Hyphenation of field‐amplified sample injection and transient isotachophoresis in CE for the determination of sotalol and metoprolol in human urine samples

Abstract

A sensitive approach of capillary electrophoresis coupled with field-amplified sample injection and transient isotachophoresis was developed for the simultaneous determination of two β-blockers: sotalol and metoprolol. In this dual focusing technique, the samples were prepared via only dissolution in ultrapure water and then injected electrokinetically. Phosphate acted as both the background electrolyte and the leading electrolyte. Its optimized concentration was 80 mM. A total of 25 mM of glycine was used as the terminating electrolyte. Under optimum conditions, good separation of sotalol and metoprolol was achieved within 10 min. In comparison with the conventional method, the sensitivity enhancement factors were up to 1031 and 919 for sotalol and metoprolol, respectively. The proposed method was employed in the determination of sotalol and metoprolol in spiked human urine samples. The limits of detection and limits of quantitation obtained via ultraviolet detection were 5 and 12 ng/mL, respectively, for sotalol, and 10 and 25 ng/mL, respectively, for metoprolol. The intraday repeatability values were lower than 2.7 and 1.7% for peak area and migration time, respectively. The assay is a simple and efficient strategy with potential for application in clinical and biochemical laboratories for monitoring sotalol and metoprolol. K E Y W O R D Sβ-blockers, capillary electrophoresis, field-amplified sample injection, transient isotachophoresis

Recent Applications of Dynamic On-Line Sample Preconcentration Techniques in Capillary Electrophoresis

“…In the transient ITP (tITP) technique, a sample solution in a saline matrix is preconcentrated by isotachophoresis (ITP) and subsequently the focused analytes were separated by a specific separation mode, e.g., CZE, MEKC, CGE and NACE. In the previous three years, the tITP technique has been employed to the CE analyses of bacteria [52], food additives [53], peptides [54], and β-blockers [55] as summarized in Table 4. Kawai et al proposed the coupling of tITP with LVSEP, which was named as a large volume dual preconcentration by isotachophoresis and stacking (LDIS), for single cell metabolome analysis of amino acids [56].…”

Recent (2018–2020) development in capillary electrophoresis

“…In addition, electrophoretic focusing can be hyphenated with other preconcentration methods to further improve the enrichment effect. For instance, on-line hyphenation of FASI and tITP was developed by Xu et al [14], and successful separation of sotalol and metoprolol in human urine was achieved within 10 min using phosphate as both the background and leading electrolyte, and glycine as the terminating electrolyte, with the limit of detection (LOD) and limit of quantitation (LOQ) for both compounds lower than 25 ng/ mL. tITP was also coupled with LVSS by Kawai and coauthors to provide high salt tolerance to up to 10 mM NaCl in CE without losing resolution [15].…”

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

“…On-line preconcentration strategies are simpler, more economical, and can reduce manipulation with samples, lowering the chance of errors compared to offline preconcentration methods. Therefore, on-line sample preconcentration strategies could be considered the most advantageous to overcome the sensitivity limitation of CE [15][16][17][18][19].…”

“…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.…”