Advanced Stopped-in-Loop Flow Analysis with a Reagents-Merging Zones Technique for a Catalytic Successive Determination of Vanadium and Iron.

An advanced stopped-in-loop flow analysis (SILFA) is proposed for the catalytic determinations of vanadium and iron. The chemistry relies on a vanadium- or iron-catalyzed oxidative reaction of p-anisidine by bromate or hydrogen peroxide in the presence of an activator (Tiron or 1,10-phenanthlorine) to form a red dye (510 nm). Reagents for the vanadium- or iron-catalyzed reaction are well mixed by a reagents-merging zones technique.

Stopped-in-loop flow analysis system for successive determination of trace vanadium and iron in drinking water using their catalytic reactions.

An automated stopped-in-loop flow analysis (SILFA) system is proposed for the successive catalytic determination of vanadium and iron. The determination of vanadium was based on the p-anisidine oxidation by potassium bromate in the presence of Tiron as an activator to form a reddish dye, which has an absorption maximum at 510 nm. The selectivity of the vanadium determination was greatly improved by adding diphosphate as a masking agent of iron.

Automatic On-line Solid-phase Extraction-Electrothermal Atomic Absorption Spectrometry Exploiting Sequential Injection Analysis for Trace Vanadium, Cadmium and Lead Determination in Human Urine Samples.

A fully automated sequential injection column preconcentration method for the on-line determination of trace vanadium, cadmium and lead in urine samples was successfully developed, utilizing electrothermal atomic absorption spectrometry (ETAAS). Polyamino-polycarboxylic acid chelating resin (Nobias chelate PA-1) packed into a handmade minicolumn was used as a sorbent material. Effective on-line retention of chelate complexes of analytes was achieved at pH 6.