A. P. Joshi

Photometric determination of gallium, indium, and thallium employing Solochrome Cyanine R

Abstract The formation of violet color between SCR and Ga(III), In(III), and Tl(III) have been studied. The analytical data for the spectrophotometric determination of these metals with SCR have been calculated. Range for adherence to Beers law, sensitivity, and the values of molecular extinction coefficient, suggest SCR as a sensitive reagent for the spectrophotomctric determination of Ga(III), In(III) and Tl(III).

Extraction and spectrophotometric determination of copper with 1-phenyl-3-thiobenzoyl thiocarbamide

Summary1-Phenyl-3-thiobenzoyl thiocarbamide (PTT) is used for the extraction and spectrophotometric determination of copper at trace level. The yellow coloured Cu-PTT complex is extracted in chloroform, showsλmax at 360 nm and is stable for 8 days. Beers law is followed in the range of 0.04 to 0.36μg of copper per ml. The effect of the presence of various ions is studied. Copper in alloys has been determined using this method.ZusammenfassungPTT wurde für die Extraktion und spektrophotometrische Bestimmung von Kupfer-Spuren verwendet. Der gelbe Cu-PTT-Komplex wird mit Chloroform extrahiert und ist für 8 Tage beständig.λmax liegt bei 360 nm. Das Beersche Gesetz gilt zwischen 0,04 und 0,36μg Cu/ml. Der Einfluß verschiedener Fremdionen wurde untersucht. Mit Hilfe der angegebenen Methoden wurde der Kupfergehalt in Legierungen bestimmt.

Extraction and spectrophotometric determination of platinum(IV) using tetramethylthiuram disulfide

Abstract The extraction and photometric determination of platinum(IV) with tetramethylthiuram disulphide has been studied. Addition of an excess of stannous chloride and maintaining acidity to 2–6 M with HCl is necessary for quantitative extraction. With 10 ml of TMTD in toluene and equilibration for 30 sec, platinum is extracted as a pale yellow complex in the organic phase. It has λ max at 348 nm and obeys Beers law in the concentration range of 0.2 to 9.0 μg of Pt per ml. The complex is stable for 3 hr. The ratio of Pt:TMTD in the extracted species is found to be 1:1. Most of the anions and cations are tolerated in large ratio. The method can be satisfactorily applied for the determination of platinum in the presence of four- and eightfold excesses of ruthenium and osmium, respectively.

Extraction and Spectrophotometric Determination of Osmium by Tetramethylthiuram Disulphide in Toluene

SummaryTetramethylthiuram disulphide (TMTD) is used for the extraction and spectrophotometric determination ofμg quantities of osmium. 15 ml of 1.052×10−3 M TMTD in toluene quantitatively extracts osmium from7 M HCl. The complex attains maximum colour intensity in 2 hours. It is red in colour and exhibits two λ max. One at 445 nm and the other at 504 nm. The maximum at 504 nm is more significant. Beers law was found to hold good over the concentration range of 1.7 to 26.7μg of osmium per ml. The Ringbom plot shows the optimum range of 9.42 to 23.65μg of osmium per ml. The optimum period of equilibration is 30 seconds and the complex is stable up to 5 hours. The extracted species shows the composition to be 1 ∶ 1 (Os ∶ TMTD). It is possible to extract and determine osmium in the presence of other platinum metals with composition corresponding to the ore osmiridium.ZusammenfassungTetramethylthiuramdisulfid (TMTD) wurde zur Extraktion und spektrophotometrischen Bestimmung von Mikrogrammengen Osmium verwendet. 15 ml einer 1,052.10−3-molaren Lösung von TMTD in Toluol dienen zur Extraktion von Os aus 7-m Salzsäure. Der entstandene rote Komplex erreicht innerhalb 2 Stunden maximale Farbintensität und zeigt zwei Absorptionsmaxima bei 445 nm und 504 nm. Letzteres ist signifikanter. Zwischen 1,7 und 26,7μg Os/ml gilt das Beersche Gesetz. Nach der Ringbom-Gleichung liegt die geeignetste Konzentration zwischen 9,42 und 23,65μg Os/ml. Nach 30 sec stellt sich das Gleichgewicht ein und bleibt bis zu 5 Stunden konstant. Die extrahierte Substanz entspricht der Zusammensetzung 1 ∶ 1 (Os ∶ TMTD). Os läßt sich auch in Gegenwart anderer Platinmetalle so extrahieren und bestimmen.

