Hello from Tepui's Land: VENEZUELA!
I'm looking for a method to detect Phospholipids in Human
Amniotic Fluid by Chromatographic or Electrophoretic method.
Thanks in advance,
Ruben Cortez
Is anyone going to this lipid course in Italy in a couple of weeks ?
http://www.cmns.mnegri.it/en/congres/Febs2000/html/index.html
June 21-26, 2001 [Fri - Tue inclusive with evening registration on
Thursday 21st and welcome dinner.]
Consorzio Mario Negri Sud,
Santa Maria Imbaro (Chieti), Italy
The conference plus accommodation costs ~£270 GBP (440 € / 850,000 IL)
and I've put the registration form on the lipids website, which
can be found at : http://groups.yahoo.com/group/lipids/files/
FormsFEBS.pdf = booking form
transport.pdf = your arrival and departure times / dates so that a bus
can pick you up and return you to airports / train stn.
RyanAir appears to be offering cheap fares to Pescara (a nearby airport)
but it would seem that booking before midnight on Monday is necessary
to ensure the lowest fares.
I only found out about this course today - if anyone already knew about
it can they tell me where they heard about it as perhaps I should be
subscribing to that mailing list as well ! ;)
Maybe see some of you there,
Jo
Hello everyone,
I've inherited a 10mg vial of dipalmitoyl phosphatidylserine
[Sigma P 1185] which I thought I'd run through my solid phase
extraction protocol to test recovery of phospholipids.
As it's a sodium salt, I'm wondering if its retention on my
diol SPE columns will be different from tissue-extracted
phospholipids and if I'd have to modify the procedure to elute it.
I hope it's not too banal a question, but I'm one step removed
from phospholipids since I work on diacylglycerols !
Apologies to those receiving this message twice, as I've posted
it to the phospholipids mailing list.
Thank you
Jo Brodie
p.s. the SPE method is a modification of the Kaluzny 1985 method,
using diol instead of aminopropyl columns to minimise isomerisation
of diacylglycerols [Pacheco 1998], I just thought it would be
interesting to check recovery of a known phospholipid as well.
Journal: Journal of Chromatography A
ISSN : 0021-9673
Volume : 917
Issue : 1-2
Date : 11-May-2001
pp 239-244
Pressurized liquid extraction of lipids for the determination of oxysterols
in egg-containing food
E. Boselli, V. Velazco, M. Fiorenza Caboni, G. Lercker
pp 251-260
Structural analysis of commercial ceramides by gas chromatography-mass
spectrometry
J. Bleton, K. Gaudin, P. Chaminade, S. Goursaud, A. Baillet, A. Tchapla,
Groupe de Chimie Analytique de Paris-Sud
Visit the journal at http://www.elsevier.nl/locate/jnlnr/05158
Jo
If anyone can help with this query, please respond directly to
Eva at this email address : evarguez@...
Thanks,
Jo
___________________________________________________________
My name is Eva and I'm a PhD student from the University of
Extremadura (Spain). The subject of my thesis is the anaerobic
treatment of wastewater generated in destilleries for alcohol
production.
At the present moment I'm engaged in finding a feasible method
for the quantitative and qualitative analysis of volatile fatty
acids present in this type of effluents.
I would really apreciate if you could let me know the best method
to be used for this purpose, taking into account that the waste
water to be analyzed contains a high organic load. I believe that
the presence of high amount of organic substances might constitute
a serious drawback when using chromatographic techniques.
Should I get the methyl esters of VFA and use a head space device?
Is there any extraction method to avoid all the aforementioned
problems?
It would be helpful any information regarding this matter.
Looking forward to hearing from you. Thanks in advance.
Sincerely yours
Eva.
Eva Rodriguez Franco
Dept. of Chemical Engineering
University of Extremadura
Avda Elvas S/N , Badajoz
Spain.
I have copied /forwarded this post, which was sent to
the Start GC! forum - as Nick isn't subscribed to the
lipids list, if anyone has any help to offer, please
contact him directly at : huemmer.2@...
