酸性光亮镀铜溶液中氯化物的分析方法

在酸性光亮镀铜溶液中,Cl~-的多少对镀铜层质量有比较重要的作用,准确掌握镀铜溶液中Cl~-的含量,是当前酸性光亮镀铜急需要解决的问题。目前分析酸性光亮镀铜溶液中Cl~-。国内有些单位采用沉淀分离铜,用硝酸银直接滴定Cl~-。由于沉淀对Cl~-有一定的吸附性,测定结果的误差较大。根据这种情况,我们做了大量工作,终于试验出一种较快速的容量分析方法。分析Cl~-的方法如下。     

光亮镍镀液中硼酸含量的自动电位滴定

研究了光亮镍镀液中硼酸含量自动电位滴定的条件和方法。实验结果表明,用柠檬酸钾作掩蔽剂,防止Ni~(2+)的沉淀和其它重金属离子的干扰;加入丙三醇溶液,以pH复合电极为指示电极,进行自动电位滴定来测定硼酸,方法简便快捷,分析结果准确可靠。     

电位滴定法分析酸性光亮铜镀液中氯离子的含量

虽然酸性镀铜液中氯离子的分析方法有很多,但大都误差较大,或终点不明显,或试剂有干扰。本文介绍用电位滴定法来测定氮离子的含量,用硝酸银作为滴定剂,甩氯化银作指示电极,用甘汞作参比电极,用 pH 计或高阻直流毫伏计作电位滴定仪进行滴定,简便可靠,终点显示灵敏,结果也较精确。文内还附有高阻抗直流毫伏计的电路图供自制时参考。本法也可用于测定铝阳极氧化硫酸溶液中氯离子的含量。     

电位滴定法测定酸性镀锌溶液中氯化锌浓度

通过采用EDTA为滴定剂,钙电极为指示电极,双盐桥甘汞电极为参比电极,实现了酸性镀锌溶液中氯化锌含量的自动电位滴定.向待测液中加入Ca-EDTA(乙二胺四乙酸二钠钙)作为置换剂,增大了滴定终点时的电位突跃.实验考察了电极的种类、滴定剂预加体积、滴定剂的最大增量和最小增量、pH缓冲溶液和Ca-EDTA的加入量等对测定结果的影响,确定了最佳实验条件.本方法与手动滴定法的比对实验结果表明:两种测试方法测量数据基本一致.自动电位滴定方法准确可靠,测量过程简便快速,可以满足日常镀液分析的测定需求.     

离子选择电极法测定酸性光亮镀铜添加剂2-四氢噻唑硫酮

本文根据酮式和烯醇式含硫官能团,能与四氯化碳的碘溶液在吡啶作用下反应,并定量地释出碘离子的原理,采用硫化银离子速择电极作指示电极,双液接炮和甘汞电极作参比电极,用AgNO_3标准溶液进行电位滴定来测定酸性光亮镀铜添加剂2-四氢噻唑硫酮,测定结果与化学法进行了比较,两者测定的结果很接近,而本法电极系统响应快,而且不饱和化合物对测定无干扰。     

酸性镀铜液中硫酸铜的自动电位滴定

研究了用自动电位滴定法测定酸性镀铜液中硫酸铜的条件和方法。实验结果表明,在pH=10的氨-铵缓冲介质中,在Ca-EDTA共存下,以EDTA作滴定剂,用钙离子选择性电极作指示电极,以饱和甘汞电极作参比电极,滴定Cu2+,具有明显的电位突跃和清晰的滴定终点,该方法具有较高的准确度和精密度。应用于酸性镀铜液中硫酸铜的分析,方法简便快捷,能在4min内打印出结果。     

氰化镀铜液中游离氢氧化钠的自动电位滴定

研究了氰化镀铜溶液中,用自动电位滴定法测定氢氧化钠的条件和方法。实验结果表明,以pH复合电极为指示电极,设定滴定终点为pH=11.4时,共存的氰化钠、酒石酸钠及碳酸钠不干扰测定。操作简便快捷,7min内能打印出分析结果。     

