| This paper summarized the Flash LC, MLC, UHPLC and HTLC, and focused on thehigh-pressure and high-temperature-related problems and solutions. The effect of flow rateand temperature on retention was studied. The increase in pressure (flow rate) couldgreatly accelerate separation speed. Elevation of temperature could raised the optimumvelocity, decreased column back pressure, enhanced resolution, adjusted selective andreduced the asymmetry to improve the peaks.Based on sub-2μm column, an UHPLC system was constructed. This system couldgenerate maximum pressure at 60MPa; system stability was good enough to meet thequantitative and qualitative analysis. In the analysis of the standard sample, compared with5μm, columns packed with 1.9μm particles was more faster, and it's 8 times faster whenseparated at the same velocity and only 1/14 of solvent consumption.The conventional HPLC was modified to HTLC system. Separations of LiuweiDihuang Pill under different mode were used to evaluate the HTLC system. Separation ofLiuwei Dihuang Pill used HTLC achieved faster and high through-put analysis, and easy tocreate sophisticated fingerprint. If 4 columns used in series, the absolute plate numberreached 7.6M, peaks of Liuwei Dihuang Pill timed, especially the antecedent peak of theless retained components got enough separation and the fingerprint of sample was morecomprehensive. Continues two-dimensional chromatography system constituted of normaland reverse columns speeded up the separation speed. The mode of UV and ELSD in serialhad feature of high sensitivity and universal which gave more detailed information. |
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