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- Posts: 2
- Joined: Sun Jan 28, 2018 8:13 am
I'm using Waters RI Detector 2414 and I run filtered culture supernatant as my samples to detect sugar utilization in E. coli. I hope someone could help me answer these problems I'm facing.
1. I often encountered LED intensity low error message after running the hplc for about a week and injecting about 70 samples. I asked the branch's Waters Engineer and he suspected the flow cell line was contaminated. Thus I tried cleaning with 6N nitric acid as recommended in the manual, it worked, but the problem surfaced again when I run the my samples again. The question is, how do I deal with this? I've been running this type of samples for over 3 years now without any problem, and this problem only surfaced recently. I prep my samples by centrifuging 13000 rpm for 10min and filtering through 0.2 micron nylon membrane.
2. Would frequent cleaning with nitric acid cause any damaging effect to our system?
3. In the procedure done for flow cell cleaning, it says to avoid getting the nitric acid into the reference flow cell (purge). However, I suspect that the reference cell line is also contaminated, because the pressure increase about 30 psi when I start purging. Is there any suggestion to what solvent I could use to clean this part too? I read some people use 10% phosporic acid for cleaning, but no information if it is safe for reference cell part too.
Please help me.
Thanks