LC-MS/MS method for polar compounds

[pramodkollu]

Hi All,
I got 3 analytes (no structures provided) with little information. Compounds similar to Cytidine monophosphate and one unphosphorylated. Trying to get a LC-MS method for quantitation in biological matrices. Due to polar nature of the compounds, there is no retention of phosphorylated analytes on a regular C18 columns. Do I need to go with ion-pairing chromatography, which I'm trying to avoid if at all possible. I believe the monophosphate is polar acidic compound. Is HILIC an option here? Any suggestions please - Thanks!

[yellaiah2013]

bisphosphonate,monophosphonate are not ionise in MS/MS due to their High polarity.eg.Risedronate.
So we should go for derivatives method.
After derivative their molecular weights and properties are chanhed and ionise in MS/MS.

[JMB]

bisphosphonate,monophosphonate are not ionise in MS/MS due to their High polarity.eg.Risedronate.
So we should go for derivatives method.
After derivative their molecular weights and properties are chanhed and ionise in MS/MS.

This is not correct; phosphonates are detectable by ESI-MS in the negative ionization mode.

[jenche]

Hi All,
I got 3 analytes (no structures provided) with little information. Compounds similar to Cytidine monophosphate and one unphosphorylated. Trying to get a LC-MS method for quantitation in biological matrices. Due to polar nature of the compounds, there is no retention of phosphorylated analytes on a regular C18 columns. Do I need to go with ion-pairing chromatography, which I'm trying to avoid if at all possible. I believe the monophosphate is polar acidic compound. Is HILIC an option here? Any suggestions please - Thanks!

HILIC might help you. There are some papers/application note that might help you :

• http://www.ncbi.nlm.nih.gov/pubmed/22816250
• http://www.merckmillipore.com/showbrochure/201008.054.ProNet.pdf

[pigfarmer]

From my experience you can separate phosphonucleotides on a C18 column (AMP/ADP/ATP) with just isocratic flow rate with say, phosphate buffer.

[ddjchemist]

It might not be possible to accurately analyze those compounds in their pure form (without derivatization). The reason is that they are highly polar and they get accumulated on stainless steel (you can find many articles about this topic). Almost everyone neglects this fact.

Good Luck,
Dan