Abstract
Reverse-phase liquid chromatography has been predominantly used for separation of analytes in the
pharmaceutical industry. RP-HPLC consists of polar mobile phase and non-polar stationary phase. In reverse
phase-liquid chromatography (RP-LC), the stationary phase is the layer of hydrophobic groups bonded to silica
solid support materials. Most commonly used stationary phases in RP-LC are C8 and C18, which offer efficient
separation of few selective polar compounds. But, these phases are not suitable for separation of complex
mixtures in exotic buffer systems, extreme pH conditions and with complex mobile preparations. Hence,
chromatographic retention and separation of polar compounds continues to be a challenging analytical problem.
As a solution to this problem, newer stationary phases have been discovered and employed commercially. They
offer the flexibility to use simpler mobile phases thereby avoiding ion-pair reagents, exotic buffer systems,
extreme pH conditions and complex mobile preparations. The newer stationary phases developed in recent years
are Polar-embedded alkyl phases, Fluorinated phases, Alkyl C30 phases, Hydrophilic interaction chromatography
(HILIC) phases, Nanomaterial based, Type-C and Monoliths. This review covers the extensive experimental work
done by various scientists on the newer stationary phases. It can be used by other researchers for further studies
regarding separation science.
KEYWORDS: Stationary Phase, RP-LC, HILIC, Monoliths.