-
- Posts: 85
- Joined: Wed Oct 19, 2011 9:46 am
Hey guys. I´m having a problem with ascorbic acid. I´m trying to do linearity with an HILIC method I´m developing. Kinetex HILIC 2.6 µm, 150 x 4.6 mm, MP Acetonitrile:Ammonium acetate buffer 50 mM pH 7.0 (90:10), injection volume 15 µL. Samples are in MP.
When I´m trying to do LOD-LOQ, 5% solution of sample concentration is not a high as it should, and sometimes even peak does not appear, it varies a lot. A 50 % solution does not show a great variation like 5% solution, but the same problema, is not as high as expected.
HPLC is working well. It is not a problem with injector, precision is good. Detector Works well, lamp is under 2000 hours and when you check it passes tests. Pump does not show any problem, no leaks or pressure fluctuation.
When I changed to another HPLC, happens the same.
I´m not familiar developing HILIC methods, Little experience with them, so I do not realise which problem I´m having. But I developed one for L-Cystine and had no problems.
Any ideas? Is it a method problem or vitamin C problem?
When I´m trying to do LOD-LOQ, 5% solution of sample concentration is not a high as it should, and sometimes even peak does not appear, it varies a lot. A 50 % solution does not show a great variation like 5% solution, but the same problema, is not as high as expected.
HPLC is working well. It is not a problem with injector, precision is good. Detector Works well, lamp is under 2000 hours and when you check it passes tests. Pump does not show any problem, no leaks or pressure fluctuation.
When I changed to another HPLC, happens the same.
I´m not familiar developing HILIC methods, Little experience with them, so I do not realise which problem I´m having. But I developed one for L-Cystine and had no problems.
Any ideas? Is it a method problem or vitamin C problem?
Q. F. Ignacio Viera
