Katsuhiko Satoh

Determination of rare earths in lanthanum oxide by inductively-coupled plasma emission derivative spectrometry

Rare-earth elements (REE) at ppm levels in lanthanum oxide can be determined without prior separation and preconcentration by use of high-resolution inductively-coupled plasma emission derivative spectrometry (ICPEDS). The calibration graphs are all linear and pass through the origin, even in the presence of large amounts of lanthanum, except those for dysprosium, holmium and ytterbium. The detection limit for each REE is 1-10 mug g in lanthanum oxide. Investigation of various physical and/or spectral interferences shows that good selectivity is obtained by ICPEDS.

Spectrophotometric determination of manganese utilizing metal ion substitution in the cadmium-α,β,-γ,δ -tetrakis(4-carboxyphenyl)porphine complex

Abstract Manganese(II) reacts quickly with α, β, γ, δ-tetrakis(4-carboxyphenyl)porphine [T(4-CP)P] at room temperature by metal substitution with a cadmium—T(4-CP)P complex in weakly alkaline medium containing imidazole. Oxidation by dissolved oxygen gives a manganese(III) complex having the Soret band at 469 nm. This forms the basis of a spectrophotometric method for the determination of manganese in the range 25–560 μg l -1 . The sensitivity (0.001 absorbance) is 0.56 ng cm -2 . Interferences of 17 cations and 8 anions were examined; only Cu 2+ , Co 2+ , Cr 3+ and Pb 2+ interfered markedly. The method was successfully applied to the determination of manganese in tea leaves.

Development of a high-resolution inductively-coupled argon plasma apparatus for derivative spectrometry and its application to the determination of hafnium in high-purity zirconium oxide

A high-resolution apparatus for inductively-coupled plasma emission spectrometry (ICPES) has been developed, based on an echelle spectrometer modified for wavelength modulation with a quartz refractor plate. The selectivity of the technique is thus improved, and small amounts of hafnium in high-purity zirconium oxide can be determined directly without prior separation or preconcentration. A straight-line calibration curve passing through the origin is obtained without any correction for the interference from zirconium which exists in large excess. The detection limit for hafnium is 0.06 microg/ml, and the relative standard deviation (10 replicates) for hafnium at the 1.2 microg/ml level is about 3%.

Determination of Micro Amounts of Samarium and Europium by Analogue Derivative Spectrophotometry

ZusammenfassungDie Derivativspektrophotometrie mit analoger Differentialschaltung wurde auf die Samarium- und Europiumbestimmung im ppm-Bereich angewendet. Durch Messung der zweiten oder vierten Derivativspektren der charakteristischen Absorptionsbanden beider Ionen bei 400 nm können diese direkt und selektiv neben großen Mengen der meisten anderen Seltenen Erden ohne vorhergehende Trennung bestimmt werden. Durch Wahl geeigneter Meßbedingungen ist auch eine Bestimmung nebeneinander möglich. Das Prinzip der analogen Derivativspektrophotometrie wird beschrieben.SummaryDerivative spectrophotometry using the analogue differentiation circuit was applied to the determination of samarium and europium at ppm levels. By measuring the second or the fourth derivative spectra of the characteristic absorption bands of both the rare earth ions around 400 nm, they can be determined directly and selectively in the presence of large amounts of most other rare earths without any prior separation. Further, aptly selecting conditions for the measurement of the derivative spectra, the simultaneous determination of both the rare earth elements was feasible. The principle and the characteristics of analogue derivative spectrophotometry are also described.

Spectrophotometric and analogue derivative spectrophotometric determination of ultramicro amounts of cadmium with cationic porphyrins.

alpha,beta,gamma,delta-Tetrakis(1-methylpyridinium-3-yl)porphine [T(3-MPy)P] and alpha,beta,gamma,delta-tetrakis(1-methylpyridinium-4-yl)porphine [T(4-MPy)P] have been found to react rapidly with cadmium to give coloured complexes in weakly alkaline media at room temperature. Simple and practical methods for the determination of cadmium at ng/ml levels by conventional and analogue derivative spectrophotometry have been proposed. The analogue method gives higher sensitivity. T(3-MPy)P gives higher sensitivity than T(4-MPy)P. The interference of various foreign cations and anions has also been examined and in many cases eliminated or reduced. Adsorption of the porphyrins and their cadmium complexes onto the glassware, which is usually observed under the conditions of reaction and causes significant errors in the determination, can be suppressed almost completely by addition of fairly large amounts of a salt such as sodium chloride.

Spectrophotometric determination of ultramicro amounts of zinc with α,β,γ,δ-tetrakis-(1-methylpyridinium-3-yl)porphine

A sensitive and practical method for the determination of zinc at parts per 109 levels with α,β,γ,δ-tetrakis(1-methylpyridinium-3-yl)porphine [T(3-MPy)P or H2L4+] has been developed. Zinc(II) reacts rapidly with T(3-MPy)P to form a 1:1 complex at pH 10.5, the T(3-MPy)P remaining is converted into its copper(II) complex by adding a small excess of copper(II) at this pH after the zinc(II) complex has been formed, the zinc(II) complex is decomposed by acidifying the solution and the absorbance of the Soret band of the resultant H4L6+ equivalent to zinc is measured. The spectrophotometric sensitivity for 0.001 absorbance and the relative standard deviation of the procedure are 0.186 ng cm–2 and 0.48%, respectively. Adsorption of T(3-MPy)P and its complexes on the walls of glassware in alkaline media did not interfere with the determination because the absorbance measurement was carried out in an acidic medium. Interferences from cations were removed by the combined use of masking agents and solvent extraction with dithizone. Anions usually encountered did not interfere with the determination. The proposed procedure has been applied to the determination of zinc in tap water.