Thanks, Jo
p.s. Start GC! can be found at :
http://members.kr.inter.net/guesu/startgc/page/forum/forumlist.html
Author: Nick Huemmer 02/08/2001 03:16 AM
Subject: How to quantify cyclopropane fatty acids from the
bacterial membranes
I am trying to isolate and quantify cyclopropane fatty acids from the
outer membranes of lactic acid bacteria, (mainly C19, methyl
dehydrosterculate and methyl lactobacillate). My group is trying to
find a column and conditions that would be best suited for this
purpose.
Is there anyone out there that has experience with this sort of work
and can help steer me in the right direction? Any input would be
greatly appreciated.
Nick Huemmer
From the plant lipids mailing list...
------------- Begin Forwarded Message -------------
Date: Tue, 23 Jan 2001 11:13:04 -0500
From: Jan Jaworski <jaworsjg@...>
To: NPLC-L@...
Subject: Postdocs available
Postdoctoral positions are available immediately to study the
production of unusual fatty acids in oilseeds. A Ph.D. with a strong
background in biochemistry and molecular biology is a minimum
requirement, and experience with plants and plant molecular genetics
is highly desirable. A functional genomic approach to understanding
lipid pathways leading to the synthesis of unusual fatty acids will
be a major focus of the research. These projects are part of a
multidisciplinary collaborative effort to produce industrial feed
stocks in agronomically important crops. This research will be
carried out at Miami University in Oxford, OH located in the
southwest corner of Ohio. Please send a curriculum vitae (preferably
by e-mail) and contact information for three references to Jan
Jaworski, Department of Chemistry and Biochemistry, Miami University,
Oxford, OH 45056. E-mail to jaworsjg@....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jan Jaworski, Professor
Dept. of Chemistry and Biochemistry
Miami University
High St/ Rm 243 Hughes
Oxford, Ohio 45056
phone: (513)529-2094
FAX: (513)529-5715
e-mail: jaworsjg@...
-------------- End Forwarded Message --------------
I will inforrm all surfers interested in lipid science that the
Cyberlipid Center has now its own domain name you can use to have a
direct access to the site:
www.cyberlipid.org
The previous one (http://go.to/cyberlipid) will work yet for some time.
Dr Claude Leray
[Non-text portions of this message have been removed]
Hi,
My first port of call would be Claude Leray's
excellent Cyberlipid website which has many
protocols and references for lipids.
The 'front page' address is :
http://go.to/cyberlipid - which you can then
search and view pages in frames.
Here is a page on the analysis of ceramides :
http://pulsix-w.sdv.fr/cyberlipid/ceramt/cera0001.htm
On another page there is an HPLC chromatogram with details
showing how sphingomyelin was resolved from PE, PS... PI
etc. as a single band.
http://pulsix-w.sdv.fr/cyberlipid/phlipt/pl40004.htm
For general interest purposes, there are a few links
at the egroups site :
http://www.egroups.com/links/lipids/
Scroll down and click on 'Types of Lipids' and then
on 'Ceramides'.
Next, I'd visit The Lipid Analysis Unit at:
http://www.lipid.co.uk
and search their library of articles for sphingomyelin
and ceramides - both words crop up in this page which
is a selection of references of phospholipid analysis :
http://www.lipid.co.uk/infores/lit_surv.html
Also, I might get in touch with cosmetic companies
and ask for assistance as they certainly use ceramides
in such products (it is often used as a selling point !).
Hope that helps
Jo
p.s. if you find any other useful ceramide sites that
you think should be on the links page, tell me and I'll
add them, or feel free to add them yourself.
Hello:
does somebody have a working HPLC method to analyze
sphingomyelin and it's derivatives (notably
ceramide?). We have a very sensitive ELSD detector, and
several normal- and reversed-phase columns. I could not find a
decent method on medline.
I also would consider using thin-layer chromatography, provided
there is a method to quantify non-phosphate containing lipids.
Maybe somebody knows how to derivatise ceramide? Any help
would be greatly appreciated!
Erik Eckhardt, Ph.D.
------------- Begin Forwarded Message -------------
Date: Wed, 17 Jan 2001 14:44:15 -0500
From: Kim Traylor <traylokk@...>
To: NPLC2001@...
