HPLC high performance liquid back-pressure

Most high-performance liquid chromatography (HPLC) pumps can be used in HOPC. The back pressure rating should be at least several thousand pounds per square inch (a few hundred kg/cm ). A type of pump that does not allow bypassing the pressure transducer or a pulse damper, if it is installed, must not be used. The dead volume should be as small as possible. Pumps with a single plunger are better than those with two plungers. 

Particulates from the sample matrix that are carried over during the sample preparation should be removed prior to analysis by either high-performance liquid chromatography (HPLC) or gas chromatography (GC). This is especially true for particles less than 2 /un in size. These particulates will pass through the frits on a liquid chromatographic column and settle on top of the sorbent which will eventually cause an increase in the back pressure of the chromatographic system and susequently decrease the column performance. 

However, to increase separation efficiency, high velocities and small-diameter (<10pm) particles are essential as the stationary phase. Unfortunately, this leads to an increase in back-pressure. To overcome this back-pressure, a pump is necessary for transport of the mobile phase (high-pressure- or high-performance liquid chromatography, HPLC). Separation is performed in a closed system. 

---