Epic HILIC-RP is useful for retention and separation of polar and non-polar compounds. Reversed phase HPLC is widely used for separation of many pharmaceutical compounds. Retention and separation of many polar analytes has proven to be a challenge. Many of these types of compounds are unretained or poorly retained on most conventional reversed phase stationary phases, such as ODS. Fortunately, to deal with these types of analytes an alternative mode of chromatography can be utilized using polar stationary phases and highly organic mobile phases.