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

Abstract

Capillary electrophoresis (CE) has been developed as one of the powerful separation techniques for the analysis of inorganic and organic ions in complex matrices in the recent past. In aqueous samples, most of the inorganic ions are having weak absorption profiles in the UV-Vis region of the spectrum. These low absorption profile ionic species are commonly detected by indirect UV absorbance with the addition of an absorbing co-ion (chromophore) into the electrolyte. The inorganic cations oftenly require an additional complexing agent to selectively alter their similar mobilities and proper separation. The indirect detection at 214 nm was performed with α-hydroxyisobutyric acid (α-HIBA)-4-aminopyridine background electrolyte (BGE) that has a characteristic absorbance at 214 nm. The BGE was applied for the separation, analysis, and validation of metal ions in water samples. The metal ions such as K+, Na+, Ca2+, Mg2+, Mn2+, Fe2+, Cd2+, Pb2+, Ni2+ and Zn2+ were separated successfully in this study. Also, the effect of electrolyte pH, applied voltage and injection time for the separation of cations was investigated.

Development of a background electrolyte for the determination of inorganic cations in high ionic strength samples by capillary electrophoresis with indirect UV-absorption detection

“…resolution, separation efficiency, sensitivity and limit of detection), sample ionic strength should be less or similar to the BGE ionic strength. In this context, most of the published literature tends to minimize the BGE concentration and ionic strength, aiming to improve the limits of detection (LOD) [2,7,[20][21][22][23][24]. For instance, several applications have been reported for inorganic ions in low ionic strength samples such as active pharmaceutical ingredients [25], clean water sources [13,22,26] or very diluted high ionic strength samples [27].…”