油品中碱性氮含量电位滴定测定法

以高氯酸—冰乙酸溶液为标准滴定液,采用一支玻璃复合p H电极(非水相)代替传统的三电极进行电位滴定,用电位突跃自动判断滴定终点,建立了油品中碱性氮含量自动电位测定法。结果表明,相对标准偏差小于2%,方法重复性好,特别适合对小含量碱性氮油品及无合适指示剂深色油品的准确测定。     

渣油中碱性氮含量电位滴定测定法研究

以高氯酸-冰醋酸溶液为标准滴定液,采用玻璃复合电极进行电位滴定,用电位滴定曲线的电位突跃来判断终点,建立了渣油中碱性氮含量的测定方法.结果表明所建方法相对标准偏差小于2 %,方法重复性好,克服了因渣油颜色较深、没有合适指示剂确定滴定终点的缺点,可以用于测定渣油中碱性氮化物含量.     

用硫化银电极电位滴定海水中的氯

<正> 海水中氯(即氯离子)含量较高,用氯离子选择电极直接电位法测定误差较大,而且固态氯离子选择电极在海水中使用,产生长时间的漂移,造成了操作的困难。采用氯化银涂丝电极电位滴定法,虽有明显的电位突跃,但需要在丙酮介质中进行滴定。本文以硫化银电极作为指示电极,第二种离子选择电极为参比电极,组成无液体接界测量系统,对海水中高含量氯的测定进行了研究。试验表明,以氟离子选择电极或玻璃电极作参比电极,在酸性溶液中,电位突跃约140毫伏,终点明显,尤其是氟离子选择电极作参比电极,电位较稳定。实现了在酸性溶液中,不加有机试剂直接测定海水中高含量     

库仑滴定法测定生物乙醇制备原料的还原糖含量

利用库仑滴定法测定生物乙醇原料蔗糖的还原糖含量.样品经5 mL 10％盐酸于65-70 ℃水解15 min后,以铂电极为电解电极和指示电极,1.0 mol/L硫酸亚铁(pH 2.0)为电解质溶液,恒电流电解生成Fe3+,与预处理样品后生成的氧化亚铜定量发生氧化还原反应,记录电解至滴定终点时间,通过法拉第电解定律,计算样...     

高浓度∑Fe对硝酸银滴定法测定Cl-干扰的消除

采用硝酸银滴定法测定含高浓度铁离子溶液中的Cl-时,需要调整pH到6.5~10.5,产生氢氧化铁与氢氧化亚铁沉淀,影响滴定终点的判定,导致分析结果不准确。本研究在含不同高铁浓度模拟溶液中加入氢氧化铝胶体洗涤出铁离子,再用硝酸银滴定法分析Cl-浓度,结果显示在Cl-浓度20 mg/L时,相对偏差小于5%,浓度为200 mg/L时,相对偏差最大为1.03%,并把该方法应用在分析花岗岩铀矿浸出液中的Cl-浓度,与采用选择氯离子电极法分析结果对比,结果表明了这两种方法的分析结果相差不大。因此该方法消除高铁对硝酸银滴定法分析氯离子是可行的。     

Adsorption of Cd(II) ions at the hydroxyapatite/electrolyte solution interface

The study of the Cd(II) ions adsorption at the hydroxyapatite/electrolyte solution interface and the changes of the electrical double layer (EDL) structure in this system are presented. The adsorption of Cd(II) ions was calculated from the loss of their concentration from the solution using the radioisotope method. The adsorption was studied in the range of the initial concentration from 0.000001 to 0.001mol/dm³ and as the function of pH. The results of measurements of Cd(II) ions adsorption kinetics on hydroxyapatite were fitted using the pseudo-first, pseudo-second, and multiexponential modes to check which model describes this process in the best way. In addition, the main properties of the EDL, i.e., surface charge density and zeta potential were determined by the potentiometeric titration and electrophoresis measurements, respectively. The adsorption of Cd(II) ions at hydroxyapatite contributed to the increase of the zeta potential and also to the change of the double electrical layer structure.     

电位滴定法测定标准物质DIANP的纯度

为了定值标准物质DIANP,建立了测定DIANP纯度的电位滴定法.该滴定法的条件是:DMSO作溶剂,NaOH溶液作反应试剂,使DIANP中的N-3和AgN03中的Ag+反应,生成AgN3沉淀.由EQP曲线算得标准物质DIANP纯度为99.85％,相对标准偏差为0.13％,与液相色谱法比较,结果无显著差异,该方法的扩展不...     