Subject: NPLC Announcement
Dear Plant Lipid Researchers: Below is information on the fourth NPLC
meeting at Lake Tahoe. This information (and more) will also be
available at the NPLC WWW site: http://www.msu.edu/user/ohlrogge/ You may
find it convenient to send applications and abstracts from this WWW
site. Some aspects of this WWW site are still under development.
SECOND ANNOUNCEMENT: 2001 SYMPOSIUM ON BIOCHEMISTRY AND MOLECULAR BIOLOGY
OF PLANT FATTY ACIDS AND GLYCEROLIPIDS.
June 6-10, 2001 (Wednesday - Sunday)
Sierra Camp at Fallen Leaf Lake
South Lake Tahoe, California.
Plenary Speakers:
Jonathon Napier
University of Bristol
Christoph Benning
Michigan State University
Ernst Heinz
University of Hamburg
SCHEDULE AND FORMAT:
The meeting will begin with a plenary lecture on Wednesday evening, June 6
and will conclude with a banquet on Saturday evening, June 9, with
departure after breakfast the following morning. This symposium will be
modeled after the Gordon Conference format. Morning sessions will include
short (15-20 minutes) oral presentations. Evenings will include a plenary
lecture, poster discussions and a social. Posters will be available for
viewing throughout the meeting. Afternoons will be free for discussions
and/or recreation.
REGISTRATION COSTS:
$605 double occupancy; $715 for single occupancy. This will INCLUDE
lodging and meals from evening of June 6 until breakfast on June 10.
FACILITIES:
Sierra Camp is located on 20 acres of lakefront property on the edge of
Desolation Wilderness and is owned and operated by the Stanford Alumni
Association. Sierra Camp has a main lodge and cabin clusters spread
throughout the location. Recreational facilities include tennis, sailing,
canoeing and rowing. Transportation will be available from the South Lake
Tahoe Airport and the Reno International Airport on conference arrival and
departure days.
QUESTIONS?
Kim Traylor of Miami University will serve as the conference
coordinator. Please direct questions on the meeting to her at:
traylokk@...
or FAX 513-529-5715
APPLICATION FORM: for 2001 Symposium on Biochemistry and Molecular Biology
of Plant Fatty Acids and Glycerolipids
Applications can be made by WWW, by e-mail or by FAX.
Because of limited space at the conference center, the number of
participants will be limited to approximately 130. To apply to attend
this conference, please return the application information below by
February 20, 2001. Decisions on attendees will be made by March 15,
2001. Final deadline for abstracts and for registration for the
symposium will be April 16, 2001.
-------------- End Forwarded Message --------------
[Non-text portions of this message have been removed]
To store lipids dissolved in any solvent you must use only Teflon
covered septa, of course Teflon facing the solvent and the silicone
rubber on the upper side. It is convenient to use screw caps with an
hole to verify systematically the orientation of the liner when you warm
or store your vials. All other materials are known to free some
chemicals which give later on spurious spots and peaks on chromatograms.
We use several times the same septa (after washing some minutes in a
sonicator filled with detergent and after rinsing with pure water) until
the Teflon liner is finally separated from the silicone part. All
derivatization processes must also be done in tubes or vials closed with
such device.
Dr C. Leray
Jodie a écrit :
> Hi everyone,
>
> I have a septa / liner / insert query.
> What does everyone use in their sample vials ?
>
> We have had a fairly random selection in our lab
> (plastic, teflon/rubber, and some mystery ones)
> and I think I might treat myself to some new
> ones as those that I've been using don't seem to
> survive a silylation reaction and I'm getting
> 'muck' in my vial, which is showing up on my
> GC.
>
> Any recommendations or "avoid these ones" ?
>
> Is Teflon the liner of choice ? Does it depend
> on which reaction you might be performing, i.e.
> would you use a different liner for storing lipids
> in solvent from that used for enzymatic or
> derivatisation reactions ?
>
> Thanks
> Jo
>
> To unsubscribe from this group, send an email to:
> lipids-unsubscribe@...
> Any problems, please contact Jo at:
> mailto:spbcjsb@...
Hi everyone,
I have a septa / liner / insert query.
What does everyone use in their sample vials ?
