If compounds are basic you can add 0.1 % of diethyl amine. If they are acidic then you can add 0.1 % trifluoroacetic acid. Both will prevent tailing by avoiding interaction with free OH in the stationary phase.

I hope it helps

If compounds are basic you can add 0.1 % of diethyl amine. If they are acidic then you can add 0.1 % trifluoroacetic acid. Both will prevent tailing by avoiding interaction with free OH in the stationary phase.

I hope it helps

Try cleaning the guard column and increasing the flow rate through the column. Also try degassing the mobile phase for a longer time if you are already doing it.

I hope it helps.

What Marcelo said! Also, how long is your C-18 column?

I agree with Marcelo. Make sure the concentration of your sample isn't too high, that can also cause tailing. If you can try using a gradient separation, this too can reduce tailing.

If your molecule is ionic , you can try ion pair agent

I agree with Marcelo and Sinéad. Also I hope that the suggestions gave good results.

Marcelo offers some good advice. You can also add concentrated salt (ammonium acetate for basic) to the sample itself. Just account for the volumes in your concentration data!

The best way to reduce tailing is that you should decrease the sample concentration. Also you can use a low concentration of ion pair agent like SDS.

Try to use end-capped columns if adding Triethyl or trimethyl amines didn't improve peak shape.

Agree of all above, but try to find pKa of your drugs and buffer mobile phase. Establish the pH of mobile phase (or the buffers) as the pKa or in pH where the drugs have molecular forms.

If you use precolumn, try to inject without it

You should be sure that,

1-Your column is cleaned and working well(The simplest way is to examine the column performance according to "shipping inspection criteria" in the column inspection report attached to the column.)

2-Your sample is prepared and degassed well.

3-Equilibration time (length of column*2).

if the same occur try TEA or TFAA as Marcelo Muñoz said.

In addition I find that in general gradient elution methods give better peak shapes particularly with respect to peak tailing. Use an acetonitrile gradient.

The first and foremost point to reduce tailing effect is the choice of class B silica based columns like Purospher STAR (offered by MerckMillipore) .This chemistry is polymeric resulting into complete coverage of free silanols on the surface of silica allowing highest hydrophobicity for retention.

Second factor is to reduce water (alongwith buffer) part and increase solvent part for better sensitivity and less peak width.

Third parameter can be working at high temp. above room temp.

I also found some discussions showing use of ion pairs if the compound is ionic in nature,that means the compound is soluble in water and then the choice of HPLC column will also come into picture,ZIC-HILIC/ZIC-c HILIC columns from MerckMillipore offers opportunity to avoid ion pairs and at the same time offers opportunity to work in RP mode.

In the following link you will find a very useful information regarding peak shape in HPLC

https://www.chem.agilent.com/Library/eseminars/Public/secrets%20of%20good%20peak%20shape%20in%20hplc.pdf

Also in the following link you will find a very useful information regarding peaks tailing in HPLC: http://www.chromatographyonline.com/lcgc/data/articlestandard//lcgceurope/382003/69793/article.pdf Adding of triethyl amines could help You, but be carefull, because they used to stay in HPLC system for long time, You have to wash them properly..

I agree with all other suggestions and you try MOBLE PHASE with low concentration of TEA and THF that can help to reduce peak tailing. you need to check the pka of your compounds to choose suitable moblephase.

Peak tailing due to

The flow-line contains extra dead volume

Some basic or chelating compounds show singular tendency to adsorb to stationary phase

(Remedy: suppress absorbance by adjusting the separation conditions, such as mobile phase pH, etc.)

Sample overloading

Silica-based column degraded at high pH or high temperature

hope this may help

In addition to what other suggestions, you can also decrease the pH of mobile phase(less than the pKa of your analyte).

I proposed to read attached files

I am using TEA because my compound is basic, still I have tailing and broad peak. I changed many columns and with ODS Phenomenex column tailing is the least but I do have tailing left. Anything else to try?

First check pKa value for your analyte. If analyte pKa and your mobile pH value is same, analyte is 50% ionized and 50% nutral so it can be elute with tailing. So mobile phase pH should away from +/- 2 from pKa. If Acid or base is not helpful use buffer.

Also try C8 , Phenyl column. 

Dear All

what is the suitable mobile phase for Carbofuran and its intermediates

Regards,

To avoid peak tailing due to secundary interactions in reversed phase chromatography, two possibilities: adding trimethyl amine or using an end capped column.

Hi, 

Tailing could be due to a number of factors including column failure or inappropriate analytical conditions.

You can check the column performance by running a simple test mix with compounds you know will give good chromatography (or repeating the one supplied with the column).  Tailing peaks can be an indication of a void in the column or contamination of the inlet frit.  If contamination, you may be able to improve by washing with solvent(s) eg high % organic.

Tailing can occur if you are working at the wrong pH with ionisable compounds.  You need to be (ideally) 2 pH units away from the pKa of your compound.  For acids this is 2 units below eg if compound pKa is 4.5 then mobile phase should be pH 2.5.  For bases you should be 2 units above.

It can also be due to interactions of your compound with silanols on the stationary phase.  Try adding a small amount of base or acid (or both) or alternatively try a different stationary phase that is better end-capped.

Overloading can cause poor peak shape (try reducing the concentration of sample or using a smaller injection volume) and ideally inject your sample dissolved in mobile phase solvent (or a solvent containing a higher percentage of water than your mobile phase).

Hope this helps.

Phil

Need to think about mode of sample injection.

Check your column guide about how much sample and volume you can inject.  Too much sample or too much volume  may cause problems 

It is highly necessary to look at column selection criteria - Class B silica columns like Purospher STAR from Merck  or base deactivated silica packed columns like LiChrospher RP Select B are highly recommended.

In case of Mobile phase addition of addition of modifiers based on pH e.g. TFA or Triethyl amine etc.

Injection volume or concentration of analyte to be optimised

Column dimensions can be reduced to smaller I.d. like 4 or 3 mm if the molecule has tendency to tailing.

the firts, the peaks arent tailing, but now it is tailing. i analysis leaf sample

Qui Trần , did you ever resolve your issue? I would imagine something in your sample is accumulating on the stationary phase and changing its chemistry. Maybe you need a more thorough wash after each sample.

It can be a lot of things. Check the concentration of the sample, injection volume, solvent you are using to prepare your sample, cycle time and scan time if using MS, all the fitings and tubings and finally the column. Hope you were able to solve this problem.