Normal-phase chromatography employs a polar stationary phase and a non-polar mobile phase to separate compounds based on their polarity. Less polar compounds are eluted first, followed by more polar compounds, enabling effective separation. This technique, widely used in HPLC, is versatile and advantageous for separating a variety of compounds, including water-sensitive substances, geometric isomers, cis-trans isomers, and chiral compounds. It is valuable in pharmaceutical research, natural product analysis, and environmental monitoring, assisting researchers in understanding the structure and characteristics of diverse compounds.