We have had a fairly random selection in our lab
(plastic, teflon/rubber, and some mystery ones)
and I think I might treat myself to some new
ones as those that I've been using don't seem to
survive a silylation reaction and I'm getting
'muck' in my vial, which is showing up on my
GC.
Any recommendations or "avoid these ones" ?
Is Teflon the liner of choice ? Does it depend
on which reaction you might be performing, i.e.
would you use a different liner for storing lipids
in solvent from that used for enzymatic or
derivatisation reactions ?
Thanks
Jo
Hello everyone,
In case anyone is interested in this post about GC of
FAMEs and hasn't seen it, I'm copying it to the group.
___________________________________
From the St. Louis Chromatography Discussion Group
(http://www.stlcdg.org/wwwboard/messages/2222.html)
Hans Mueller writes about 'Transesterification with TMSH' :-
Having posted the following message in another forum about a week
ago, without response, there should be an increased chance to find
someone with answers by reposting it here:
Some years ago (J. Chromatogr., 228, 75 (1982)) we tried some highly
touted reagents for methylating fatty acids in the GC injector. It
turned out that we obtained transesterification of inadvertently co-
extracted lipids, as well as ghosting via transesterification of such
lipids which had deposited in the injector. Since then we have
judicially avoided such reagents.
Recently, trimethylsulfonium hydroxide (TMSH) has strongly been
recommended for transesterification of lipids in the injector. I am
still skeptical.
Therefore, it would be highly appreciated to get some information
from someone who criticaly looked at the scope of this reacion.
Some questions: Do lipid deposits, which will form if the reaction
does not proceed 100%, react with subsequent injecions of TMSH (only
clearly visible if no lipids are coinjected)?
Does cholesterol of cholesteryl esters react with TMSH and then
interferes in the FAME chromatogram? Ditto for glycerol of
triglycerides, etc...?
Is methylene formed which reacts with double bonds?
On what criteria is quantitative repeatability based?
About how many injections are possible before the column deteriorates
(I can not believe that some reagent does not enter the column)?
PS: in the meanwhile I found one example of an article
about a problem through interference by hydroxy fatty acids: Vosmann,
et al, Lipids, March 31:3, 349 (1996) + a hint of a caution on the
web site, http://www.lipid.co.uk/infores/lit_surv/ext_meth.html
(There is also a reply to this post from Ralph Calvert on the same
page)
___________________________________
Best wishes
Jo
P.S. We now have 23 members of 'lipids'.
P.P.S. If there are any interesting lipid websites you feel
should be linked to the eGroups website, and aren't, let me
know and I'll add them (or if you register with egroups you
can do this yourself).
http://www.egroups.com/group/lipids
(click on 'links' in the menu to view listed websites)
Hi everyone,
Some of you may be interested in an article in this
week's New Scientist [25 Nov 2000 No 2266 p29-33]
which is actually about the 'aquatic ape' theory,
and how we might be more aquatic than previously
thought. Much of the article considers the controversy
about the theory.
There are some interesting 'fat' issues which I
thought I'd mention :
p30 human subcutaneous fat is 'bonded to the skin'
just as it is in dolphins, seals and hippos. It's
also white fat which apparently is better for buoyancy
than insulation.
p32 large brains - requirement of Docosahexaenoic (DHA)
for membranes of neurons and photoreceptor cells and
Arachidonic Acid (AA) for walls of blood vessels. Both
fatty acids in reasonably short supply and slow to form
within body. Only place where DHA is abundant is in
world's oceans etc. "this is where the first primitive
nerve system evolved".
Jo
This message was sent to all list members registered
to the National Plant Lipid Cooperative, in case any
of you haven't received it and are interested, here
it is:
FIRST ANNOUNCEMENT: 2001 SYMPOSIUM ON BIOCHEMISTRY AND MOLECULAR
BIOLOGY OF PLANT FATTY ACIDS AND GLYCEROLIPIDS
Dear Researchers:
You are invited to attend the 2001 NPLC meeting at Stanford Sierra
Camp near South Lake Tahoe, California.
June 6-10, 2001 (Wednesday to Sunday)
Stanford Sierra Camp at Fallen Leaf Lake
South Lake Tahoe, California.
SCIENTIFIC ORGANIZING COMMITTEE: John Shanklin (Chair), Christoph
Benning, and Basil Nikolau.
