On‐line synergistic stacking in capillary zone electrophoresis featuring field‐amplified sample stacking and micelle to cyclodextrin stacking in the determination of two alkaloids in complicated matrix samples

Abstract

A novel on‐line synergistic proconcentration strategy coupling field‐amplified sample stacking and micelle to cyclodextrin stacking for cationic analytes in capillary zone electrophoresis has been proposed and applied for the separation and determination of two alkaloids, matrine, and oxymatrine in complicated matrix samples. The approach was performed by the long injection of sample in a low‐conductivity sodium dodecyl benzene sulfonate solution followed by the injection of hydroxypropyl‐β‐cyclodextrin solution in higher conductivity. The stacking mechanism of this method has been expounded and parameters affecting stacking effect have been optimized in our study. Under the optimum experimental conditions, 169‐ and 218‐fold sensitivity improvements were achieved for matrine and oxymatrine when compared with normal injection. Analytical indicators including linearity, limits of detection, and reproducibility (intra‐ and inter‐day relative standard deviations) were evaluated. Moreover, sample matrix effect was studied using compound flavescent sophora and salicylic acid powder and spiked urine samples. The developed method is an attempt for the combination of micelle to cyclodextrin stacking with other stacking methods. It could be a good alternative choice for the determination of alkaloids in a complex sample matrix.

A simple and efficient sequential electrokinetic and hydrodynamic injections in micellar electrokinetic chromatography method for quantification of anticancer drug 5‐fluorouracil and its metabolite in human plasma

“…This was due to the higher buffer concentration contributing to a bigger conductivity difference between the sample and BGE, which is favorable to an enrichment effect. However, more Joule heating was also generated owing to the high concentration of electrolyte (50 m m ), leading to a decrease in signal sensitivity and enrichment of analytes (C. Chu et al, 2019). Thus, 45 m m of NaH 2 PO 4 in BGE was used in the subsequent experiments.…”

“…It was found that the peak area of 5‐FU increased as the SDS concentration increased from 10 to 50 m m , and then dropped at 60 m m of SDS (Figure 3c). This was expected because high concentration of SDS could result in strong interaction between micelle and analytes, which increased the difficulty of reversing the effective electrophoretic mobility and thereby caused the suppression of signal sensitivity (C. Chu et al, 2019). The peak area did not further increase at SDS concentration >50 m m ; thus, 50 m m was used for further optimization.…”

Electroanalysis based on stand-alone matrices and electrode-modifying films with silica sol-gel frameworks: a review

“…A templating agent that is analogous to a surfactant is stacked CD. With its characteristic open pore channels when stacked (The CD structure is one of a truncated cone), it has been shown to be well-suited to separation methods [70]. For pore formation in sol-gel films on electrodes, it overlaps EASA in terms of size domain [22,26], but unlike a surfactant, CD does not influence the structure or strength of the bulk portion of the silica film [28,71].…”

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

“…Recently, dual or multiple focusing techniques were explored as alternatives for further improving the detection sensitivity. Some of these techniques are ITP‐stacking [22], field‐amplified sample stacking‐moving reaction boundary [23], field‐amplified sample stacking‐micelle to cyclodextrin stacking [24], and ionic liquid micelle based three‐step stacking [25].…”