯水作为溶剂,样品处理简单,易于操作;具有成本低廉、检测时间短和准确性高的特点;可定量计算有害盐中多种无机及有机酸阴离子的质量分数。将该方法应用于中国国家博物馆馆藏“汉并天下”瓦当和仿制玉炉表面有害盐中的无机及有机酸阴离子的分析,可为分析盐害发生的原因,阻止、延缓及预测盐害的发生提供依据。

氧化燃烧离子色谱法测定原油总氯含量

原油样品经准确量取注入样品舟,必要时经二甲苯稀释,直接进入氧化燃烧离子色谱仪测定总氯含量。总氯在1.0~50 mg/kg浓度范围内呈良好线性,线性相关系数达0.9994,相对标准偏差为2.44%~4.70%,总氯的检出限为0.092 mg/kg,回收率在90.9%~109.8%之间。本方法具有样品处理简单,结果准确等优点,适用于批量原油总氯的快速检测。

贵州威宁草海中阴离子含量的测定

采用离子色谱法对草海水体中F^(-)、Cl^(-)、NO^(-)_(2)、Br^(-)、NO^(-)_(3)、H_(2)PO^(-)_(4)、SO_(4)^(2-)等7种无机阴离子进行了分析测定。实验结果表明:标准曲线相关系数均大于0.997,相对标准偏差为1.568%~3.750%,试样加标回收率为93.5%~111.7%。各河段水样中F-质量浓度值小于1 mg/L,符合国家Ⅱ级标准(GB 3838—2002),其余Cl^(-)、NO^(-)_(3)、NO^(-)_(2)、Br^(-)、H_(2)PO^(-)_(4)均符合国家Ⅱ级标准,SO_(4)^(2-)最大质量浓度为90.42 mg/L,小于中国地表水标准限值。

底栖鱼类对水田上覆水中磷素动态的扰动效应(摘要)(英文)

[目的]研究底栖鱼类泥鳅对水田上覆水中磷素动态的扰动效应,探讨生物扰动机制。[方法]基于模拟试验,使用离子色谱法和分光光度法,对比分析上覆水中磷素含量在有/无泥鳅活动时的差异。[结果]扰动组的TP、DTP和PP浓度在试验开始阶段与对照组无显著差异,在试验中、后期显著高于对照(P<0.05)。扰动组的PP/TP高于对照组,扰动组中TP浓度的增加主要是由于PP的增加。扰动组的DIP/DTP在试验中、后期显著高于对照(P<0.05)。[结论]底栖鱼类对水田上覆水中的磷素产生了扰动作用,增加了水稻生长可利用的磷素养分。

离子色谱法测定柴油车尾气处理液中8种无机盐含量

本文建立离子色谱法同时测定柴油车尾气处理液中氟化物、氯化物、亚硝酸盐、溴化物、硝酸盐、磷酸盐、亚硫酸盐和硫酸盐8种无机盐的方法。采用纯水稀释、固相萃取柱纯化、直接过膜前处理技术进行样品的处理。以4.0~6.0 mmol/L碳酸氢钠溶液为淋洗液,经AS23型阴离子分析柱分离,电导检测器检测。结果表明,8种无机盐在各系列浓度范围内与色谱峰面积具有良好的线性关系,相关系数为0.9995~0.9999,检出限为0.0052~0.0521 mg/L。该方法的回收率为83.0%~111.7%,相对标准偏差为0.2%~4.9%。该方法具有样品前处理简单,操作简便快速、灵敏度高、分离度好的特点,适用于柴油车尾气处理液中8种无机盐含量的检测分析。

离子色谱法测定聚乙二醇6000中有机酸和无机阴离子

目的建立离子色谱法测定聚乙二醇6000中的10种有机酸和无机阴离子含量。方法采用IonPac AS11-HC(250 mm×4 mm,9μm)分析柱,以KOH淋洗液进行梯度洗脱,柱温30℃,流速1.0 mL·min^(-1),进样量25μL,选择电导检测器进行测定,外标法定量。结果在该色谱条件下,10种有机酸和无机阴离子的峰面积与质量浓度的线性关系良好(r≥0.999),平均回收率为93.4%~100.6%,RSD为0.60%~2.6%。结论本方法检出限低、重现性好,可用于聚乙二醇6000中有机酸和无机阴离子含量的控制。