Phenomenex has a variety of preparative C18 columns to choose from. If the you are looking for a material that can handle large sample volumes, Luna C18(2) would be the best option. Gemini NX-C18 offers extended pH stability for high pH analyses and a different selectivity to Luna C18(2).  Kinetex core-shel columns are best suited for those who are looking for high efficiency preparative applications often where closely eluting impurities pose a problem. Kinetex C18 is also fully scalable from UHPLC to Prep so it is perfect for labs that require the same selectivity across multiple particle sizes. Luna Omega Polar C18 and PS C18 offer a different selectivity to more traditional C18 phases and would be ideal for analysts who need a different selectivity or greater retention of polar compounds.