SCHEDULE AND FORMAT: The meeting will begin with a plenary lecture
on Wednesday evening, June 6 and will conclude with a banquet on
Saturday evening, June 9. Departure will be Sunday morning after
breakfast. This symposium will be modeled after the Gordon
Conference format. Morning sessions will include short (15-20
minutes) oral presentations. Evenings will include a plenary
lecture, poster discussions and a social. Posters will be available
for viewing throughout the meeting. Afternoons will be free for
discussions and/or recreation.
REGISTRATION COSTS: Final registration costs are not yet available.
However, costs should be similar to the 1999 meeting which were $550
double occupancy; $670 for single occupancy. This will INCLUDE
lodging and meals from evening of June 6 until breakfast on June 10.
FACILITIES: Sierra Camp is located on 20 acres of lakefront property
on the edge of Desolation Wilderness and is owned and operated by the
Stanford Alumni Association. Sierra Camp has a main lodge and cabin
clusters spread throughout the location. Recreational facilities
include tennis, sailing, canoeing and rowing. Transportation will be
available from the South Lake Tahoe Airport and the Reno
International Airport on conference arrival and departure days. More
information is available at:
http://www.stanfordalumni.org/jg/travel_vacation/sierra/sierracamp_con
ference.html
APPLICATIONS: Because of limited space at the conference center, the
number of participants will be limited to approximately 120. An
application form and further details will be provided in January.
Applications will be due by February 15, 2001 and decisions on
attendees will be made by March 15, 2001. Final deadline for
abstracts and for registration for the symposium will be April 16,
2001. A limited number of $500 travel grants will also be available
for students, postdocs and young researchers from the U.S.
QUESTIONS? Kim Traylor of Miami University will serve as the
conference coordinator. Please direct questions on the meeting to
her at: traylokk@... or FAX 513-529-5715.
Sincerely,
Jan Jaworski, and John Ohlrogge
Meeting Organizers
Hi
I'm forwarding this message to the group - please send
any replies to : jcaraveo@... as I've not yet
subscribed Javier, thanks
Jo
>Date: Tue, 31 Oct 2000 15:25:53 -0700
>From: Javier <jcaraveo@...>
>Subject:
>X-Sender: jcaraveo@...
>To: lipids-owner@...
>X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.5 (32)
>X-eGroups-Return: jcaraveo@...
>X-eGroups-Moderators: lipids
>
>Hello!.
>
>My name is Javier, I work in North-Western Biology Research Center in La
>Paz, Baja California Sur, México. I started my doctoral studies in January
>this year.
>
>My main interest in my PhD is the application of the postulate proposed in
>my Master's thesis to understanding in some marine mammals movements
>and interactions with some invertebrates (like a surce of Esential fatty
>acids).
>
>I would like to determine the essential fatty acids in some samples of
>blubber biopsy. This are very small.
>
>For that reason, I would like obtain a reprint of the article:
>
>Prostaglandins Leukot Essent Fatty Acids 1998 Dec;59(6):363-9
>Fatty acid composition of phospholipids and neutral lipids from human
>diabetic small arteries and veins by a new TLC method.Lecomte M, Claire M,
>Deneuville M, Wiernsperger N.
>
>and use your metodology to obtain the profiles of EFA of some replicates
>from each biopsy.
>
>An other hands, some body know an other metodology to obtain the profile of
>Essential fatty acids in very small samples of blobber?????????
>
>
>Thanks for advanced:
>
>M. en C. Javier Caraveo
>
>*******************************************************
>M. en C. Javier Caraveo Patiño
>Investigador (Taxonomia y Ecologia de anfípodos), del
>Centro de Investigaciones Biologicas del Noroeste, S.C.
>SEP - CONACYT
>Tel: (112) 536-33 ext. 3702.
>fax (112) 536-25.
>Mexico, BCS
>e-mail: jcaraveo@...
>********************************************************
>
>
>
http://asci.uvm.edu/nusc43/LIPIDS1.htm
This link takes you to a detailed page with questions
which are marked immediately with feedback, and there
are some good diagrams as well.
