3.1.1 Reversed Phase-High Performance Liquid Chromatography
Nowadays, Reversed Phase-High Performance Liquid Chromatography (RP - HPLC) separation technology is the main method of impurities separation in pharmaceuticals. 35-37 Some new mobile phases and stationary phases have also been studied and applied for the separation of various complex samples. For example, ionic liquids can be used as mobile phase additives to significantly improve the separation effect of components, suppress tailing of chromatographic peaks and shorten analysis time by inhibiting the harmful effect of free residuals of silanol groups in the stationary phase. 38 High temperature liquid chromatography technology can increase the resolution of chromatographic peaks and the analysis speed by increasing the temperature of the chromatographic column. Edgar et al.39 used high temperature liquid chromatography-tandem mass spectroscopy to determine nine high-intensity sweeteners in a variety of drink samples, and consume only 0.85 m L of a green organic solvent (ethanol). There are also some scholars who introduce quality-by-design principles when they establish analysis methods to obtain the best analysis method, so as to save analysis time and mobile phase consumption. 40