Negative baseline -105 mAU and cut peaks
Posted: Wed Oct 21, 2015 9:36 am
Dear all!
I have a problem of negative baseline and peaks cut by half (vertically) at the beginning and the end of each run.
I was doing a calibration test of Diclofenac Sodium salt, with concentrations 0, 1, 10, 20, 30, ... , 100 µg/mL. The solvent mixture was Acetonitrile:MilliQ 1:99 for the stock solution (300 µg/mL), then each vial consist of 400 µL of Acetonitrile and respective ratio of the stock solution and pure MilliQ (in order to have 1 mL in total in each vial).
The mobile phase is AcN:Water(+0.1% TFA) 40:60, flow rate 1 mL/min, inj.volume 100 µL, 280 nm, run time 40 min.
HPLC Shimadzu Prominence, UV-Vis, Ascentis® C18 HPLC Column (5 µm particle size, L × I.D. 15 cm × 4.6 mm).
This is how the chromatogram looks like:
I have a problem of negative baseline and peaks cut by half (vertically) at the beginning and the end of each run.
I was doing a calibration test of Diclofenac Sodium salt, with concentrations 0, 1, 10, 20, 30, ... , 100 µg/mL. The solvent mixture was Acetonitrile:MilliQ 1:99 for the stock solution (300 µg/mL), then each vial consist of 400 µL of Acetonitrile and respective ratio of the stock solution and pure MilliQ (in order to have 1 mL in total in each vial).
The mobile phase is AcN:Water(+0.1% TFA) 40:60, flow rate 1 mL/min, inj.volume 100 µL, 280 nm, run time 40 min.
HPLC Shimadzu Prominence, UV-Vis, Ascentis® C18 HPLC Column (5 µm particle size, L × I.D. 15 cm × 4.6 mm).
This is how the chromatogram looks like: