Optimization Of Microflow Evaporative Light Scattering Detector And Its Coupling With Pressurized Capillary Electrochromatography

Pressurized capillary electrochromatography(pCEC) is based oncapillary electrochromatography(CEC), which has the characteristics ofhigh column efficiency, high selectivity, high resolution and fast separationspeed, using dual driving forces of pressure flow and electroosmotic flow.It is easily integrated with other detectors to use on line. Therefore it hasbeen widely used in fields of biochemical analysis, chiral separation,neuroscience, protein and peptide research, pharmaceutical analysis withunparalleled advantage in the analysis of complex samples. UV,electrochemical detectors, laser-induced fluorescence, NMR and massspectrometry are have been used for pECE detection. However, there is nouniversal detector, such as evaporative light scattering detector in HPLC,available for pCEC. ELSD is a kind of universal detector, by which allsamples with lower volatile compared to mobile phase can be detected. Itis not restricted by the structure of the material itself, which is appliedwidely in the fields of food safety, analysis of pharmaceutical andtraditional Chinese medicine. It is of great significance to miniaturizeELSD and achieve the combination with pCEC. This study, baded on ainitially built microfluidic ELSD, we optimized the evaporation system ofthe detector, making breakthrough to reduce the flow rate of atomizationcarrier gas, improving peak shape, enhancing the evaporation capacity ofthe system and expanding the application scope of the instrument. Thesources of the detection background noise are investigated. A novel separation system of microflow evaporative light scattering detector(μELSD) coupled with pCEC was built and applied to the separation anddetection of notoginsenoside R1, ginsenoside Rg1, ginsenoside Re,ginsenoside Rb1, ginsenoside Rd in traditional Chinese medicine extractXuesaitong (lyophilization). The results show that the pCEC-μELSDsystem can be used for determination the content of active ingredients inmedicines. The construction of μELSD provides an innovative detectionmeans for capillary liquid chromatography(cLC), pCEC and capillaryelectrophoresis(CE).