By Cindy on Wednesday, November 6, 2002 - 01:44 pm:
Does anybody know a good LC/MS method or LC method for Calixarene? Calixarene has a molecular weight of 992.5. This compound sticks on any reverse phase columns and it is hard to clean the columns.
Cindy
By Anonymous on Thursday, November 7, 2002 - 09:08 am:
Have you considered normal phase?
By Cindy on Thursday, November 7, 2002 - 10:19 am:
Normal phase usually uses none polor solvents. These solvents are usually not good solvents for ESI-MS. If I can not find a good reverse phase method I will try normal phase. Thanks.
Cindy
By M on Thursday, November 7, 2002 - 11:25 am:
I searched in a couple of places and found this article. I don't know much about the chemistry you are doing but I hope it is of use to you.
Optical resolution of phosphorus containing calix[4]arenes by additive RP HPLC method.
Kalchenko OI, Tairov MO, Vysotsky MO, Lipkowski J, Kalchenko VI.
Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya, 5 553660, Kiev-94, Ukraine.
The RP HPLC method (LiChrosorb RP18 or Separon SGX C18 column, acetonitrile-water 86:14 v/v mobile phase) was applied for enantiomeric separation of topologically chiral 5-bromo-25,26-bis(diethoxyphosphoryl)calix[4]arene 9 or 25-ethyl-26-dihydroxyphosphoryl-calix[4]arene 5. Separation of calixarene 9 was achieved by the addition of D-(-)-tartaric acid which formed hydrogen bonded diastereomeric associates with 9 to the mobile phase. Calixarenephosphoric acid 5 was transformed into diastereomeric salt 6 by addition of L-(-)-alpha-phenylethylamine before RP HPLC separation.
Good Luck,
Melissa
By Anonymous on Friday, November 8, 2002 - 06:49 am:
If you find yourself using normal phase, you should use APCI for an ionization technique, it works quite well. Two precautions for normal phase work with APCI though: Be sure that you have adequate ventilation for exhaust from the MS source, and don't run out of nitrogen when the MS is operating.
By Cindy on Friday, November 8, 2002 - 07:55 am:
Thanks for helping. I tried APCi yesterday and I got good signal from the mass spec. I have not tried normal phase yet. The column I ordered is taking a while to get to me.
Cindy
By sanjay on Sunday, December 1, 2002 - 03:26 am:
Does any body have the Stability indicating method for the Naproxen BP
We like to have the mathod for the stability Assay and related substance for Naproxen Tablet 250mg and 500mg
Posting is currently disabled in this topic. Contact your discussion moderator for more information.