Extra HPLC Pump Parts You Need To Have on Hand

27th Jun 2021

Extra HPLC Pump Parts You Need To Have on Hand


HPLC pumps must be able to run trouble free 24/7/365. So, in order to keep your pump in “prime” condition, we recommend planning routine maintenance and keeping commonly replaced items in your lab drawer. 

Top 5 HPLC Pump Parts To Keep in Your Lab Drawer 

  1. Inlet and Outlet Check valves 

  1. Piston Seals 

  1. Replacement HPLC Fittings (both low pressure and high pressure) 

  1. Inlet Solvent Filter 

  1. Replacement HPLC Tubing (both low-pressure and high-pressure tubing) 

  Example of Check Valves

Example of Check Valves 

1. HPLC Inlet and Outlet Check Valves and Self-Flush Check Valves 

Most check valve problems are the result of small particles interfering with the operation of the check valvesYou can try to clean the check valve, but replacing the check valve is usually required. If you notice erratic flow rate or no flow out of the outlet check valve, replacing the check valve would be the first possible solution 

 Example of polymer side vs energizer side of piston seal
Example of polymer side vs energizer side of piston seal. 

2. HPLC Piston Seals and Self-Flush Seals 

Lower than normal expected pressure, HPLC pressure variations, and leaks in the HPLC pump can all indicate possible problems with the piston seal. Depending on the solvent used, piston seal replacement is often necessary after 1000 hours of running time. 

3. Replacement HPLC Fittings (both low pressure and high pressure 

HPLC Fittings and their connections are susceptible to leaks by over tightening or not being tightened enough. PEEK tubing and PEEK fittings are especially susceptible and will need to be replaced over time to ensure a proper connection. Leaky fittings pose a common problem in HPLC, and spare HPLC fittings for both high-pressure connections and low-pressure connections should be kept in the lab drawer. If you don’t know which HPLC fitting suits your system, please contact Chrom Tech to discuss HPLC fittings. Most common, low-pressure HPLC connections are flat-bottom ¼-28 flangeless fittings. High-pressure HPLC connections are typically a coned 10-32 fitting. 

 Inlet Solvent Filter with Stem for simple connection to HPLC inlet tubing

Inlet Solvent Filter with Stem for simple connection to HPLC inlet tubing 

4. Inlet HPLC Solvent Filters 

Since many HPLC pump problems result from particulates in the mobile phase, it is important to use an inlet solvent filter in the solvent reservoir bottle. Some people call these “sinkers,” as these inlet solvent filters help hold the tubing in place at the bottom of the solvent reservoir bottle. The purpose of the inlet solvent filter is to filter out particulate matter from the solvent that may otherwise damage the piston seals, check valves, and other hardware. We recommend a 10µm or 20µm filter, so you don’t cavitate (or starve) the pump. Cavitation occurs when inlet conditions restrict the flow of solvent and vapor bubbles are formed during the inlet stroke. The key to preventing cavitation is to reduce inlet restrictions. A common cause of inlet restrictions is from a plugged inlet filter. Therefore, it is important to replace the HPLC Inlet Filters periodically, so you don’t cavitate your pump and continue to protect your downstream fluid path from particulates. 

5. Replacement HPLC Tubing (both low-pressure and high-pressure tubing)  

HPLC Inlet Tubing (Low-Pressure Tubing) 

Cavitation can also occur if the HPLC inlet tubing lines are crimped, causing restriction. Most often, HPLC inlet tubing is 1/8” Outer Diameter, 1/16” inner diameter fluoropolymer (FEP) tubing. This FEP Tubing is translucent, making it possible to watch fluid flow and watch for bubbles. 

HPLC Outlet Tubing (High-Pressure Tubing) 

After the HPLC pump, typically, high-pressure tubing is used. PEEK Tubing and Stainless Steel Tubing are the two most common materials used for High-Pressure applications. Since the outlet tubing is after the pump, it is susceptible to particles from worn seals, mobile phase particulates, or sample matrix effects. Because outlet tubing is typically a very small inner diameter, it is very susceptible to being plugged and needs to be replaced periodically. Don’t forget to keep extra Stainless Steel or PEEK tubing in your drawer. Contact Chrom Tech; as a PEEK Tubing Supplier, we keep it in stock for same-day shipment. 


To maximize uptime, it is important to keep commonly replaced items in your lab drawer. If you have any questions, please reach out to Chrom Tech support staffwe are here to help.