What is normal phase chromatography and how is it used in analytical chemistry?

Normal phase chromatography is a type of chromatographic technique used in analytical chemistry to separate and analyze compounds based on their polarity. In this method, a polar stationary phase, such as silica gel, is used along with a less polar mobile phase, such as a nonpolar solvent. The compounds in the sample interact differently with the stationary and mobile phases, leading to their separation based on their polarity. This technique is commonly used to analyze organic compounds, such as natural products and pharmaceuticals, in research and quality control laboratories.