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- Posts: 656
- Joined: Tue Jul 05, 2005 7:45 am
- Location: Denmark
Hi,
I was asked to look into analysis of free fatty acids in water solution (mainly lauric and mystiric acid). After some litterature search, I wanted to explore derivatisation and detection by RPLC-fluorescence
Before introducing any samples, I analysed standard solutions of lauric and mystiric acid in acetonitrile (1-10 µg/ml). The derivatisation was performed by adding PDAM reagent dissolved in acetonitrile at about 40 times molar excess.
At the 10 µg/ml fattyu acid concentration I got huge peaks. They were so high that I had to turn down the gain of the FL-detector to the lowest value and inject only a couple of µl to avoid detector overload. At the 1 µg/ml concentration I have a peak that is only 1/10000 of the area. The peak area of the 3 µg/ml solution is 10 times higher than the 1 µg/ml.
The LC method is just a quick water/acetonitrile gradient on a C8 column
Do any of you have an idea what is going on here?
I was asked to look into analysis of free fatty acids in water solution (mainly lauric and mystiric acid). After some litterature search, I wanted to explore derivatisation and detection by RPLC-fluorescence
Before introducing any samples, I analysed standard solutions of lauric and mystiric acid in acetonitrile (1-10 µg/ml). The derivatisation was performed by adding PDAM reagent dissolved in acetonitrile at about 40 times molar excess.
At the 10 µg/ml fattyu acid concentration I got huge peaks. They were so high that I had to turn down the gain of the FL-detector to the lowest value and inject only a couple of µl to avoid detector overload. At the 1 µg/ml concentration I have a peak that is only 1/10000 of the area. The peak area of the 3 µg/ml solution is 10 times higher than the 1 µg/ml.
The LC method is just a quick water/acetonitrile gradient on a C8 column
Do any of you have an idea what is going on here?
