Direct Analysis of Inorganic Anions in Samples with High Salt Content by Capillary Zone Electrophoresis

Abstract

Trace-level inorganic anions in seawater are separated efficiently by capillary zone electrophoresis using direct UV detection. The carrier electrolyte is 50 mM borate at pH 9.3 and contained 1.5M NaCl. This buffer solution is adopted to prevent interference from high concentrations of the chloride ion in seawater. No electro-osmotic flow reverser is used to shorten the analysis time. The experimental conditions such as the concentration of NaCl in the carrier electrolyte, capillary inner diameter, applied current, and temperature are optimized. Linear plots are obtained in the concentration range of 0.1 to 20 microg/mL. The quantitation limits of the anions are in the order of 0.02 to 0.1 microg/mL. The proposed method may be applicable to the determination of inorganic anions in other environmental samples and effluents of a power plant.

Mixture design of an electrolyte system for the simultaneous separation of Cl−, SO42−, NO3−, NO2−, and HCO3− in shrimp-farming water by CZE-UV

“…This is a benet of this work since other studies add salts, such as NaCl, in to BGE to overcome the high ionic strength of this type of sample or carry out preconcentration by eld-amplied sample stacking. 13,35,36…”

Submersible Capillary Electrophoresis Analyzer: A Proof-of-Concept Demonstration of an In Situ Instrument for Future Missions to Ocean Worlds

“…CE instrumentation is relatively compact, requires only small quantities of reagents and sample, and can be tailored for a wide range of potential analytes. In addition, CE is capable of analyzing the organic content of samples rich in inorganic salts, even if limits of detection are degraded in some cases. − Samples collected during future missions to ocean worlds could contain high levels of salts that are challenging to directly analyze by other techniques in development for flight, where sample preparation steps are typically performed. − Additionally, CE operates on high voltage (10–30 kV) only, and its full automation can be achieved with a relatively modest number of mechanically moving parts. − Over the past decade, instrumental advances in CE have been primarily focused on achieving portability, automation, and integration with advanced detectors or sample preparation methods for specific applications. These efforts have been largely enabled by miniaturization, integration, and 3D printing .…”