共查询到18条相似文献,搜索用时 171 毫秒
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在酸性介质中用氟电极测定氟离子的新方法 总被引:1,自引:0,他引:1
基于弱酸根离子在不同酸度溶液中的化学平衡和离子选择电极的响应特征, 本文推导出了以氟电极为指示电极, 玻璃pH电极作参比在酸性介质中测定氟的新方法. 经验证: 当pH<2时, 氟离子浓度在10^-2~10^-5 mol/L范围内, 电池电动势值与氟离子总量呈能斯特响应, 试液中少量铝的存在对测定不构成干扰. 用该法直接测定了酸蚀法铝型材废水中的氟, 加标回收率达96%~98%. 相似文献
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用电化学沉积法将铋离子修饰在玻碳电极上,应用此铋膜修饰玻碳电极测定镓时,将试液在pH 5.4的六次甲基四胺-盐酸缓冲溶液中在-1.30 V处预还原40 s,然后在-1.30~-0.50 V范围内扫描,使镓离子从修饰电极上溶出,实现了镓离子的溶出伏安法测定,在-1.01 V处可得镓离子的氧化峰电位,镓的质量浓度在0.002 8~0.21μg.L-1范围内与其峰电流值呈线性关系,方法的检出限(3S/N)为0.7 ng.L-1。方法用于测定铝箔中镓的含量,加标回收率在98.2%~103.8%之间。 相似文献
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建立一种可同时测定混合卤素离子的电位滴定新方法.在这种方法中,滴定剂是硝酸银和氟化钠的混合溶液,被滴定液中同时插入了氟离子指示电极和银离子指示电极.在滴定过程中的任一滴定点,溶液中Ag 的浓度和滴定剂的加入体积可由两个电极的电位测定值同时获得,从而可应用多元校正法由相应的滴定曲线求得混合卤素离子中每一种离子的含量.用该方法对混合物样品中的Cl-、Br-、I-进行了同时测定,测定结果的相对标准偏差为0.13%~0.45%(n=5),回收率为97.3%~103.4%. 相似文献
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测定平衡常数多采用电导法、冻点法或反应速率法等。用离子选择电极测定平衡常数或离解常数多集中研究各种氟络合物。用硫电极测定平衡常数的工作仅见到测SnS_3~(2-)的平衡常数。我们在对硫电极研究的基础上,用pH玻璃电极测定溶液的pH值,用pS电极测定不同pH值溶液中的[S~(2-)]浓度,根据H_2S在溶液中的平衡理论及硫电极在溶液中的响应特性,找到一种推算H_2S离解常数的途径。 相似文献
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《Analytical letters》2012,45(12):879-883
Abstract In the determination of fluoride ion with a fluoride ion-selective electrode, tiron is the most effective of masking agents tested for aluminum. The higher the pH, the more effective the masking, but the hydroxide ion raises the lower limit of determinable fluoride ion concentration at higher pH. Therefore, measurements at pH 6.0 are preferable. Fluorine in two glass samples has been successfully determined with tiron. 相似文献
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A new method for determining iron is based on both nonlinear regression calibration plots and parabolic interpolation using a fluoride ion-selective electrode (ISE) and the Apple II-ISE intelligent ion Analyzer developed by ourselves. The experimental conditions for determining iron are discussed. The appropriate acidity of the experimental solution is pH 3, controlled by total ionic strength adjustment buffer (TISAB) that is composed of glycine (aminoacetic acid), nitric acid and sodium nitrate. The suitable total concentration of fluoride is equal to the highest concentration of iron in the standard series. Because the mathematical model of the method coincides with the experimental data the Apple II-ISE intelligent ion Analyzer can perform data acquisition and data processing, and the performance of fluoride electrode is excellent, the new method for determination of iron is fast and accurate. This method has been used successfully in the determination of iron in mineral samples. 相似文献
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A new solid state fluoride ion selective electrode composed of 70% Ag2S, 10% Cu2S and 20% CaF2 has been developed. An analytically useful potential change occurred, from 1 × 10−6 to 1 × 10−1 M fluoride ion. The slope of the linear portion (1 × 10−1-1 × 10−5 M) was about 26 ± 2 mV/10-fold concentration changes in fluoride. It was found that pH change between 1 and 8 had no effect on the potential of the electrode. There was no interference of most common cations such as K+, Na+, Ca2+ and Mg2+ and anions such as Cl−, NO3−, SO42− and PO43−. The lifetime of the electrode was more than 2 years, when used at least 4-5 times a day, and the response time was about 60 s.The measurements were made at constant ionic strength (0.1 M NaNO3) and at room temperature. This electrode has been used for the determination of fluoride ion in Ankara city tap water and in bottled spring water using standard addition method. The validation of the electrode has been made with a commercial fluoride ion selective electrode (Orion) and high consistency was obtained. 相似文献
