By Vanessa Scholz on Thursday, June 17, 2004 - 05:21 am:

I´m from germany, sorry for my english.
I need help in an Analytical problem.
We want to know some komponets of very good naphthalin (ca 99%), so i want to meas those komponets via HPLC with DAD. Komponents are: organical N. In german: chinolin Iso-chinolin und chinaldin.
i think Quinolin und Quinaldin is it in english. can somebody help me?
I need a method.

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By Anonymous on Saturday, June 19, 2004 - 09:21 pm:

RP column, gradient, 40% acetonitrile to 80%acetonitrile. Look where peaks elute and optimize the solvent composition at the beginning and the end of the gradient.

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By Vanessa Scholz on Monday, June 21, 2004 - 05:31 am:

I say thank you, but i need to say, that i am very new in our laboratory, i never worked with hplc. so i need more informations. you say, 40% Acetonitril to gradient 80 % acetonitril, but which other solvent? Water or THF? (40% ACN : 60% THF?)and in which solvent can i put my sample to analyze(sorry for my english). wash with which solvent?

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By MG on Monday, June 21, 2004 - 06:59 am:

In reverse-phase (RP) HPLC, water is the weak solvent, to be mixed with a strong solvent (acetonitrile in the above recommendation). So you would start with 40% ACN : 60% H2O, and increase ACN during the run. You want to put your sample in your starting mobile phase (40% ACN), or a weaker solvent containing even less ACN and more H2O.