By Anonymous on Tuesday, March 30, 2004 - 09:18 pm:
I analyzed an aromatic amine hydrochloride salts using HPLC. But what I found was that the compound gives two peaks with same UV spectra.
Also I tried in LC-MS method where the two peaks gives same molecular weight. It is a reverse phase method and the analysis was carried out in acidic medium. Why it gives two peaks in HPLC?.
By mokhtar on Tuesday, March 30, 2004 - 11:33 pm:
1- what was the retention times for the two peaks?
2- are you sure that your compound is pure?
3- Do you dissolve the samples in mobile phase or in another solvent?
By Anonymous on Wednesday, March 31, 2004 - 03:01 am:
1. The retention times for the two peaks are 2.3 and 2.5 and purity % 25 and 75 respectively.
Both are giving Same mass and same UV spectra.
2. The compound is pure only
3. Dissolved in mobile phase
By RH on Wednesday, March 31, 2004 - 03:23 am:
If Your compound is really pure, peak splitting can happen because of a void volume at the column head or disturbed packing or by a clogged inlet frit. You can check this by injecting different compounds that will, in case of a column problem, should result in split peaks.
Furthermore you can try to inject your sample in a solvent weaker than the mobile phase.
By Anonymous on Wednesday, March 31, 2004 - 05:12 am:
The column works fine for other compounds and no splitting.
By Anonymous on Wednesday, March 31, 2004 - 07:54 am:
The cpds might have several isomer forms. Try the analysis at elevated temperature and see if there is only one peak.
By Anonymous on Wednesday, March 31, 2004 - 10:14 am:
Your amine salt and mobile phase heve different acids, you should try to dissolve your sample in the mobile phase and see what happened when you inject it
By Anonymous on Thursday, April 1, 2004 - 08:00 pm:
Is it due to the formation of two different amine salts or presence of free amine along with amine hydrochloride salts?
By Anonymous on Tuesday, April 6, 2004 - 06:40 am:
We faced the same problem in our lab. Our method is isocratic 0.1% TFA : ACN (95:5)on waters Symmetry C18. The two peaks for Pramipexole HCL tablet were obtained at 3 and 6 mins when the tablet was dissolved in water or water-ACN mixture. When the same sample was prepared in 0.1% TFA we got a single peak at 6 mins
By Anonymous on Thursday, June 3, 2004 - 03:29 pm:
You apparently are not using a buffer for analysis of your hydrochloride, or your buffer capacity is not enough to neutralize the hydrochloride during HPLC. Basically, you have an uneven pH profile during your HPLC run with a pH dictated by the hydrochloride rather than a buffer inside of your peak maximum. This leads to a partial split of the peak. Try using higher buffer concentration or reduce the amount of your hydrochloride per an injection, or do both.