THC retention time shift

[fredindose]

Hi All, first post. We ran a cerilliant delta-9 THC on a shimadzu HPLC and got a retention time of 2.88 min. We then went to run our sample, which is a puff of vapor from when you vaporize cannabis oil concentrate. That came out at 3.21 min. We isolate the puff by mixing with MeOH for a few min. Any clues about what might be going on? We ran thru QQQ-MS, and saw our puff had a mass of 313, whereas the standard had 315.. could it be chemically altered in the syringe? During vaporization/atomization? What is up? Best,

Confused THC

[Consumer Products Guy]

I wonder if your standard is made up in methanol as well, or is the issue that your standard and sample are in different solvents - you may have the solvent injection effect happening here.

I'd start by injecting half the amount, seeing if the issue disappears. Second I'd try a different solvent for the sample, or maybe diluting it 1:1 with water.

[fredindose]

They were all in Methanol. But I went back to the lab a few days later with new/fresh samples to test and our issue went away. The new thing we are facing is the weird results we get at different wavelengths, and other stuff that is in our vapor. Please refer to my new post, thanks so much for your help.