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In this work a construction procedure for tubular fluoride electrode to be used in flow systems is outlined. The electrode was constructed from a commercially available, LaF3 single crystal. Principal advantages of the flow detector presented include simplicity of construction, robustness, durability, low cost and easy coupling into any point of a flow manifold.Evaluation of the intrinsic working characteristics of the potentiometric detector in a low dispersion manifold is presented with respect to analytical and dynamic parameters. The constructed detector has similar working characteristics to those of the conventional fluoride electrodes, namely the detection limit, lower limit of linear response and operational pH range.The analytical usefulness of the constructed device was assessed in a flow system developed for fluoride determination in toothpaste, tablet, collutory and water samples for which the reference procedures suggest the determination of fluoride ion with a conventional ion selective electrode. 相似文献
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采用离子选择电极法对生活饮用水中氟化物浓度进行了测定。讨论了水样中pH值、温度、响应时间对测定结果的影响。在最佳条件下,方法的线性范围为0.10~3.0mg/L,相关系数为0.9999,检出限为0.05mg/L,实际水样加标回收率为97%~106%,相对标准偏差(n=5)为0.04%~0.65%。方法简单快速,干扰小,重现性好,加标回收率令人满意,能进行生活饮用水中氟化物浓度的有效测定。 相似文献
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基于2,3-丁二酮双缩氨基硫脲为中性载体的新型银离子选择性电极的研究 总被引:1,自引:0,他引:1
研究了基于2,3-丁二酮双缩氨基硫脲为中性载体的聚氯乙烯(PVC)膜电极, 该电极对银离子(Ag+)具有优良的电位响应性能. 在pH=3.0的NaOH-HNO3体系中, 该电极对Ag+电极电位呈现近能斯特响应, 线性响应范围为3.0×10-6~1.0×10-2 mol/L, 斜率为52.6 mV/decade (20 ℃), 检测下限为1.0×10-6 mol/L. 相对于常见的阳离子, 该电极对Ag+表现出良好的选择性. 采用交流阻抗技术研究了电极响应机理, 并将电极初步应用于回收率实验, 结果令人满意. 相似文献
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《Analytical letters》2012,45(10):699-708
Abstract A method has been developed for the determination of sodium in alumina using a selective ion electrode. The alumina sample is dissolved in ammonium hydrogen fluoride in platinum crucibles or sintered with boric acid using either platinum, nickel, or zirconium crucibles. Either dissolution technique completely extracts all available sodium. After dissolution, and in the presence of citrate to prevent aluminum hydroxide precipitation, the pH is adjusted to 8.7 with ammonium hydroxide, and the sodium concentration is determined by a sodium selective ion electrode. 相似文献
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Elimination of fluoride ions in water for human consumption using hydroxyapatite as an adsorbent 总被引:2,自引:0,他引:2
V. E. Badillo-Almaraz J. Armando Flores H. Arriola F. A. López L. Ruiz-Ramirez 《Journal of Radioanalytical and Nuclear Chemistry》2007,271(3):741-744
In this work, a synthetic hydroxyapatite, Bio-gel HTP, marketed by BIO-RAD®, has been studied in order to propose a method to remove the excess fluoride present in drinking water. The removal of fluoride ions by this adsorbent has been studied as a function of solution pH, and fluoride ion concentration. Experiments of fluoride ions sorption have been carried out with the use of 18F radiotracer in solutions of NaF at several concentrations with an ion selective electrode used for fluoride analysis. The adsorption isotherms show that the best fluoride adsorption on hydroxyapatite occurs at a pH range of 7.0–7.5. At this pH value the solid presents an important capacity of subtraction of fluoride, of around of 100 mmol/100 g. 相似文献