Jerzy Ciba

Studies on spectrophotometric methods of thallium determination

Eight sensitive methods of spectrophotometric determination of thallium have been studied and compared experimentally. The comparative criteria were: molar absorptivity, colour contrast of the basic reaction, working concentration interval and practical determination limit for thallium, precision of the method (the standard deviation), and selectivity. According to these criteria the best methods of extraction-spectrophotometric determination of thallium are those using Brilliant Green, Crystal Violet, Methyl Violet and Rhodamine B. The sensitivity depends very much on the oxidant used for conversion of Tl(I) into Tl(III). The oxidants suitable for each of the recommended methods are discussed.

Spectrophotometric determination of boron in human hair with azomethine H

SummaryInvestigation of methods of hair sample mineralization was made. The most profitable method of hair mineralization was by combustion in oxygen. Boron was determined spectrophotometrically with azomethine H as a spectrophotometric reagent. Boron in hair was determined in the range of 0–5 μg/g.

Determination of lanthanum, cerium, praseodymium and neodymium in alloy steels by inductively coupled plasma atomic-emission spectrometry.

Inductively coupled plasma spectrometry has been applied to the determination of La, Ce, Pr and Nd in alloy steels. Spectral interference by other alloying elements as well as by the lanthanides themselves was studied. The influence of other lanthanides on the Pr and Nd lines could be dealt with by correction equations. It was found that within the range of concentrations corresponding to mild alloy steel, at least one of the lines selected for determining the lanthanides was free from interferences. The detection limits for La, Ce, Pr and Nd in steel were 5 x 10(-5), 1.5 x 10(-4), 1 x 10(-4) and 2.4 x 10(-4)% respectively. The procedure was tested on standard samples and by the standard-addition method.

Use of blotting-paper collectors for the separation and X-ray fluorescent determination of traces of heavy metals (Cu, Hg, Ag) in water and waste water

ZusammenfassungHg, Ag und Cu im Bereich von 0,5–500 Μg wurden auf Flie\papier-Kollektoren abgetrennt und direkt durch energiedispersive Röntgenfluorescenzanalyse bestimmt. Die Ergebnisse wurden durch Spektralphotometrie überprüft. Die Kollektoren enthielten 0,2 mM ZnS, für Ag statt dessen auch Thioureid. Alle Ergebnisse waren in guter übereinstimmung. Die Nachweisgrenzen für den ZnS-Kollektor betrugen 0,2 Μg Hg, 0,4 Μg Cu, 0,15 Μg Ag; für den Thioureid-Kollektor 0,13 Μg Ag.SummaryTraces of Hg, Ag and Cu were separated in the range of 0.5–500 Μg with blotting-paper collectors and were subsequently determined directly with energy dispersive X-ray fluorescence. For comparison, spectrophotometric determinations were carried out as well. The results were in good agreement. The collectors contained 0.2 mM ZnS, in case of Ag a thioureide collector was also employed. Limits of detection were 0.2 Μg Hg, 0.4 Μg Cu and 0.15 Μg Ag for the ZnS collector and 0.13 Μg Ag for the thioureide collector.

Spectrophotometric determination of La, Ce, Pr and Nd in the presence of copper by use of arsenazo III

SummaryArsenazo III was applied to the determination of the total amount of La, Ce, Pr and Nd in the presence of Cu, using sodium thiosulphate for masking Cu up to 50 mg. The lanthanides can be analyzed within the range of 0–2.4 or in presence of Pb, Al, Ni, Fe 0–1.6 mg/l. Interferences of Zn, Mn, Ni, Al, Sn, Pb and Fe were examined. The procedure was applied to the determination of Ce in CuSnCe alloys and Al and Pb brasses without prior separation of the matrix.

Determination of boron in copper and copper-, nickel- and cobalt-base alloys

ZusammenfassungZur Extraktion von Bor aus diesen Proben wurde ein pyrohydrolytisches Verfahren ausgearbeitet. Die Borbestimmung erfolgt bei Gehalten >0,1% B alkalimetrisch in Gegenwart von Mannit und Phenolphthalein oder potentiometrisch, bei Gehalten <0,1% B durch Spektralphotometrie mit Azomethin H. Die Standardabweichungen liegen im Bereich von 0,008–0,15% B.SummaryA pyrohydrolytic method for the extraction of boron from coppper and copper-, nickel- and cobalt-base alloys has been developed. For concentrations higher than 0.1 %, boron is determined by an alkalimetric method in the presence of mannitol and phenolphthalein or by a potentiometric method. For samples containing less than 0.1% of boron, it is determined by spectrophotometry with azomethine H. Standard deviations are in the range of 0.008 to 0.15% B.

Indirekte polarographische Bestimmung der o-Phthalsure neben ihren Estern

SummaryAn indirect polarographic method is proposed for the determination of phthalic acid in presence of its esters. Lead(II) phthalate is precipitated from an alcoholic phthalic acid solution, is filtered off, and is dissolved in ammonium acetate solution. The polarographic wave is measured at galvanometer sensitivity 1/70, a potential of -0.6 V and pH 5.6. The maximum error is 5%.ZusammenfassungEine indirekte polarographische Methode zur Bestimmung von Phthalsäure in Gegenwart ihrer Ester wird vorgeschlagen. Hierbei wird Blei(II)-phthalat aus einer alkoholischen Lösung der Phthalsäure abgeschieden, abfiltriert und in Ammoniumacetatlösung gelöst. Die polarographische Stufe wird bei Galvonometerempfindlichkeit 1/70, Potential -0,6 V und pH 5,6 gemessen. Der Fehler beträgt maximal 5%.

Beitrag zur Yttriumbestimmung in Stahl und Chrom/Nickel-Legierungen mit Wellendispersiver Röntgenfluorescenz — Abtrennung der Matrix

SummaryFor the XFA determination of yttrium in steels and Cr/Ni-alloys two procedures for matrix separation are described. For steels an ion-exchange procedure is used, whereas for Cr/Ni-alloys extraction with CHCl3/C6H6 is preferred. In the latter case separation of interfering iodine is necessary. If the matrix contains high amounts of both Fe and Cr/Ni a combination of the two procedures is recommended. The range of determination is 0.001–0.1% Y.ZusammenfassungZur röntgenfluorescenzanalytischen Bestimmung von Yttrium in Stahl und Cr/Ni-Legierungen werden zwei Verfahren zur Abtrennung der Matrix beschrieben. Für Stahl wird ein Ionenaustauschverfahren benutzt, während für Cr/Ni-Legierungen Extraktion mit CHCl3/C6H6 empfohlen wird. Bei der Extraktion muß störendes Iod abgetrennt werden. Falls die Matrix hohe Mengen sowohl von Fe als auch Cr/Ni enthält, können beide Verfahren kombiniert werden. Der Bestimmungsbereich beträgt 0,001–0,1% Y.

Bestimmungsmethoden für Milligrammengen Sebacinsäure

SummaryThe quantitative precipitation of sebacic acid with lead(II) ions has been employed for a gravimetric method of determination and also for an indirect polarographic (in ammonium acetate solution) and spectrophotometric one (using dithizone extraction). Concentration ranges are 20–200 mg, 2–15 mg, and 0,5 to 2 mg, respectively.ZusammenfassungAuf Grund der quantitativen Fällung von Sebacinsäure mit Blei(II)ionen wurden die direkte gravimetrische Bestimmung sowie Methoden zur indirekten Bestimmung der Sebacinsäure entwickelt. Je nach dem Gehalt der Probe werden je eine polarographische in Ammoniumacetatlösung und eine spektralphotometrische Methode nach Dithizonextraktion empfohlen.