Guard columns can provide many benefits when used upstream from an analytical, preparative, or semi-preparative column. Guard columns are typically chosen to have the same packing as the primary column. Any compounds or particulate material that would block the frits or highly adsorb to the primary column will do so on the guard column, thereby protecting and extending the lifetime of the more costly column. In addition to protective uses, guard columns can be used as sacrificial preparative components. Use female luer, male luer, luer lock and barbed fittings to connect syringes, equipment or other devices to valves.