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Topic: hplc graph help  (Read 3659 times)

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Offline 2cats39

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hplc graph help
« on: June 20, 2011, 10:15:35 AM »
hey, ive just done a hplc experiment about the amount of nictotine in fags. i have a standard and my actual sample on two seperate graphs. but i also did another standard which was also in my sample. problem is they are just graphs to me. i think i have to work out how much difference there is in the standard and in my sample. but i have no idea where to start please help xx i would like to know how to anaylyse my results and possibly any equations if they are needed as i assume it is not as easy as just comparing the peak areas although my idea was to possibly compare the lutodine standard and peak in my sample and find the difference and then that will some how factor in to the comparison of the intcine peaks if you know what i mean. please help thanks. xx

Offline fledarmus

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Re: hplc graph help
« Reply #1 on: June 20, 2011, 10:41:04 AM »
The normal way of doing this is to prepare a standard curve: take your standard and prepare a series of standard dilutions, running each dilution on the HPLC and graphing the (known) amount of nicotine in the sample and the (measured) area under the curve on the HPLC trace. When you run your unknown sample, you should be able to measure the area under the curve, find that point on your standard curve, and it will tell you the amount of nicotine in the sample.

Offline 2cats39

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Re: hplc graph help
« Reply #2 on: June 20, 2011, 11:18:06 AM »
i have already done the practical and this is definately what i was suppposed to do and its worked pretty well i think. i have the exact same retention times in my standard as i do in my sample (along with alot of other peaks due to the major amount of crap in cigarettes)

Offline fledarmus

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Re: hplc graph help
« Reply #3 on: June 20, 2011, 01:06:36 PM »
Good! Then if all you are interested in is the amount of nicotine in the cigarette, you can isolate that peak, measure the area under the curve, and compare it to your standard curve to find the actual amount present.

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