N. M. Yakimova

Isotopic separation of lithium ions by capillary zone electrophoresis.

Separation of 6Li and 7Li isotopes by CZE was demonstrated. The BGE contained 5 mM 4‐aminopyridine, 0.9 mM oxalic acid, 0.25 mM CTAB, and 0.25% w/v Tween 20 (рН = 9.2). The running conditions were +25 kV at 30°C with indirect photometric detection at 261 nm. Under optimal experimental conditions, the analysis time was less than 21 min. Separation of Li preparations with mole fraction of 6Li ranging from 3.44 up to 90.38% was demonstrated.

Capillary-electrophoretic determination of zinc and cadmium ions in aqueous solutions with ion-exchange preconcentration

An approach to choosing analyte preconcentration conditions for the subsequent capillary electrophoresis (CE) analysis of the concentrate was substantiated using the simultaneous determination of zinc(II) and cadmium(II) trace concentrations as an example. A CE procedure was developed for the determination of Zn and Cd with the following characteristics: The time of the analysis, including analyte preconcentration from a 50-mL sample, was 30 min. The analytical ranges were 0.01–0.2 mg/L for cadmium(II) and 0.005–0.1 mg/L for zinc(II).

Fast isotopic separation of (10) B and (11) B boric acid by capillary zone electrophoresis.

Fast isotopic separation of 10B and 11B boric acid by CZE was demonstrated. The BGE contained 25 mM phenylalanine and 5 mM putrescine (рН 8.95). The running conditions were +25 kV at 20°C with indirect photometric detection at 210 nm. Baseline separation was achieved in less than 9 min. RSD of migration times and corrected peak areas were less than 0.5 and 3%, respectively (n = 5). Linearity was demonstrated in the range 0.2–2 mM for 11B and 0.2–0.5 mM for 10B.

Determination of alkylamines in aqueous media by capillary electrophoresis

A procedure is developed for the determination of organic amines in potable water and wastewater by capillary electrophoresis. A mixed solution of benzimidazole and tartaric acid is selected as a leading electrolyte for indirect photometric detection. The sample was injected hydrodynamically. The procedure was tested on samples of potable water and wastewater. The accuracy of the results was evaluated by the standard addition method. The analytical range is 0.25–5 mg/L. The analysis time is 4–5 min.

Determination of chloride and sulfate ions in high-purity water by capillary electrophoresis

A method is developed for the determination of chloride and sulfate ions in trace concentrations in high-purity water by capillary electrophoresis. A leading electrolyte based on chromate ions is used for indirect photometric determination. Electrokinetic sample injection is utilized. The internal standard method is used to improve reproducibility, and the conditions of sample injection with field amplification using an aqueous plug are optimized. The method is validated on samples of distilled, twice-distilled, and deionized water. The accuracy of the results of analysis was verified by the added-found method. The analytical range for chloride and sulfate ions is 1–50 μg/L; the detection limit is 0.3 μg/L. The duration of one analysis is 4–5 min.

Determination of trace amounts of Pd(II), Pt(IV), and Ir(IV) chlorocomplexes by capillary electrophoresis with extraction-chromatographic preconcentration

A comprehensive system is developed for the capillary-electrophoretic determination of trace amounts of Pd(II), Pt(IV), and Ir(IV) chlorocomplexes in sulfate-chloride solutions with their extraction-chromatographic preconcentration.

Determination of zinc(II) and cadmium(II) as their complexes with Xylenol Orange by capillary elecrophoresis using online preconcentration

A new version of online preconcentration employing the pH-stacking mechanism has been proposed; it has been implemented by the example of a procedure for the capillary electrophoretic determination of trace zinc(II) and cadmium(II) with photometric detection in the visible spectrum region as complexes with Xylenol Orange. The analytical range is 2–400 μg/L for zinc(II) and 1–500 μg/L for cadmium(II).

Determination of alkyl- and alkanolamines in drinking and natural waters by capillary electrophoresis with isotachophoretic on-line preconcentration

A procedure is developed for the determination of several amines in drinking and natural waters by capillary electrophoresis with isotachophoretic on-line preconcentration without sample preparation. A background electrolyte based on acridine as an absorbing ion is proposed for analysis with isotachophoretic on-line preconcentration and indirect photometric detection. The sample was injected in the hydrodynamic mode. The procedure was tested on drinking and natural water samples. The accuracy of data obtained was confirmed by the added–found method. The analytical range was from 0.25 to 5 mg/L. The time of one analysis was 5–6 min.