Establishing a sensitive capillary electrophoresis-UV method for direct determination of amino acids to evaluate vinegar quality

Determination of amino acids and peptides without their pre-column derivatization by capillary electrophoresis with ultraviolet and contactless conductivity detection. An overview

This review provides an overview of recent works focusing on the determination of amino acids (AAs) and peptides using capillary electrophoresis with contactless conductivity detection and ultraviolet (UV) detection, which is the most widespread detection in capillary electromigration techniques, without pre-capillary derivatization. Available options for the UV detection of these analytes, such as indirect detection, complexation with transition metal ions, and in-capillary derivatization are described. Developments in the field of direct detection of UV-absorbing AAs and peptides as well as progress in chiral separation are described. A separate section is dedicated to using on-line sample preconcentration methods combined with capillary electrophoresis-UV.

Sensitive Analysis of Metoprolol Tartrate and Diltiazem Hydrochloride in Human Serum by Capillary Zone Electrophoresis Combining on Column Field-Amplified Sample Injection

A sensitive capillary zone electrophoresis (CZE) combined with field-amplified sample injection (FASI) method was investigated to simultaneously determine diltiazem (DI) hydrochloride and metoprolol (ME) tartrate in human serum. This method was validated by linearity, limits of detection (LOD), stability, precision and accuracy, and the related parameters are linearity (r2 > 0.9980), intra- and inter-day precisions (intra-day relative standard deviation (RSD) is 2.3-3.4%, and inter-day RSD is 3.8-7.5%) and the LOD (0.02 ng/mL for ME tartrate and 0.01 ng/mL for DI hydrochloride). So the proposed method is rapid, sensitive and accurate for determination of these two anti-anginal drugs in human serum. As for enrichment conditions, it was helpful to add phosphoric acid and isopropanol into samples for enrichment efficiency. A model was established to illustrate the possible enrichment mechanism of analytes, and a theory of half-width was also applied in CZE combined with FASI method to evaluate the peak performance.