Filtro de Aplicações

The simultaneous ion chromatographic determination of trace-levels of lanthanides (or lanthanoides) was achieved by using either direct non-suppressed conductivity detection or UV/VIS detection after post-column reaction (PCR) with arsenazo III at 655 nm. Conductivity detection under isocratic conditions resulted in an overall analysis time of approx. 70 minutes. In contrast, the determination of the lanthanides via gradient elution and subsequent spectrophotometric detection of the arsenazo III-lanthanide(III) complexes was performed within 22 minutes. Besides the outstanding analysis time, UV/VIS detection excelled by its enhanced selectivity and sensitivity and did not suffer from interferences by ubiquitous non-lanthanide impurities such as iron(III) or other transition metals. For both conductivity and spectrophotometric detection, the inclusion of sample preconcentration steps lowered the limit of detection (LOD) to the sub-ppb range.

A convenient adsorptive cathodic stripping voltammetric (AdCSV) method has been developed for trace determination of uranium(VI) in drinking water samples using chloranilic acid (CAA). The presence of various matrix components (KNO3, Cl-, Cu2+, organics) can impair the determination of the uranium-CAA complex. The interferences can be mitigated, however, by appropriate selection of the voltammetric parameters. While problematic water samples still allow uranium determination in the lower µg/L range, in slightly polluted tap water samples uranium can be determined down to the ng/L range, comparable to the determination by current ICP-MS methods.

In the following tables, the half-wave potentials or peak potentials of 90 metal ions are listed. The half-wave potentials (listed in volts) are measured at the dropping mercury electrode (DME) at 25 °C unless indicated otherwise.

Este documento descreve a determinação complexométrica e potenciométrica de íons metálicos por titulação com EDTA, utilizando um eletrodo íon-seletivo de cobre (Cu-ISE) com haste de epóxi durável e membrana de cristal. Como o eletrodo é insensível a agentes complexantes, um complexo pré-formado de Cu-metal deve ser introduzido na amostra antes da análise. O método, aplicável tanto à titulação direta quanto à retrotitulação, utiliza as constantes de formação EDTA-metal para definir os pontos de equivalência e permite a quantificação em diversas matrizes diferentes.

This Bulletin describes the fully automated determination of uranium according to the method of Davies and Gray: Uranium(VI) is reduced in concentrated phosphoric acid solution with iron(II) to form Uranium(IV). With molybdenum as a catalyst, the excess iron(II) is oxidized with nitric acid. The nitrous acid that is formed is destroyed with sulfamic acid before uranium(IV) is titrated with a potassium dichromate solution in the presence of a vanadium catalyst.

This Application Bulletin describes the determination of titanium by adsorptive stripping voltammetry (AdSV) using mandelic acid as complexing agent. The method is suitable for the analysis of ground, drinking, sea, surface and cooling waters, in which the concentration of titanium is of importance. The methods can, of course, also be used for the trace analysis in other matrices. The limit of detection is approx. 0.5 µg/L.

This Application Bulletin describes the methods for the determination of uranium by adsorptive stripping voltammetry (AdSV) according to DIN 38406 part 17. The method is suitable for the analysis of ground, drinking, sea, surface and cooling waters, in which the concentration of uranium is of importance. The methods can, of course, also be used for the trace analysis in other matrices. Uranium is determined as chloranilic acid complex. The limit of detection in samples with low chloride concentration is about 50 ng/L and in seawater about 1 µg/L. Matrices with high chloride content can only be analyzed after reduction of the chloride concentration by means of a sulfate-loaded ion exchanger.

Determination of traces of lutetium, ytterbium, thulium, erbium, terbium, gadolinium, samarium, neodymium, praseodymium, cerium, and lanthanum using cation chromatography with direct conductivity detection.

Determination of traces of gadolinium, samarium, neodymium, cerium, and lanthanum using cation chromatography with direct conductivity detection after Metrohm Inline Filtration.

Determination of traces of lutetium, ytterbium, thulium, erbium, terbium, gadolinium, samarium, neodymium, praseodymium, cerium, and lanthanum using cation chromatography with gradient elution and UV/VIS detection after post-column reaction with Arsenazo III.

Thorium is titrated with EDTA at a pH value of 4.9. Xylenol orange is used as the indicator for visualization of the equivalence point. The equivalence point is determined with the Optrode at a wavelength of 574 nm.

A pureza dos elementos de terras raras (REEs) pode ser determinada por titulação complexométrica absoluta com xylenol orange (ISO 23597). Essa abordagem alcança recuperação de aproximadamente 100%, elimina a necessidade de calibração e oferece maior exatidão e reprodutibilidade do que técnicas como AAS (espectroscopia de absorção atômica). A titulação fotométrica com o Optrode M2 oferece detecção de comprimento de onda ajustável, proporcionando uma alternativa rápida, precisa e de baixo custo em relação a outros métodos convencionais.

Os elementos de terras raras (REEs) são materiais críticos cuja viabilidade de exploração e cujos fluxos de processamento exigem a determinação precisa da fração mássica durante a dissolução e a purificação do minério. Esta Nota de Aplicação descreve uma retrotitulação potenciométrica rápida, utilizando um eletrodo íon-seletivo de cobre (Cu-ISE), que permite a quantificação seletiva e a separação parcial de REEs em matrizes complexas, com recuperação quase quantitativa. Por se tratar de um método absoluto, flexível e de baixo custo, com preparo de amostra compatível com ICP, a retrotitulação é adequada tanto como técnica de referência quanto para análises rápidas em campo.

Uranium can be determined in drinking water by adsorptive stripping voltammetry (AdSV) at the hanging mercury drop electrode (HMDE). Chloranilic acid is used as complexing agent.

This article describes the investigation using ion chromatography and subsequent inductively coupled plasma mass spectronomy (ICP/MS) to determine the extent to which the iron(III) flocculation carried out in the context of wastewater treatment releases toxic gadolinium(III) ions as the result of recomplexing.

The coupling of ion chromatography and inductively coupled plasma mass spectrometry (ICP/MS) leads to a high-performance measurement system that masters several particularly challenging analyses. It enables for example reliable determination of element compositions, oxidation states and chemical bonds. This information is used, for example, for assessing the toxicity of medications, environmental and water samples as well as foods and beverages.