On-column liquid-liquid-liquid microextraction coupled with base stacking as a dual preconcentration method for capillary zone electrophoresis.

A simple and efficient dual preconcentration method of on-column liquid-liquid-liquid microextraction (LLLME) coupled with base stacking was developed for capillary zone electrophoresis (CZE) in this paper. Four N-methyl carbamates were used as target compounds to evaluate the enrichment means. The carbamates in sample solutions (donor phase) were extracted into a dodecanol phase immobilized on a porous hollow fiber, hydrolyzed and back extracted into 0.

Determination of kanamycin A, amikacin and tobramycin residues in milk by capillary zone electrophoresis with post-column derivatization and laser-induced fluorescence detection.

An analytical method for kanamycin A, amikacin and tobramycin of aminoglycoside (AG) antibiotics in milk samples was proposed using capillary zone electrophoresis (CZE) with post-column derivatization and laser-induced fluorescence detection. A simple and convenient homemade coaxial-gap reactor was adopted in the post-column derivatization of the AGs with 1.0 mmol/L naphthalene-2,3-dicarboxaldehyde and 8.

Determination of benzoic acid and sorbic acid in food products using electrokinetic flow analysis-ion pair solid phase extraction-capillary zone electrophoresis.

An electrokinetic flow analysis system (EFA), consisting of one electroosmotic pump, five solenoid valves and one on-line homemade solid phase extraction (SPE) unit, combined with capillary zone electrophoresis (CZE) was proposed to determine benzoic acid and sorbic acid in food products. Tetrabutylammonium bromide (TBAB) was adopted as an ion pair reagent to improve the retention of the preservatives on C(8)-bonded silica sorbent, which was also used to remove sample matrices. By using the SPE unit, the EFA-SPE-CZE system was able to perform the SPE operation and CZE separation simultaneously.

Post-column reactor of coaxial-gap mode for laser-induced fluorescence detection in capillary electrophoresis.

A post-column reactor with coaxial-gap mode is developed for laser-induced fluorescence detection (LIF) in capillary electrophoresis (CE). The reactor can be assembled simply and conveniently, in which a thin polyimide sleeve of 10-mm length obtained from the capillary coating is used to align separation and reaction capillary with a 20 microm gap. Naphthalene-2,3-dicarboxaldehyde and 2-mercaptoethanol are used as derivatization reagents and delivered into the reaction capillary through the annulus between the separation capillary and polyimide sleeve and the gap of two capillaries by gravity.

Determination of amino acids in tobacco samples by capillary electrophoresis/indirect absorbance detection with isolation of the electrolysis compartment and p-Aminobenzoic acid as a background electrolyte.

A fast, convenient and sensitive method of capillary zone electrophoresis (CZE) and indirect UV detection was proposed for the determination of 16 amino acids. p-Aminobenzoic acid (PAB) was selected as a background electrolyte (BGE). An isolated cell included a BGE buffer part and an electrode buffer one, which were jointed with a glass frit.