A study of the chelation reaction of gallium and indium with Arsenazo 1

Abstract The chelation reactions of gallium and indium with Arsenazo 1, i.e., 3-[( o -arsonophenyl)azo]-4,5-dihydroxy-2,7-naphthalene disulfonic acid, have been studied in detail. The nature and number of complexes formed was studied and it was found that gallium and indium form only one complex with Arsenazo 1. The composition of the complexes formed was found by various methods and it was found that both the complexes have composition 1:1 (metal:reagent). The values of log K were calculated by different methods at four different fixed values of ionic strength. For both the complexes, the value of thermodynamic stability constant has been obtained by plotting values of log K against ionic strength and extrapolating the curves to zero ionic strength. A tentative suggestion about the structure of the chelate ring has been made. The studies were further extended to the analytical aspects of the complexes and a suitable procedure has been recommended for the spectrophotometric determination of gallium and indium using this reagent.

Spectrophotometric determination of indium using gallion

SummaryThe formation of violet coloured chelate of indium with Gallion has been studied. Indium forms only one chelate with Gallion at pH 4.5 havingλmax 610 nm. The composition of the complex formed has been determined by various methods and is found to be 1∶1 (M∶R). The values of stability constant have been calculated by three methods and the average value of logK obtained is 5.6 ± 0.1. A procedure for the spectrophotometric determination of indium has been suggested.ZusammenfassungDie Bildung eines violetten Chelates von Indium mit dem Reagens „Gallion“ wurde studiert. In bildet damit ein einziges Chelat bei pH=4,5 undλmax=610 nm. Die Zusammensetzung des entstandenen Komplexes wurde nach verschiedenen Methoden ermittelt und gleich 1∶1 (Metall∶Reagens) gefunden. Die Stabilitätskonstante wurde nach drei Verfahren berechnet, wobei sich als Mittelwert logK=5,6±0,1 ergab. Eine Arbeitsvorschrift für die spektrophotometrische Bestimmung des In wird vorgeschlagen.

1-Phenyl-3-thiobenzoyl thiocarbamide as a sensitive reagent for the determination of iron

SummaryA highly sensitive reagent, 1-phenyl-3-thiobenzoyl thiocarbamide (PTT) is used for the extraction and spectrophotometric determination of iron at trace level. The yellowish-red coloured Fe-PTT complex is formed at room temperature and maximum colour intensity is attained in 60 min. It is extractable into chloroform and shows maximum absorption at 410 nm. Beers law is followed in the range of 2–20 ng Fe/ml. The sensitivity of determination (Sandells) is 0.0266 ng/cm2 and molar absorptivity is 2.094×106l·mol−1·cm−1. Many common ions are tolerated to a large ratio. The method has been utilized to determine iron in drugs, water and ores.ZusammenfassungEin hochempfindliches Reagens, 1-Phenyl-3-thiobenzoylthiocarbamid (PTT), wurde für die Extraktion und spektrophotometrische Bestimmung von Eisenspuren verwendet. Der gelb-rot gefärbte Fe-PTT-Komplex bildet sich bei Zimmertemperatur und erreicht sein Farbmaximum innerhalb 60 min. Er läßt sich mit Chloroform extrahieren und hat ein Absorptionsmaximum bei 410 nm. Im Bereich 2–20 ng Fe/ml ist das Beersche Gesetz erfüllt. Die Empfindlichkeit der Bestimmung beträgt 0,0266 ng/cm2, die molare Absorption 2,094·106l·mol−1·cm−1. Viele Ionen stören auch in großer Menge nicht. Das Verfahren wurde zur Eisenbestimmung in Drogen, in Wasser und in Erzen verwendet.