Welch preparative guard column cartridges use the same packing as the preparative column, which can intercept some of the same polar substances in the sample and prevent them from contaminating and damaging the packing materials in the preparative column. 10×10mm cartridge holder: 00808-01116, 21.2×10mm cartridge holder: 00808-01106, 30×10mm cartridge holder: 00808-01117, 50×10mm cartridge holder: 00808-01110.Ultisil XB-C18 is one of the most versatile C18 analytical columns on the market. It features advanced bonding and double-endcapping technology, delivering nearly perfect peak shapes. This column is ideal for analyzing complex matrix samples and provides excellent peak shapes for acidic and basic compounds. It is particularly effective for the separation of traditional Chinese medicine compounds.