P A B cyclodextrin in Waters Setup solution

[bunnahabhain]

Hi everybody

We baught a used Quattro Ultima here in our lab. For instrument qualification I want to mix the standards on my own (no need to pay quite a lot of money for the certified standard solutions, an analytical balance and the substances will do for me). However, there is one subtance I am not sure about: What is "P A B cyclodextrin"? It is mentioned in a document called "Waters MS Systems Qualification Workbook". Is it Triacetyl-beta-cyclodextrin? I found this as component in http://www.waters.com/waters/partDetail ... =700002646, but the mass that is to be monitored according to the qualification tests is [M+H]+ = 2034.6 Da while the monoisotopic mass of Triacetyl-b-cyclodextrin is 2017.7.
Any help?

Thanks a lot
Jörg

[JMB]

The m/z 17 difference suggests that the qualification ion is [M+NH3+H]+; is the analyte injected in an NH4OAc solution ?

[bunnahabhain]

Hello JMB

Yes, there is 4 mM NH4Ac in the setup solution. Thank you for the hint. But I still don't understand the "P A" in the subtance name...

Jörg

[JMB]

P A = per-acetyl, i.e. fully acetylated.

There are 7 glucose rings in beta-cyclodextrin (monoisotopic mass = 1134.4 Da), and each ring has 3 free -OH groups that can be acetylated = 21 acetyls total.

Monoisotopic mass = 1134.4 + (21 x CH3CO)-(21 x H) = 2016.4 Da