PTFE frit in Quat Pump always dirty

Question

Hello! I have slightly increased the amount of use my HPLC gets but I am having to change the PTFE frit in the Quat pump what seems like a lot more often. Probably once to twice a month. Is there anything else that anyone thinks that could be causing it to get dirty? Or is it more likely to just be from just the increased usage? We do not have a normal maintenance routine as we are a very small company. I am working on developing one. Thank you for any help you can provide!

ETA: I am having pressure issues when this happens and causes it to stop working. I forgot to mention this.

sschombu · Accepted Answer

Usually discoloration of the PTFE frit is nothing to worry about. As long as the pressure with open purge valve is below 5-10 bar, while pumping, there is no reason to replace it. That's its function - to filter out any dirt and particles from the solvents. Of course, proper housekeeping should be in place (statements below are for 1290 system, but can also be applied to any HPLC): - always use brown bottles, especially for ACN, but also for water and other solvents - use membrane filtration to filter solvents before usage; also true for water - don´t refill bottles. Rinse with a little fresh solvent first, then stay with volumes which are gone within two days - don´t put solvent bottles in the dishwasher, rinse with some fresh solvent, then discard the liquid - always go for gradient grade quality at least (even higher, if an MS is connected) - there are good and not so good brands on the market. We cannot recommend anything, but Agilent solvents are known good quality - do not use technical grade solvents on your LC - make sure the glass filter frits are on. Replace them on a regular basis. Do not clean/boil/sonicate them - no water, buffer or ACN to be left in the system, if not in use for more than two days - We also recommend flushing the entire LC with IPA on a regular basis. Before using the instrument again, flush thoroughly with fresh water. Make sure the instrument gets a PM on an annual basis

johnbradley · Answer

So we had this problem when we first starting using the 1260 systems. We would add a standard column (100 x 3.0mm), and after less than 100 injections of solvent based material it would give us huge backpressures and stop the injections. We blamed the column manufacturer at first, so switched to another column from Agilent, and it still happened. We changed various tubing, heat exchangers, and frits for the solvent lines, all with only short-term success.

We eventually traced it back to needing to filter our mobile phase solutions. We now filter absolutely everything attached to a HPLC line using 0.2um nylon filters. We also added a pre-column filter (0.2 or 0.5um) and a guard column and now we have no pressure issues. We change the filters when we see poor peak shape, or increasing pressures (we follow the pressure profile for each batch). We also try to flush out the HPLC system every 6 months, there's a HPLC flushing solvent available from Agilent which we use, and I can send you on the protocol we use if you want.

So, filter everything, and clean your HPLC before you try doing more injections, otherwise we only got temporary relief of the pressure buildup. Our systems were brand new when we experienced these issues.

Hope this helps!

John.

Kieran · Answer

You can access the Lab Advisor download page at the following link: https://www.agilent.com/en/product/liquid-chromatography/hplc-ce-software/instrument-control-software/lab-advisor-software . The software may not work on older versions of Windows, so make sure you are using a Windows 10 PC if possible.

PTFE frit in Quat Pump always dirty

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