Enhanced capillary zone electrophoresis in cyclic olefin copolymer microchannels using the combination of dynamic and static coatings for rapid analysis of carnosine and niacinamide in cosmetics.

Cosmetics that have medicinal effects, including anti-inflammatory and antioxidant, have become a daily care routine consumption. The peptide additives, such as carnosine and nicotinamide, were frequently used to realize these medicinal effects. To accomplish rapid and effective quantitation of carnosine and niacinamide in cosmetics, capillary zone electrophoresis was executed in cyclic olefin copolymer microchips having both dynamic and static coatings. The static coating of cyclic olefin copolymer microchannel was constructed from bovine serum albumin adsorption, immobilization, and active site closure, while the dynamic coating was formed by adding surfactant into running buffer of capillary zone electrophoresis. The static coating can improve the hydrophilicity of cyclic olefin copolymer surface and avoid nonspecific peptide adsorption. The dynamic coating of sodium dodecyl sulfate in running buffer proved to be useful in flow velocity adjustment and the column efficiency enhancement in the capillary zone electrophoresis separation channel of the cyclic olefin copolymer microchip device. A separation resolution up to 4.24 on the mixture of carnosine and nicotinamide was obtained. Moreover, an analysis method was established and applied to simultaneous carnosine and nicotinamide determination in a liquid whitening essence and a solid antiglycation pill, and the results were verified by comparison with high-performance liquid chromatography methods, indicating its potential in complex sample analysis.

Chen Y ，Xia L ，Xiao X ，Li G ... -  《-》

[Surface-modified microchip electrophoretic separation and analysis of functional components in health care products].

Lau WC ，Chen YL ，Xia L ，Xiao XH ，Li GK ... -  《-》

[Analysis of three antipyretic analgesic drugs by open-tubular capillary electrochromatography].

Liu L ，Qiao J ，Zhang H ，Qi L ... -  《-》

Microchip electrophoresis with background electrolyte containing polyacrylic acid and high content organic solvent in cyclic olefin copolymer microchips for easily adsorbed dyes.

Plastic microchips can significantly reduce the fabrication cost but the adsorption of some analytes limits their application. In this work, background electrolyte containing ionic polymer and high content of organic solvent was adopted to eliminate the analyte adsorption and achieve highly efficient separation in microchip electrophoresis. Two dyes, rhodamine 6G (Rh6G) and rhodamine B (RhB) were used as the model analytes. By using methanol as the organic solvent and polyacrylic acid (PAA) as a multifunctional additive, successful separation of the two dyes within 75μm id. microchannels was realized. The role of PAA is multiple, including viscosity regulator, selectivity modifier and active additive for counteracting analyte adsorption on the microchannel surface. The number of theoretical plate of 7.0×10(5)/m was attained within an effective separation distance of 2cm using background electrolyte consisting 80% methanol, 0.36% PAA and 30mmol/L phosphate at pH 5.0. Under optimized conditions, relative standard deviations of Rh6G and RhB detection (n=5) were no more than 1.5% for migration time and 2.0% for peak area, respectively. The limit of detection (S/N=3) was 0.1nmol/L for Rh6G. The proposed technique was applied in the determination of both Rh6G and RhB in chilli powder and lipstick samples with satisfactory recoveries of 81.3-103.7%.

Wei X ，Sun P ，Yang S ，Zhao L ，Wu J ，Li F ，Pu Q ... -  《-》

High performance of cyclic olefin copolymer-based capillary electrophoretic chips.

Roy S ，Das T ，Yue CY 《-》