Dear Members,

I am running HPLC method for Abscisic Acid using water:ACN (75:25). When I use Sigma Aba standard, the peak appears at 19.2 min. After several injections, the peak shifts to 11.8 min. why this things happen?

when I run sample, there is only a small peak but the peak area is about 8 digit units. I surprise to see such a huge area for small peak. I have tried several time and several days but no improvement. Why this happen?

Regards