Hardware and Tools—System Pacification

The first step in the wetted path in the HPLC is the solvent reservoir holding freshly filtered (and possibly degassed or deoxygenated) solvent. Most systems use a porous fritted stone (5-30-/an filter) as a solvent line sinker. The tubing to the solvent inlet is wide-diameter Teflon . In the solvent inlet line we may have another frit and a sapphire ball/stainless steel check valve. The wetted surfaces in the pumping chamber are all stainless steel except for the plunger 

HPLC A Practical User s Guide, Second Edition, by Marvin C. McMaster Copyright 2007 by John Wiley Sons, Inc. 

The injector s wetted surfaces are stainless steel and acid-washed tubing, except for the rotor seal. The seal is a block of beryl or carbon liber-impregnated Teflon , like the pump seal, drilled for the loop and bypass pathways. Movement from inject to load is sealed and lubricated by the Teflon face plate. The injector outlet is drilled to 0.01 in and equipped with a compression fitting carrying tubing of the same diameter. 

The next step in the pathway is the column. The compression fitting on the inlet end-cap leads to the stainless steel frit at the top of the column. The column itself is a heavy-walled stainless steel tube filled with packing and mobile phase. The outlet end is identical to the inlet. Moving on down the wetted surface, we find 0.01-in tubing leading to the detector flow cell. 

The detector inlet usually passes through a coiled stainless steel tubing heat exchanger and into the flow cell. The flow cell is the most complicated part in the system. The body is stainless steel or quartz, windows are quartz, and, if it can be taken apart for cleaning, there is usually a Teflon gasket between the stainless steel body and the quartz window. Finally, we move out of the flow cell into the wide-diameter Teflon tubing of the outlet tubing and into a backpressure device in the waste vessel. 

---