微型自动光度滴定法测定铜矿中铜

建立了微波辅助消解-微型自动光度滴定法测量铜的方法。用4个有证标准物质验证方法的准确度,回收率为99.8%～99.9%。与经典方法相比,该法更加快速、准确,适合于铜矿石中Cu的测定。     

光度滴定法测定苦土中钙

在pH为10的NH_3-NH_4Cl缓冲溶液中,以紫脲酸铵为指示剂,于505nm波长处用EGTA光度滴定苦土试液中钙,获得满意结果(CV<4％,加标回收率为99.5％～100.8％)。     

光度滴定法在分析化学中的应用

摘要：介绍了光度滴定法的基本原理和装置,综述了光度滴定法在食品、药品、化工等领域的应用情况。我国光度滴定法大多是通过浸在溶剂中的光度电极的电位变化来确定滴定终点,操作复杂;国外则是自制光度滴定仪系统,可以实现无校正曲线情况下的定量,自动化程度更高。因此,在推进光度滴定技术在分析化学中应用的同时,我国还需要开发一系列集合溶剂流路控制系统和高精度光度计的全自动滴定装置,以满足食品、药品、化工等领域快速检测、批量检测的要求。     

流动注射—光度滴定法测定锌净化液中锌

用流动注射光度测定法实现了锌净化液中高含量锌的快速自动测定，方法简单，虽仅采用传统的ＥＤＴＡ和锌的配合反应，以二甲酚橙为指示剂，但借助在制的ＣＰＡＣ－Ⅲ型分析仪，达到了运用微量分析的手段进行常量分析的目的，方法直接应用于测定锌净化液样品，分析速度为每小时测定６０个样品，结果令人满意。     

电位滴定法测定铁中间合金中铁含量

建立了铁中间合金中铁含量测定的自动电位滴定法,考察了溶样体系、还原剂类型及用量、滴定环境和共存离子干扰等因素的影响。结果表明,硝酸、过氧化氢和氢氟酸对测定结果有较大的影响,在滴定前应去除;磷酸会导致三氯化钛水解,影响测定结果,应避免引入;共存的Cr, Co和Cu等金属离子对测定结果没有影响。在1%～99%含量范围内,方法的相对标准偏差（RSD）为0.08%～0.26%。使用硅铁、锰铁和钕铁硼等有证标准样品验证了方法的准确度。该方法解决了可视滴定方法存在的滴定终点颜色干扰问题,减少了磷酸等试剂的用量,规避了分离干扰离子的复杂操作,简化了实验步骤,同时提高了铁含量测定的精密度。     

半自动催化光度滴定法测定生物样品中的锰

报道了以催化光度返滴定法来测定锰含量的新方法 .以EDTA作络合剂 ,Mn(II)为返滴定剂 ,滴定终点由锰 (II)催化高碘酸钾氧化结晶紫的褪色反应来指示 .在体系中加入表面活性剂 (TritonX - 10 0 )可改善反应条件 ,使测定可在室温下进行 ,用半自动化装置使操作连续、快速、简便 .用该方法测定鸡肝、人发、啤酒中的锰含量 ,结果与原子吸收光谱法所得结果相吻合     

流通池光度滴定法应用：多元络合物组成的快速测定

用流通光度滴定法建立了测定多元络合物组成的快速方法。方法简单，仅用中心离子和配体各一个标准溶液。经测定几组络合物体系，实验结果与文献值完全一致。     

非水光度滴定法测定钢中低碳

研究了非水滴定定碳法中非水吸收液的组成、指示剂的配比及滴定终点时溶液色泽的吸光度变化。结果表明,由乙醇、乙醇胺及不饱和多胺组成的非水体系对钢样燃烧时所释出的二氧化碳能最有效的吸收。试验选择了百里酚酞和茜素黄R的混合液为滴定指示剂,能给出敏锐的终点指示。在此基础上设计了一套非水定碳的自动分析装置。无论自动仪器或手工操作所得的分析结果都与标准值符合。方法应用于低含量碳的测定。     

Rapid photometric determination of phosphorus in iron ores and related materials as phosphomolybdenum-blue

A rapid, simple and accurate method for determining phosphorus photometrically in iron ores and related materials, obviating the use of perchloric acid, is described. The sample is fused with sodium peroxide in a zirconium crucible and the melt dissolved in hydrochloric acid. The molybdenum-blue complex is developed by the addition of ammonium molybdate and hydrazine sulphate and the absorbance is measured at 725 nm. The range of the method is from 0.005 to 1.0% P. A batch of 6 samples can be analysed in about 2 hr.     

Rapid method for the photometric determination of manganese in ores and alloys

Summary A procedure for the rapid photometric determination of manganese in the range of 4–24 mg/50 ml, is based on the oxidation of manganese(II) to manganese(III) by excess potassium dichromate in a medium of 8.0 to 9.0 M phosphoric acid at room temperature. Interferences are few when compared to the methods currently available. The method can be successfully employed for the estimation of manganese in ores and alloys and the results obtained compare favourably with standard methods. The method is therefore recommended for adaption for rapid routine analysis.

