Different strategies for the preconcentration and separation of parabens by capillary electrophoresis

Abstract

Several strategies, namely, large volume sample stacking (LVSS), field-amplified sample injection (FASI), sweeping, and in-line SPE-CE, were investigated for the simultaneous separation and preconcentration of a group of parabens. A BGE consisting of 20 mM sodium dihydrogenphosphate (pH 2.28) and 150 mM SDS with 15% ACN was used for the separation and preconcentration of the compounds by sweeping, and a BGE consisting of 30 mM sodium borate (pH 9.5) was used for the separation and preconcentration of the compounds by LVSS, FASI, and in-line SPE-CE. Several factors affecting the preconcentration process were investigated in order to obtain the maximum enhancement of sensitivity. The LODs obtained for parabens were in the range of 18-27, 3-4, 2, and 0.01-0.02 ng/mL, and the sensitivity evaluated in terms of LODs was improved up to 29-, 77-, 120-, and 18,400-fold for sweeping, LVSS, FASI, and in-line SPE-CE, respectively. These preconcentration techniques showed potential as good strategies for focusing parabens. The four methods were validated with standard samples to show the potential of these techniques for future applications in real samples, such as biological and environmental samples.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…In general, these additives can be obtained from nature or manufactured by the chemical industry. The main food additives analyzed by CE in the period covered by this review (2013–2015) were sweeteners , preservatives , and colorants .…”

“…Another approach to increase paraben sensitivity is to use on‐column preconcentration strategies prior to CE separation. In this line LVSS, FASI, sweeping, and in‐line SPE‐CE, were investigated for the simultaneous separation and preconcentration of a group of parabens . Methods were optimized for the determination of methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben, and benzylparaben and were validated in water samples.…”

Trace determination of tetracyclines in water samples by capillary zone electrophoresis combining off-line and on-line sample preconcentration

“…B) showed that it was possible to fill the whole volume of the capillary applying a pressure of 1 bar during 1 min. This pressure allows to inject a high sample volume in a shorter time in contrast with other papers in which a higher injection time was applied using lower pressures . The negative voltage (anodic voltage) was checked from −20 to −30 kV.…”

In‐line SPE‐CE using a fritless bead string design—Application for the analysis of organic sulfonates including inline SPE‐CE‐MS for APTS‐labeled glycans

“…In addition, there are often problems with reproducibility, associated with the process of reproducibly loading and elution . (iii) Packed beds are most commonly used in in‐line SPE‐CE and have been used in many analytical applications . There are different approaches for the construction of a packed bed capillary.…”

“…In addition, frits are vulnerable for bubble formation, disrupting the separation. Therefore, fritless packed bed capillaries have been constructed in recent years . In general, the capillary consists of three individual pieces.…”