Hydroquinone as an Inhibitor

[brendandamm]

Hello everybody

So I run a ton of different latex and resins through the HPLC for quantitative analysis of certain preservatives and the result of all those resins passing through my column is terrible clogging, high pressure, etc. I’ve talked to the column manufacturer about this issue and he believes the problem is coming from the Styrene monomer accumulating and agglomerating on the carbon chains, which continue to build on each other and thus causes the clogging. Makes sense. He recommended adding a small amount of hydroquinone to be used to inhibit that styrene monomer from forming which would ultimately extend the life-time of the column. So my question is:
A. Has anybody ever tried this before? Is it worth giving it a try?
B. What amount of hydroquinone would I need to add to each sample to make sure its effective?
C. How often would I need to remake the hydroquinone solution?


Thanks

[HippyLabRat]

What's in your mobile phase?

[Gerhard Kratz]

How many injections you can run on a column? What is the high back pressure? What sample preparation you are doing?

[brendandamm]

Mobile phase is 10%MeOH/90%H20 with a built in column flush that kicks it up to 100%MeOH after 4 mins, then 100%MeOH for 5 mins before re-equilibrating the column back to the starting mobile phase.

The backpressure starts at ~80bar during the starting mobile phase on a new column. After about 100 injections of the resin the backpressure can be anywhere from 200-350bar.

sample prep is 50:1 dilution in H20. Sonication for 15 mins. Centrifuge at 12500rpm for 15 mins. Filtration through 0.2um filter.

[Gerhard Kratz]

I'm not worried about 100 injections and also 200 to 350 bar is still something to live with.
Do you use a guard column? Sample prep seems to be ok.

[brendandamm]

Well I run at a minimum 100 samples per week so burning through a column every week is turning into an issue for us. A guard column is used but has no effect on the column lifetime. I'm changing the guard column every 30-40 injections

[Gerhard Kratz]

What particle size and column dimension you use?

[bunnahabhain]

Do you see a shift in retention time during these 100 runs? If it is agglomeration of some monomers, it would definitely affect retention time because the retention mechanism is affected by agglomerates.
If the guard column has no benefit, why do you change it then?
Did you already try to regenerate your column? Have a look at this document by Sigma Aldrich for some ideas on how to clean your column.