yellow seals normal phase / black seals reverse phase

Please do not change from the default yellow normal phase to black on a 1290 Infinity II pump (G4220X, G7104X, G7120X). There are special valves for normal phase applications as well.   Which model pump do you have?    

But for the 1260 you can swap the seals and use either the normal phase or reverse phase seals. (G131X, G711X)

"For running normal phase applications on Agilent Infinity and Infinity II pumps, yellow PE seals are required as piston seals. By default, 1290 Infinity, 1290 Infinity II, and 1260 Infinity II Flexible Pumps use ceramic pistons and yellow PE seals as piston seals. 1260 Infinity I/II pumps use sapphire pistons and black PTFE piston seals in a standard configuration. If using black PTFE seals with normal phase applications, the black PTFE seals wear and generate small particles. Such particles can clog valves and other parts in the flow path. When running normal phase applications on 1260 Infinity I/II pumps, the piston seals have to be changed to yellow PE seals. For optimum performance, PE seals should be replaced during preventive maintenance."

See page 60 of the user's manual: 1290 Infinity II High-Speed Pumps Agilent InfinityLab LC Series User Manual

jhagel is correct, do not change PE (Yellow) to PTFE (black) seals in round headed pumps (1290 Infinity and Infinity II as well as G7014C).

Both seal types have benefits and downsides:

While the black seals are generally better when using them with reverse phase applications they can easily disturb the chromatography when used with nonpolar solvents like Hexane. They are not suitable for applications running higher than 600 bar but these seals work better with Sapphire Pistons. 

The PE seals are more universal as they are working at higher pressures and with all solvents, but need special attention, like a running seal wash and buffer precipitation can lead to earlier fails of the seals.

Azrael When designing the pumps we had all of these and more factors in mind to give the pump heads the best performance with highest possible robustness. Changing to PE seals in the 1260 pumps is only recommended when using nonpolar solvents but is not needed in 1290 pumps.

Hi,

This is interesting. The manual for the 1260 Isocratic pump (both Infinity I and Infinity II versions) state that the PE seals have a more limited pressure range (up to 200 Bar) is this because they are being used with sapphire pistons in this case?. Also if we are using 1260 pumps isocratically with water or buffer solutions it seems that we should be using the black PTFE seals - in the past I thought I'd been told to use the PE seals in the case, but it looks like this is incorrect? 

Many Thanks,

Jenny

Hi jens, There are many reasons why we recommend the 200 bar limit for PE seals in 1260 pumps when used with nonpolar solvents, one of them is the piston. I would always use the black PTFE seals in the 1260 pumps unless nonpolar solvents are used, so in your case the black ones should work fine.

But please don't get me wrong, the 1260 pumps will work reliably with both seal types, it is the application which determines which seal to use.  

tobknust Why then use sapphire pistons if there are ceramic pistons? I'm interested. I ask you to understand me correctly, but superficial answers do not satisfy me. You can also use a ceramic piston with a polyethylene seal in many solutions. Are ceramic pistons expensive?

tobknust Why then use sapphire pistons if there are ceramic pistons? I'm interested. I ask you to understand me correctly, but superficial answers do not satisfy me. You can also use a ceramic piston with a polyethylene seal in many solutions. Are ceramic pistons expensive?

Hi Azrael, never change a running system. The PTFE/sapphire combination is tested a million times. Sapphire and ceramic pistons have different physical and surface properties but we need the more expensive ceramic pistons in the 1290 for several reasons. 

Hi tobknust! 

Ok, thank you for  answer

regards Azrael