I got 51 out of 55 : )
Jo
Dear fellows,
We have received a request for concentrated phospholipids (of marine origin)
from a Norwegian fish feed supplier. Does anyone know if there has been done any
work in this field? Processes estd.? Both on industrial and smaller scale.
Thank you.
Regards,
Sven Haagensen, Ph.D.
Hydro Oleochemicals, Sandefjord, Norway
(The world's biggest supplier of fatty acids based on fish oils)
Thank you very much for this Trevor, that's a great help. I
was beginning to think I was going slightly mad, but your points
on DAG unstability and pyrolysis does rather explain why
everything seemed to turn into a fatty acid !!
I had always assumed the ester link between the acyl and glycerol
was quite tough, but I shall try and treat them more gently in
future.
Thanks
Jo
Without derivatisation you will get substantial pyrolysis in the injector
port since underivatised diglycerides are only poorly volatile and very
unstable at the high injection temperature. Silylation will make the
compound less polar, much more volatile and more stable. It also has the
added benefit of locking the structure so there is no rearrangement of acyl
chains. tBDMS derivatives are more stable than TMS derivatives particularly
if you need to perform some TLC clean-up prior to GC.
Your injector and detector temperatures should be about 20C higher than your
maximum column temperature - this ensures complete loading and prevents
sample condensation in the detector.
Hope this is useful.
----- Original Message -----
From: Jodie <spbcjsb@...>
To: <lipids@...>
Sent: Wednesday, August 16, 2000 4:35 PM
Subject: [lipids] diacylglycerols - do they elute from Non-polar GC columns
?
> I have been testing a batch of Sigma standard
> diacylglycerols on a non-polar GC column as
> follows :
>
> Column : CP Sil 5 CB [50m x 0.25mm]
> Sample : Sigma 178-9 (dipalmitin, distearin
> and diolein [33.33 percent each])
> Program: Start at 160 ^C - 320 ^C at 5^ /min
> Injector & Detector [FID] both at 280 ^C
> (The three compounds are underivatized).
>
> This column gave 3 peaks as I hoped, and with
> correct ratios. I assumed the fact that I was
> able to resolve distearin and diolein was due
> to the length (50m) of the column.
>
> However, when I tried Sigma P3544 (1-Palmitoyl,
> 3-stearoyl-rac-glycerol), I discovered TWO peaks,
> one which coincided with 'dipalmitin' and one
> which coincided with 'distearin'.
>
> Running the four diacylglycerol species together
> gave me only three peaks, however the peak sizes
> seemed to be reasonably similar. It *is* possible
> that P3544 was incompletely resolved from either
> dipalmitin or distearin, but this seems unlikely.
>
> I considered the possibility that my diacylglycerols
> are breaking down (in the injector or column) and
> generating free fatty acids and glycerol, and it is
> these which I am detecting. From this I would have
> expected that the palmitic and stearic peaks would
> be larger than oleic - but the similar peak sizes
> didn't confirm this one way or the other.
>
> Stearic acid (alone) also has a peak corresponding
> with 'distearin', so it would seem that what I am
> detecting is fatty acids rather than diacylglycerols.
>
> TLC plates have confirmed that they start off as
> diacylglycerols at least, so my questions are :
>
> a) Can underivatized (i.e. unsilylated) diacylglycerols
> elute from a non-polar column ?
>
> b) Would a lower injector temperature prevent them
> from degrading, or would this just mean that they'd
> never get on the column ?
>
> c) If they are breaking down to form fatty acids,
> how (if at all) does silylating them help against
> this ?
>
> I understand that silylating them blocks the
> hydroxyl group and makes them more non-polar
> [and thus ideal candidates for resolution on our
> CP Sil 88 FAMEs column], but if they fragment
> before they get onto the column, it's not much
> use... ?
>
> Previously, I have managed to silylate the three
> compounds, and they eluted a little later on the
> non-polar column (i.e. retained for longer) - but
> it now occurs to me that possibly the DAGs were
> eluting as fatty acids and that the silylated-DAGs
> were converted to silyl-Fatty acids in the injector.
>
> Any thoughts ?
> Thanks
> Jo Brodie
> (lipids moderator)
>
>
>
>
> To unsubscribe from this group, send an email to:
> lipids-unsubscribe@...
