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- Posts: 84
- Joined: Wed Jan 12, 2005 6:17 pm
- Location: Georgia Southern University
Several days ago, I posted about contamination issues in a Waters 717 autosampler. A suggestion that surfaced multiple times was to change my seal pack. I just finished up that job today. That was probably a good thing to do, because Waters says it should be changed once a hear and I have had my A/S 4 years without ever changing it. So I don't regret the expense.
However, this hasn't corrected the contamination issues. When I do zero volume injections of mobile phase, there is extremely little contamination coming off. But, when I do 100 microliter injections of mobile phase (which at this time is HPLC grade mobile phase right out of the 4L amber bottle), I see the contamination. It's not exactly a small amount, reaching absorbances of about 0.01. When I make 100 microliter injections of 2M NaOH, about 4-5 x the amount of contamination comes out, as quantified by peak area. BTW, all injections I speak of are made w/ a union in place of the column. I then did a little test in which I made 10 consecutive 100 microliter injections of 2M NaOH and the contamination peak area slowly decreased. This made me think that perhaps this contamination stuff can be washed out of the system. I just need to do enough injections of NaOH. So, I have set up my system to make 100 100 microliter injections of 6M NaOH.
My question is, is injecting 10mL of 6M NaOH in 0.1 mL increments going to damage either the 717 or the system (also Waters)?
Thanks,
Dave