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- Posts: 26
- Joined: Wed Jun 05, 2019 3:57 pm
I'm noticing a strange behaviour from my HPLC when I inject the same sample repeatedly.
I have my system calibrated with know standards at:
0.1 ppm
0.2 ppm
0.3 ppm
0.4 ppm
0.5 ppm
The calibration is very accurate and gives good results.
However, when I run any sample, for example I did my 0.3ppm today, repeatedly, my results vary.
Real results from today:
0.3ppm calibration result = 0.3098ppm
But when I run this sample 3 times, I get the following:
1: 0.3020 ppm
2: 0.2910 ppm
3: 0.2830 ppm
If I continue, the sample gets lower and lower. Even if I do sample > blank > sample > blank, the results are the same.
Can anybody offer any input? Thankful for any help at all.