Determination of trace metals by capillary electrophoresis

Abstract

A new analytical procedure is developed using a strong complexing agent, 1,10-phenanthroline (Phen), for direct UV detection of Zn, Mn, Cu, Co, Cd, and Fe at microg/L concentrations in environmental water samples. The metal chelates formed showed different electrophoretic mobilities and solved the comigration problem for capillary electrophoresis (CE) separation of free metal ions. To obtain stable metal-Phen chelates during the capillary zone electrophoresis (CZE) run, both pre-column and on-column complexation are required and threefold excess of Phen over metal ions should be added to the sample. The optimized background electrolyte (BGE) consists of 30 mM hydroxylamine hydrochloride and 0.1% methanol at pH 3.6. Under hydrodynamic sampling, CE run at + 20 kV in 65 cm x 0.05 mm ID fused-silica column with detection at 265 nm, baseline separation, satisfactory working ranges (10 microg/L to 5.5 mg/L), sensitive detection limits (1-3 microg/L), good repeatability for migration times (relative standard deviation, RSD 0.36-0.81%, n = 5), peak area (RSD 3.2-4.2%, n = 5) and peak height (RSD 3.2-4.5%, n = 5) were obtained for the metal cations investigated. The reliability of the method was established by parallel determination using the inductively coupled plasma-atomic emission spectrometry (ICP-AES) method giving results within statistical variation. The procedure developed is shown to provide a quick, sensitive, precise, and economic method for simultaneous determination of metal cations that can form stable chelates with Phen.

Use of carboxylic group functionalized magnetic nanoparticles for the preconcentration of metals in juice samples prior to the determination by capillary electrophoresis

“…To obtain stable metal‐phenanthroline chelates during the CE run, both precapillary and on‐capillary complexation are required and threefold excess of phenanthroline over metal ions is added to the sample. In the literature, among the varied electrophoretic methods to determine metals in CE a reoptimized electrophoretic method reported by other authors has been used in order to achieve better electrophoretic resolution between analytes.…”

Separation, Analysis and Validation of Metal Ions in Aqueous Samples Using Capillary Electrophoresis

“…-Hydroxyisobutyric acid-4-amino pyridine background electrolyte was chosen for the analysis of real samples since all 10 metals could be analysed. -Hydroxyisobutyric acid is a widely used complexing agent since it complexes with a large number of metal ions [6] and contains suitable binding groups (carboxyl, hydroxyl) [7].…”

Determination of lithium and transition metals in Li1Ni1/3Co1/3Mn1/3O2 (NCM) cathode material for lithium‐ion batteries by capillary electrophoresis

“…In contrast, CE was not applied in the field of LIBs so far, especially for elemental determination of electrode materials. The focus of CE has been mainly on environmental monitoring of tap, rain, and surface water ; residues of firework explosions ; and medicine research . Herein, we report for the first time the development of a feasible CE method for the determination of lithium and transition metals in NCM cathode samples after microwave digestion and the calculation of the active material stoichiometry.…”