rear seal wash in normal phase

[RALS]

Hi There

I am using normal-phase (hexane and isopropanol) and they advice me to use rear seal wash water isopropanol 40:60. It was fine for some time but it seems that the detector is not detecting the solution. Any other suggestion for the composition of the rear seal wash?
thanks

[tom jupille]

The detector should *not* detect the seal wash solution. The only situation where I can see that happening is if the seals are in very bad shape, and in that situation I would expect the first symptom to be mobile phase in the wash.

[uzman]

No need to seal wash for normal-phase , it is usually required for reverse -phase mobile phases ,containing salts.
When reverse-phase solvents evaporate at the back side of the piston , it leaves salt deposits behind , which shorten the life of both the piston and seal and causes leaks.

Normal phase mobile phases ; like hexan and IPA ; easily evaporate at the back side of the piston , leaving nothing behind it.