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Schnelle Methode zur photometrischen Bestimmung von Mangan in Erzen und Legierungen

Zusammenfassung Ein Verfahren zur raschen Bestimmung von Mangan im Bereich von 4–24 mg/50 ml wird beschrieben. Es beruht auf der quantitativen Oxydation von Mn(II) zu Mn(III) mit Dichromat in 8,0–9,0 M phosphorsaurer Lösung bei Raumtemperatur. Die Störmöglichkeiten sind geringer als bei sonst üblichen Methoden. Das Verfahren wurde mit Erfolg zur Manganbestimmung in Erzen und Legierungen angewendet und gute Übereinstimmung mit Standardmethoden erzielt. Es wird für die schnelle Routineanalyse empfohlen.

     

Silver-reductor method for determination of iron in iron ores and iron-ore sinters

A new technique for the quick dissolution of iron ore, magnetite and sinter products has been developed. The sample is dissolved with thioglycollic acid and hydrochloric acid, the excess of thioglycollic acid is oxidized, and the iron is reduced in the silver reductor.     

Direct photometric titration of tellurium

A direct photometric titration method has been developed for the determination of tellurium. Tellurium(IV) is titrated with potassium dichromate in 2-6M nitric acid (or 1-4M perchloric acid) at 380-430 nm (blue-violet filter). Selenium(IV) does not interfere.     

Precise coulometric determination of iron in iron ores with electrogenerated manganese(III) fluoride

Iron in Mohr's salt, electrolytic iron and iron ores has been determined by precision coulometric titration with electrolytically generated manganese (III) fluoride, with biamperometric end-point detection. The titration curve indicated the irreversibility of the electrode reaction of manganese(III) fluoride. Total iron in several standard samples of iron ores was determined with standard deviations of about 0.012%.     

Catalytic method for determination of micro amounts of gold in iron ores

Summary Gold in iron ores has been determined by means of its catalytic action on the oxidation of mercury(I) by cerium(IV). The calibration curve is linear over the range 3–30 ng/ml. Only iridium(IV), platinum(IV), palladium(II), ruthenium(III) and gallium(III) interfere seriously, though some interference is experienced from lead(II), iron(III), osmium(VIII) and indium(III).

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Zusammenfassung Gold wurde in Eisenerzen auf Grund seiner katalytischen Wirkung auf die Oxydation von Quecksilber(II) durch Cer(IV) bestimmt. Die Eichkurve verläuft von 2 bis 30 ng/ml linear. Nur Iridium(IV), Platin(IV), Palladium(II), Ruthenium(III) und Gallium(III) stören ernstlich, während eine geringfügige Störung auch durch Blei(II), Eisen(III), Osmium(VIII) und Indium(III) beobachtet wurde.

     

The photometric titration of nickel in the presence of cobalt

A spectrophotometric titration of nickel in the presence of cobalt is described using disodium ethylene diaminc tetraacetic acid as a titrant The end-point was obtained by plotting the corrected absorbancy against ml of titrant added Nickel concentrations of 2.5 to 25 mg were determined in the presence of up to 8 mg of cobalt with an error of 1$\text{1}\text{2}$% or less depending upon the concentration of Versenate used A 0.03M and 0.1M versenate was used The effects of pH, concentrations of nickel And cobalt, accuracy of the method, presence of interfering elements, and limitations of the method are discussed.     

The photometric titration of mercury with trien

A mercury(II) solution containing copper ion can be titrated photometrically at pH 4.7 with triethylenetetramine solution (trien) after the addition of iminodiacetic acid (IDA) ; IDA causes a reversal of the effective formation constants of Hg-trien and Cu-trien and permits the titration. Copper-trien which absorbs at 580 mμ serves as the indicator for the titration. Mercury can be determined in presence of many other metals with an accuracy of about 1%; the main interferences are iron-(III), nickel, bismuth and chloride ion.     

Unified automated determination of silicon in iron ores, sinters, slags, iron and steel

An automatic absorptiometric method is presented for the determination of silicon in iron ores, sinters, slags, iron and steel. The last two are dissolved in dilute sulphuric acid; the others are fused with sodium peroxide, then dissolved in hydrochloric acid. After suitable additions and dilution, the resulting solutions are treated identically in a Technicon AutoAnalyzer. The silicomolybdate formed is reduced to molybdenum blue with iron(II). Fluoride is added to provide a redox buffering system. The novelty of the method lies in selecting the sample sizes, conditions of fusion and/or dissolution and dilutions so that this universality is attained. Thus a single programme for the analyzer serves to determine, in any sequence, silicon in iron ores or sinters (1-6%), slags (3-10%), iron (0.4-2.5%) or steel (0.005-2%), the only change being in the tables used to translate transmittanee into per cent silicon. Both the precision and accuracy are satisfactory.     

Universal technique for rapid dissolution of materials encountered in the steel industry and its applications in the photometric determination of arsenic, phosphorus, titanium and vanadium in iron ores

A rapid, simple and virtually universal technique is described for decomposing a wide range of materials such as ores, sinters, slags, ferro-alloys and other reagents and additives used in the steel industry, as well as environmental dusts and particulate matter. The procedure involves fusion with sodium peroxide, alone or with sodium carbonate (mixed flux) in a zirconium or vitreous carbon crucible. Treatment of the fused melt with water and acid results in complete dissolution. It avoids the tedious operations involved in dissolving residues left by other dissolution techniques. Losses of normally volatile elements such as arsenic, phosphorus, lead and zinc do not occur. Application of this technique is described, particularly for the photometric methods developed for determining arsenic, phosphorus, titanium and vanadium in iron ores in the ranges 0.0002-0.1% As, 0.002-0.6% P, 0.01-0.6% Ti, and 0.001-0.5% V. Both the precision and accuracy are excellent.