Re: LC-MS of Non - Polar compounds

Hi Richard,

use composition and concentration similar to the original literature (for
references please e-mail me at the address below) and T-in the silver salt
solution post-column. With a robust ion source, as the Sciex source is, you
can work with it without too much worries and even change back to normal
conditions afterwards.  Nevertheless, for quantitation of large amounts of
samples I propose to T-in the eluent and switch to the Ag-solution only
during the time window of the eluting compound of interest. Whether your
compounds do form Ag-adducts and what optimum ms conditions for the adducts
are can more easily be tested starting with infusion.

In my experience it is better to avoid adduct formation but despite vendors
using the classifications gold and platinum to describe their most sensitive
triple quad systems, silver seems better for quantitation.

Regards,

Peter Jacobs
NV Organon 
Pharmacology - Bioanalysis
Oss, The Netherlands

[EMAIL PROTECTED]




> From: "Honeywell, R." <[EMAIL PROTECTED]>
> Organization: *
> Newsgroups: sci.techniques.mass-spec
> Date: Tue, 11 Nov 2003 09:33:50 +0100
> Subject: LC-MS of Non - Polar compounds
> 
> Dear All
> 
> I am having a difficulty with a steriod-like molecule which doesn't want to
> Ionise at all in the interface. I have tried both turboion spray and APCI at
> a variety of conditions but I only see a minimal response. I have heard that
> if I use silver solution chemistry I can generate ions from non-polar
> molecules with a reasonable sensitivty. I have never set this up before and
> was wondering if anybody had some practical experience with this techique so
> I do not have to "re-invent the wheel" as it were. I have some technical
> references but few pratical details, if anybody knows a good reference
> source I would be grateful.
> 
> regards
> 
> Richard Honeywell
> VUMC Amsterdam
> Department of Oncology
> de Boelelaan 1117
> 1081 HV
> Amsterdam
> The Netherlands
> 
>