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