Newsgroup sci.techniques.mass-spec 1187

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To whom it may concern,
My name is Eric Nordstrom.  I am a Nondestructive Inspection Specialist
within the U.S. Air Force.  This note is designed to notify individuals
within the Nondestructive Community that I have a homepage posted designed
to allow easy access to hard-to-find information, other web sites,
newsgroups, and employment all Nondestructive Oriented. 
Please pay a visit to "http://netnow.micron.net/~dozod/".  Send me
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Thank you,
E.G.Nordstrom

Brodifacoum can be detected quite nicely by positive ion APCI using an
acetonitrile/water gradient. Use a C18 column and add 0.1 % formic acid to
moble phase to suppress ionization of the acidic enol group.  Tandem MS
on MH+ ion is quite useful for i.d. proof.
regards,
rick flurer
phil harris  wrote in article
<59e6q3$c34@acmey.gatech.edu>...
} Im trying to set up an LC-MS method for the analysis of a rat poison 
} (brodifacoum) but have found that in ESI the chromatogram is inverted ie 
} the analyte apparently suppresses the background ion current.  The 
} effect is the same in positive and negative mode, and I havent tried 
} APCI yet to see if the effect is the same.  Is there a way around this 
} to get my chromatograms the right way up?!
} 
} 
} 
} 
} 

In the process of investigating the fatty acid synthesis pathway of
bacteria I was forced to synthesize 3-Hydroxy-Decynoyl NAC(ie you might
not be able to buy it)  I am pretty sure that the enzyme pathways are
stereospecific for one isomer over another.
The Cycle of FA synthesis produces the 3-0H configuration .  This is
stereospecific in E.Coli (and most others I'd imagine)Because the
subsequent step in which the 3-OH form is utilized has a stereospecific
requirement.
I Quote;
Beta-Ketoacyl-ACP reductase
The reaction product of acetoacetyl-ACP has the D(-) configuration.
Beta-Hydroxyacyl-ACP dehydrasae
The enzyme (beta-hydroxyacyl-ACP dehydrase) catalyses the dehydration of
D(-)-beta-hydroxyacyl-ACP thioesters to form trans-2-enoyl-ACP
thioesters...
Like the beta-ketoacyl-ACP synthetase, the dehydrase has an absolute
specificity for thioesters of ACP; it is inactive with thioesters of CoA
or pantetheine.  The reaction is stereospecific; the D(-) isomer of
beta-hydroxybutryl-ACP was dehydrated whereas the L(+) isomer was not.
pg 123
Quotes from 
Biochemistry of Lipids
Ed. TW Goodwin, F.R.S.
Vol. 4 of the MTP International Review of Science Series
1974
ISBN 0-8391-1043-X
Butterworth and Co. Pub.
You might also check out Morris Kates' "techniques of lipidology" Elsevier
(2nd ed 1986)
This guy is the GOD of lipids in my opinion.
he says on pg 34
"The b-hydroxy saturated acids form a series of even-carbon
acids...3-Hydroxy acids are fairly widespread in yeasts and bacteria,
usually occuring as D(-) isomers in ester bound or glycosidic forms in
extracellular lipids.  For example, 3-D-OH-C10,-C12,-C14 acids are
constituents of lippopolysaccharides in cell walls of Gram-Negative
Bacteria (Kaneshiro & Marr 1963 Biochim.Biophys.Acta, 70,271);
3-D-hydroxy-C10 acid occurs in the rhamno-lipid of Pseudomonas aeruginosa
(Jarvis and Johnson 1949, JACS, 71,4124)...(another ref...Tulloch and
Spencer1964, Can.J.Chem.42,830)..The D-3-OH acids are also intermediates
in the beta-oxidation pathway of fatty acids."
 Many people (eg. Julie Leary et al) have been using the addition of 
Metals to differentiate  various types of isomers using mass spec.  If you
have some standards in D and L forms and you have a mass spec you could
develop a method.  Otherwise maybe one of the old papers have methods
(bucket loads of sample ?)  Source of the material combined with
literature info may tell you indirectly the D/L of what you have.  John
Cronan is another awesome lipid guy (U Ill ?)
good luck
Matt Sweeney
good luck

You might try putting it on a column and seeing what the chromatographic
profile of the contaminant versus the peptide is.  It'd give you some
clues.  It'd also get the peptide away form the garbage.  (a guess >>> 
Mannitol/Inositol +Na = 203.2 ?)

has anyone had any luck with amine analysis
using mass spec?
any advice would be appreciated.
pete