Normal Phase SPE Cartridges are the process of dissolving polar substances in non-polar solvents (diethyl ether, n-butane, etc.), and being adsorbed by a strong polar stationary phase. The forces between the two include dipole pairs, hydrogen bonds, Electronic pairs. Commonly used adsorbents are alumina, magnesium silicate, diatomaceous earth, and silica gel.
Stationary phase (filler) of normal phase SPE cartridges: polar substances. Separation objects of normal phase SPE cartridges: polar, medium polarity, non-polar. Mobile phase (eluent) for normal phase SPE cartridges: non-polar, medium-polarity. Forces between adsorbent and compound for normal phase SPE cartridges: hydrogen bond, π-π bond, etc. Commonly used normal phase solid phase extraction columns: ① Polar functional group bonded silica gel such as -CN, -NH2; ② Polar adsorption substances such as Silica, Florisil, Alumina.