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Topic: retention time in HPLC  (Read 2460 times)

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Offline kriggy

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retention time in HPLC
« on: March 31, 2015, 12:17:51 PM »
Hi there, I was doing HPLC analysis of my reaction and question occured to me:
Is it possible that by changing method - specificaly mobile phase gradient - that peak of one compund change its retention time, while the other doesnt?
compound A: RT 1,04 in one gradient and 1,71 in second
compound B: RT 1,33 in one gradient and 1,31 in second

Ive seen that usualy both compound change their retention times but Ive never seen that only one does. I see no reason why this couldnt happen but it seems weird.

Thanks

Offline Arkcon

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Re: retention time in HPLC
« Reply #1 on: March 31, 2015, 12:53:10 PM »
Yes, that is possible to have.  You can even cause peaks tow switch positions, just by changing the gradient slope.  If you want to test such a thing out, look for a computer program called Drylab (and there are others) that will let you play with these sorts of experiments, without using up instrument time.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline kriggy

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Re: retention time in HPLC
« Reply #2 on: March 31, 2015, 02:23:35 PM »
Thanks its not that big of a deal, the MS and UV/VIS match so it is my compound, just the switch of the position of the peaks confused me

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