NaCl溶液中铜和A_3钢接触腐蚀的研究

研究了金属铜与A3钢在NaCl溶液中偶接时的接触腐蚀行为。考察了偶接时间、溶液中Cl-浓度、电偶对中阴阳极面积比、实验温度等因素对阳极腐蚀速度的影响。结果表明,腐蚀速度随温度升高、溶液中Cl-浓度的增大、阴阳极面积比的增大而增大;偶接时间为24 h时,腐蚀速度趋于稳定。     

自动电位滴定仪在铜元素分析中的应用研究

利用自动电位滴定仪,建立了铜合金和铜矿石中铜含量检测的一种新方法。结果表明：用二阶微商法确定滴定终点为245 mV,在预控点设置为310 mV,滴定剂硫代硫酸钠标准溶液浓度为0.01 mol/L滴定,pH在3～4之间时,加入2 mL氟化氢铵,取10 mL消解液的滴定结果较接近,且标准偏差较小,精密度高,测定结果准确。     

A novel method for the determination of acid value of vegetable oils

The voltammetric behavior of naphthoquinone in the presence of free fatty acids (FFA) at the polypyrrole (PPy)‐modified electrode was investigated in an ethanol/1,2‐dichloroethane (3 : 1) solution containing 0.1 M LiClO₄. A well‐defined new reduction peak appeared at a more positive potential and was higher than that obtained at the bare Pt electrode. Based on the fact that the new reduction peak current showed a good correlation with the concentration of fatty acids, an electroanalytical method for the acid value (AV) of vegetable oils was developed using the PPy‐modified electrode in linear potential sweep voltammetry. The experimental parameters were optimized to obtain a sensitive voltammetric response in this work. A linear calibration graph was obtained in the concentration range of 5.0×10^–6–6×10^–3 M for FFA (R = 0.993), with a sensitivity of 2.41×10^–2 A L/mol and a detection limit of 1.2×10^–6 M (S/N = 3). Each assay of vegetable oil sample took about 80 s. The developed method is applied to the AV determination of six commercial vegetable oils. The results well agreed with those obtained by the titration method. Compared to the conventional titration method, the proposed method is superior in sensitivity and accuracy and requires a small amount of vegetable oil sample, with no pretreatment.     

Potentiometric Determination of Alkyl Dimethyl Hydroxyethyl Ammonium Surfactant by a New Chemically Modified Carbon Past Electrode

This paper introduces the development a new chemically modified carbon paste electrode (CMCPE) for the determination of a cationic surfactant. The paste is based on alkyl dimethyl hydroxyethyl ammonium chloride (ADHACl) with phosphomolybdic acid as an ion‐exchanger (ADHA‐PM). The electrode exhibits a Nernstian slope of 59.1 ± 0.5 mV/decade for ADHA ions in the concentration range 1.0 × 10^?6–1.0 × 10^?3 M with the limit of detection of 8.2 × 10^?7 M. The proposed electrode has a fast and stable response time of 5–8 s, a good reproducibility and it can be used in the pH range of 2.2–9.0. Selectivity coefficients, determined by a matched potential method and separate solution method, showed high selectivity for ADHA over a large number of inorganic cations and organic cations. These characteristics of the electrode enable it to be used successfully for determination of ADHA in shampoo and liquid detergents solutions by standard addition and the calibration curve methods. In addition, the modified electrode was applied as an indicator electrode in potentiometric titration and successfully used to determine ADHA in water samples with satisfactory results.     

铜电极电位滴定法测定氢氧化镁

以HG／T3607—2000为基础，研究了用Metrohm 798 MPT Titrino全自动电位滴定仪测定氢氧化镁中镁离子质量分数的方法，铜电极为指示电极，银／氯化银为参比电极。与人工滴定比较，具有操作简便、分析速度快、终点判断准确的特点，受环境及溶液温度的影响小。并用基准氧化镁对该方法进行了验证。     

三电极电位法测定聚酯中端羧基含量

采用三电极电位法 ,对以苯酚 -四氯乙烷为溶剂测定聚酯中端羧基进行了实验和探讨 ,并建立了端羧基测定的新方法 ,此方法的相对标准偏差为 2 78% ,可用于聚酯中端羧基测定