I advice u to post the chromatogram of ur compound and the parameters that u used so we could help u ?

The tailing indicates secondary interactions which are normally due to presence of free hydroxyl groups in stationary phase. Its better to move on RP-18 Column with end-capping.

otherwise increase formic acid or use acetic acid in mobile phase.

Hello

Thank you for the prompt response, my chromatogram shows a peak tailing at the end ,the peak shape is nice and sharp in the beginning but it tails towards the end.

I am using only 0.1% formic acid and i tried the acetic acid 0.5% and 5% as well but still there is tailing.

I thought i can buffer the system with ammonium formate at PH 2-3, but i will give it a try to increase the concentration of formic acid in water and see what would happen.

Thank you again.

mail me the chromatogram and its conditions 

Maybe you can increase the  formic acid percentage, from 0.1% to 0.2% or 0.5%, take a try, or you can change a organic acid column, this column is very powerfull for acid seperation.

How old is your column ? 

I completely agree to Mr. Syed Tariq Ali. this will surely resolve your problem

1-try to use 0.05%of hexane sulfonic acid sodium salt with amm. acetate buffer pH 3

2- try to use TFA 0.05%

with ACN

My column is one month old it is a new column but it started giving the tailing from the first day.

Than you for the answers i will try those options and see.

Hi, Chahinez Houacine

I was also facing same problem i have resolved that by Using C8 column with 150 mm. and Phosphate buffer 0.05M with 0.1% TEA and pH 6.5. You can also try that .

 Hi Chahinez Houacine,

The tailing effect is due to the interaction of free silanol group with the hydroxyl group present on your molecule. (Dipole-Dipole interaction)

As you are using 0.1% Formic acid in your mobile phase, your are no left with addition of mobile phase modifier.

Suggestion,

1. Try to use a column which has an endcapping to it.

2. Try with the different mobile phase containing 0.5 % OPA and then try using TEA as a peak modifier, you will definitely get the positive result.

Please revert with your results

Try citrate/methanol based mobile phase.

 Hi Chahinez Houacine,

In addition to the earlier post, if you are developing method for LC-MS then try using organic buffer. As the inorganic buffer has some problem in MS detection.

Also there are some column like Zorbax XDB C18, Xterra RP C-18 which can give you good peak shape.

Hi,

I increased the formic acid concentration to 0.5 %  and i already used acetic acid 0.5% but the column shows a low reproducibility every time it gives different  symmetry value.

I also tried different columns and endcapped column as well but tailing is still there.

Any suggestions

Hi Chahinez Houacine,

I think things are getting much more complicated.

Can you give some information on.

1. pKa for your drug.

2. Chromatographic parameters.

3. What is the purpose of this Analytical method.

And also please provide the data on Peak tailing, Peak RT and Theoretical plates.

Eagerly waiting for your reply..

Agree with above mentioned posts. You need to explore the columns that are suitable for your compounds. You can call the company and ask for technical suggestions, what can be useful too. I know that Phenomenex offers a demo column for trial.

• Hi,

My drug pka strongest acidic(8.99) and strongest basic (-5.77)

Hplc method was using gradient system A was acetonitrile and system B was 0.5% formic acid in water, the gradient is as follows:

time (mints)      A             B

0                        50            50

10                      90            10

I used 15 papers method of course they are using different column brands but same dimensions , that should work if their methods is reproducible but nothing worked for me.

I am developing a method for my drug with the HPLC.

Thank you

Your gradient is not usual, maybe its good for you to read a bit about basics chromatography. Using the existing "gradient" the column doesnt retain the compound, does it? 

You may want to try using the mobile phase that Andrew suggested in above post. Try a very slow ramp and have a longer run time. Experiment with the composition of the mobile phase. Let us know how you go

Hi

From the given data it seems that at the given mobile phase pH, the compounds remains very non polar and that is the reason you need high organic for the elution. 

Have u tried on other pH of your mobile phase?

Just try using 15mM ammonium acetate or ammonium formate in your mobile phase with pH about 4.5- 5.0 and see the retention behavior. 

as you go high on pH, the silanol activity will reduced and you will get a good peak shape. Try to use a column which will have less silanol activity.

Are you developing a method for LC-MS or and related substances method?

As Maria said your gradient is very unusual. try not to use a steep gradient..

waiting for your results