Negative peaks using Normal phase

[liam1978]

Hi, Im getting na lot of negative peaks on my chromatography using a normal phase where I used to get positive peaks!!! This has happened before occassionally but it usually sorts itself out - is this a common occurrence with normal phase lc and why does it happen?????

[zokitano]

What kind of detection method are you using? What is the composition of your mobile phase? And what type of analytes you're analyzing?