![]() Implement stricter regiments if this is a continual problem. Again I'm used to cleaning but I need to try to No one filters mobile phase and they use the uplcs for hplc methods (high salt content etc). Here they have a dI water system that produces about 13-15mohm water but I don't think it's filtered. I work for a small company and they have a mix of HPLC and UPLC and I used to work for a much larger company where water and solvent quality was a big concern. Will the cleaning procedure work if I can't clear a path first?Īre there additional precautions to preparing mobile phase? One more thing to add I'm willing to try the cleaning procedure you proposed but again the problem is that NOTHING comes out the outlet of the detector. We've had this happen before on this instrument and waters had to come in and replace the flow cell (very expensive) I've tried to since be diligent about cleaning after runs and not letting things sit in the flow cell by washing for an hour with 90:10 water methanol after all runs to clean out the flow cell for long term storage.Īgain if I can clean it out somehow without calling waters that would be best But the line would just pop out of the detector. I tried reversing the outlet and inlet lines and all the time running flows of 0.001-0.005ml/min just to clear a path. I don't know if this was the right idea but I prepared a solution of ph8-10 in water, primed and tried to flow through the cell to dissolve anyhing stuck then tried running a nitric acid solution(ph2 about 1 drop). Then no liquid was coming out the outlet of the detector. I removed column, put on union and confirmed that there was no leaking or extremely high pressure all the way up to the inlet of the detector. ![]() I went to investigate and noticed that I was leaking at the end of my column before the detector. It's definitely a blocked detector flow cell.Īt the end of day on Friday I was running some trial work and noticed that my peaks were distorted and broad and not eluding at the expected RT. ![]() Set up system with fresh washes, mobile phase and a very long primimg/start up then try some diluent test injections. Check pH of eluent from waste line the next morning to ensure its pH 7. If the problem is the flow cell, put all lines into first hot water (take off all sinkers and store in organic), prime up all lines for 10 mins each, then run hot water through the system (with the column disconnected, put a union it its place) for at least an hour, Repeat with Acetonitrile or Methanol, then put all lines (EXCEPT Seal Wash! Keep the seal wash line in your typical seal wash container) into a 30% Phosphoric Acid 70% HPLC Grade Water container, run at a flow of about 0.5 ml/min for at least 3-4 hours, then transfer all lines into 100% Water (again, except seal wash) and run at typical flow overnight. Try to inject a zero volume injection and monitor pressure. A long priming of about 20 minutes is often needed to clear air or blocakge from solvent lines. Prime the lines A and B individually and check for constant flow. ![]() A high reading at the check mixer inlet suggests blocked check valves. Try to isolate where the high pressure is coming from- disconnect the tubing from the mixer/pump valve selection right up to the detector, each stage putting typical flow through the system to check pressure. Also, the sinker in your mobile phase container can get blocked, do you run buffered mobile phases? A faulty mixer or dirty mobile phase buffers/additives can also increase pressure. High pressure can be as a result of many things- temperature too low on Sample Manager or not activated at all, a blocked in line filter, blocked column head not to mention particulate matter embedded into any stage of the pump mechanism or injector rotary loops etc. Are you sure its the flow cell that's causing the issue? ![]()
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