Chromatography Forum

we use a hplc for analysis and filter the mobil phase and samples with 0.45 micrometer and after column before detector we have a filter with 0.2 micrometer but detector blocked. and we checked after filter there is no block!!!!! and mobile phase comes out without problem!!!!! but detector blocked.

Backflush through the detector, to waste. Use a slower flow rate as necessary.

thank you Consumer Products Guy

after washing somtimes it is ok, and safter days it blocked again hahaha, but the point is i want to know only particles can block the detector or any other thing or reason can be block it? I mean some solutions!!!!!

What detector do you have? Is it posible that perhaps capilary is twisted so it is blocking the detector. Did you used buffer solutions before, and maybe after alcohol, without flushing the system.

I once had the capillary just before the flow cell in a detector get clogged, have no idea how it happened, wasn't running buffers. So for me once in 30 years. I replaced that capillary, could not flush it free in my case.

Hey Miumiu,

On your first post you said "after filter there is no block" After filter means just the detector right so the filter is just blocked?

I plugged the 0.010" inlet tubing to an Agilent UV detector one time and had to replace the tubing. Probably a particle but
that would have to be a big chunk.

we have a filter after column just before the detector RI detector, there is flow after filter and for sure detector blocked hahah, we have a 0.2 filter how is it possible detector blocked after this filter?

How old is filter? What kind of filter? Are you running solvents thru it? Acids? Perhaps the filter is compromised in some way allowing something to pass through. Who was running it? You say We have a flowing filter. A flowing filter could still be compromised. Is the filter sealed or can you open it and replace the filter? Were you running a buffer and then flush with pure organic find the problem flush with water then filter clean, but detector not? What was Mobile Phase composition before problem?

can you give a little more details of your application?
when you say it is blocked,
what symptoms are problematic for you?
the pressure build up?
the detector going blind?

are you using buffers? what type? if not then what do you use as mobile phase?
what are the samples nature?
are you using high temp in the oven? and what is used in the RI?