Chelatometric Titration Research Articles

Chelatometric Titration of Cobalt and Nickel with Gallein as Indicator

AbstractIn continuation of a series of chelatometric titration of metal ion with gallein indicator, two procedures for the EDTA titration of cobalt and nickel using gallein as indicator were proposed. In one procedure cobalt ion was titrated with standard 0.05 M EDTA solution in ammonium chloride buffer by stepwise addition of ammonia to keep the pH at the optimum value of 8. A sharp color change from violet to rose red indicating the end point can be observed. In another procedure nickel ion was titrated with standard 0.05 M EDTA solution at pH 8 to 9 in ammonia‐ammonium chloride buffer solution. The end point is indicated by a color change from bluish violet to rose red.The interference caused by the presence of approximately equal molar concentration of various foreign ions was observed.

Chelatometric Titration of Cadmium with Gallein Indicator

AbstractIt has been found that gallein can be used as an indicator in the direct chelatometric titration of a number of metals. A method based on this fact has been devised for the chelatometric determination of cadmium with disodium salt of EDTA.The optimum pH for the titration was found to be 9.5 to 10. A buffer solution consisting of ammonia and ammonium chloride was used to keep the solution at this optimum pH in the titration. The color of indicator changed from violet to magenta red at the end point.No interference was observed in the presence of a variety of anions and univalent cations.

Determination of Lead in Leaded Free Cutting Steels by the Chelatometric Titration Method

A simple chelatometric titration method for the determination of Lead in Leaded free cutting steel has been developed. The samples are dissolved in HCl, HNO3 and HClO4 and Iron (III) is extracted into Methyl Isobutyl Ketone from 6 N HCl solution. Chromium (VI), Molybdenum (VI), Vanadium (V), are also extracted. In the aqueous solution, Aluminum, Copper, Nickel, Cobalt and Manganese ions are masked with Triethanolamine and Potassium Cyanide. Lead is titrated at pH 10 to pH 11 using Thymolphthalein complexone as an indicator. The proposed has the advantage of speed, yet has the same accuracy as the classical gravimetric method.

Determination of tin in iron and steel by chelatometric titration method

鉄鋼試料を硝酸と過塩素酸で分解して白煙処理をしたのち,ケイ素その他をロ過して分離する.ロ液にEDTAおよび硫酸ベリリウム溶液を加え,アンモニア水で弱アルカリ性とし,ベリリウムとともにスズを水酸化物として沈殿させ,鉄その他から分離する.これをロ過しEDTAを加えた希アンモニア水で洗浄する.沈殿を硫酸に溶解し,塩素酸カリウムを加えて加熱蒸発し,沈殿に付随してきたEDTAを分解駆除する.これにアスコルビン酸および過剰のEDTA標準液を加えたのち,酢酸アンモニウム溶液を加えpHを2~3に調節する.キシレノールオレンジを指示薬として加え,トリウム標準液で過剰のEDTAを逆滴定し,スズ量を算出する.この方法により,従来の容量法あるいは吸光光度法では定量困難な高合金鋼中のスズを定量し,良好な成績が得られた.

EDTA滴定法による鉛快削鋼中の鉛の定量

EDTA滴定法による鉛快削鋼中の鉛の定量

Calcein blue—a new metalfluorechromic indicator for chelatometric titrations

A new metal fluorechromic indicator is described for the chelatometric titration of metal ions. Calcein Blue (a condensation product of 4-methylumbelliferone, formaldehyde, and iminodiacetic acid) may be used for the chelatometric determination of metal ions which form highly coloured complexes with chelatometric reagents. A procedure based on reaction rates is given for the determination of nickel and chromium in mixtures without prior separations. Calcein Blue serves as an indicator for the direct titration of the alkaline earth elements as the result of the formation of an indicator-reversal complex.

Determination of metal ions in solution by means of taa and edtaGeneral introduction and determination of zinc

Summary The behaviour of metal ions with EDTA and TAA in acid and alkaline solutions is discussed and a specific quantitative determination of zinc is described. The use of TAA instead of hydrogen sulfide provides a much better separation of zinc from the elements of group II. After addition of EDTA and ammonia, iron, aluminium and manganese are precipitated in the filtrate as hydroxides by addition of calcium chloride. Zinc is then precipitated as the sulfide with TAA, while nickel and chromium remain in solution. After the precipitate has been dissolved zinc is determined by chelatometric titration with EDTA. As little as 0.6 mg of zinc can be determined in presence of a large excess of other group II and group III elements.

Hematoxylin as indicator in the chelatometric titration of metals

Hematoxylin as indicator in the chelatometric titration of metals

Hematoxylin as indicator in the chelatometric titration of metals

Hematoxylin is suggested as an indicator in the titration of several metals with EDTA. Bismuth and zirconium were readily determined in acidic medium. Several other metals also gave color reactions, but the color changes on addition of EDTA were not sharp. L'auteur a étudié le comportement de l'hématoxiline, comme indicateur, lors du dosage de divers métaux, au moyen de l'EDTA. Les résultats obtenus lors du titrage du bismuth et du zirconium sont satisfaisants. Es wurde Hämatoxylin auf seine Eignung als Indikator bei der Titration von Metallen mit EDTA untersucht. Gute Werte werden bei der Titration von Bismut und Zirkonium erhalten.