Trace determination of perchlorate in drinking water by capillary zone electrophoresis with isotachophoresis sample cleanup and conductivity detection

Abstract

An analytical test procedure for the direct determination of trace levels of perchlorate in drinking water by isotachophoresis combined with capillary zone electrophoresis was developed. A capillary electrophoresis analyzer with column coupling technology, capable of combining capillaries with different internal diameters, was employed in combination with conductivity detection. This combination of the capillary electrophoresis techniques facilitated preconcentration of the trace analytes and elimination of potentially interfering macro-components. To eliminate the influence of weak and moderately strong acids on the migration of perchlorate, acidic leading electrolyte (pH 3.2) in the isotachophoresis step and acidic background electrolyte (pH 3.9) in the zone electrophoresis step were chosen. The addition of polyvinylpyrrolidone into the electrolytes enhanced the resolution of perchlorate from other anions, especially remaining anionic macro-components. The developed method is characterized by good repeatability of migration time (relative standard deviation less than 0.2%) as well as peak area (relative standard deviation less than 5.9%), linearity (R = 0.9996), recoveries (100-112%), and sample throughput (90 samples/24 h). The limit of quantitation for perchlorate in drinking water was achieved at 12.5 nmol/L (1.25 μg/L). This approach is more sensitive and more robust than transient isotachophoresis and offers advantages over some more established analytical techniques such as ion chromatography.

Capillary Electrophoresis: A Three-Year Literature Review

“…Similarly, a dynamic pH barrage junction stacking method was used for the quantification of sulfonamide, a synthetic broad-spectrum antibiotic in milk and yogurt . Zabensky et al applied a column coupling technique to combine two capillaries of different dimensions with separate detectors to establish a high-throughput method (90 samples per day) for the trace detection of perchlorate ions in drinking water . A CE-LIF-based assay was developed for the quantitative detection of free cyanide ions via the addition of nonfluorescent 3-(2-furoyl)­quinoline-2-carboxaldehyde reagents .…”

“…16 Zabensky et al applied a column coupling technique to combine two capillaries of different dimensions with separate detectors to establish a high-throughput method (90 samples per day) for the trace detection of perchlorate ions in drinking water. 248 A CE-LIF-based assay was developed for the quantitative detection of free cyanide ions via the addition of nonfluorescent 3-(2furoyl)quinoline-2-carboxaldehyde reagents. 249 This approach was used to determine cyanide ion concentration in apple seeds, confirming its potential in analyzing seeds and fruit pits which usually contain nitriles.…”

Sensitivity enhancement of capillary electrophoresis‐frontal analysis‐based method for characterization of drug‐protein interactions using on‐line sample preconcentration

“…Common on-line sample preconcentration strategies include field-amplified sample stacking (FASS) [20], fieldamplified sample injection, large-volume sample stacking, transient ITP (tITP), dynamic pH-junction [21,22], and sweeping. Recently even dual or multiple-focusing strategies have also been described [14,16,23,24]. These strategies can be divided into two groups according to the physical phenomena used to concentrate analytes.…”