> Any problems, please contact Jo at:
> mailto:spbcjsb@...
>
>
I have been testing a batch of Sigma standard
diacylglycerols on a non-polar GC column as
follows :
Column : CP Sil 5 CB [50m x 0.25mm]
Sample : Sigma 178-9 (dipalmitin, distearin
and diolein [33.33 percent each])
Program: Start at 160 ^C - 320 ^C at 5^ /min
Injector & Detector [FID] both at 280 ^C
(The three compounds are underivatized).
This column gave 3 peaks as I hoped, and with
correct ratios. I assumed the fact that I was
able to resolve distearin and diolein was due
to the length (50m) of the column.
However, when I tried Sigma P3544 (1-Palmitoyl,
3-stearoyl-rac-glycerol), I discovered TWO peaks,
one which coincided with 'dipalmitin' and one
which coincided with 'distearin'.
Running the four diacylglycerol species together
gave me only three peaks, however the peak sizes
seemed to be reasonably similar. It *is* possible
that P3544 was incompletely resolved from either
dipalmitin or distearin, but this seems unlikely.
I considered the possibility that my diacylglycerols
are breaking down (in the injector or column) and
generating free fatty acids and glycerol, and it is
these which I am detecting. From this I would have
expected that the palmitic and stearic peaks would
be larger than oleic - but the similar peak sizes
didn't confirm this one way or the other.
Stearic acid (alone) also has a peak corresponding
with 'distearin', so it would seem that what I am
detecting is fatty acids rather than diacylglycerols.
TLC plates have confirmed that they start off as
diacylglycerols at least, so my questions are :
a) Can underivatized (i.e. unsilylated) diacylglycerols
elute from a non-polar column ?
b) Would a lower injector temperature prevent them
from degrading, or would this just mean that they'd
never get on the column ?
c) If they are breaking down to form fatty acids,
how (if at all) does silylating them help against
this ?
I understand that silylating them blocks the
hydroxyl group and makes them more non-polar
[and thus ideal candidates for resolution on our
CP Sil 88 FAMEs column], but if they fragment
before they get onto the column, it's not much
use... ?
Previously, I have managed to silylate the three
compounds, and they eluted a little later on the
non-polar column (i.e. retained for longer) - but
it now occurs to me that possibly the DAGs were
eluting as fatty acids and that the silylated-DAGs
were converted to silyl-Fatty acids in the injector.
Any thoughts ?
Thanks
Jo Brodie
(lipids moderator)
The Lipids Group of the Biochemical Society have the
following meetings coming up :
September 5th 2000 (Bath, England)
Cell Signalling to Medicinal Chemistry; Protein and Lipid
Kinases in Disease and Therapy
http://www.biochemsoc.org.uk/meetings/medlect/colworth.htm
19-25 December 2000 University of Sussex (England)
http://www.biochemsoc.org.uk/meetings/programme.cfm?meetno=672
___________________________________________________________
and the Society of Chemical Industry (SCI ) Oils and Fats Group
have the following meetings :
http://sci.mond.org/Conference/Special/OIL.html
September 19th 2000 (London, England)
Palm Oil Supply Chain
November 15th 2000 (London, England)
The future of interesterification in oil processing
April 25-26 2000 (Hull, England)
Oils & Fats across the millennia - 50th anniversary
meeting of SCI Oils and Fats group.
_____________________________________________
February 5-10, 2000
CELL ACTIVATION AND SIGNAL TRANSDUCTION:
LIPID SECOND MESSENGERS IV, Taos Civic Center, New Mexico
For information, contact: Keystone Symposia, 221 Summit Place #272,
Drawer 1630, Silverthorne, CO 80498;
Telephone: 800-253-0685 or 970-262-1230; Fax: 970-262-1525;
E-mail: keystone@...;
Web site: http://www.symposia.com.http://www.proteinscience.org/ProSciDocs/UpcomingMeetings/
____________________________________________
Jo
There is a one-day seminar on 'New Concepts in Lipid
Research', held in central London on July 11th this year.
If anyone wants further details, please contact me.
Best wishes
Jo, moderator
http://www.egroups.com/group/lipids
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