Help on MS equipment selection
Carlos Leomar Zani
We are in a process of purchasing an MS equipment for our institute. We got
a grant around USD 140.000 and received proposals from Finnigan and LECO.
The expected applications are mainly:
-natural product identification
-drug and metabolites quantitation in biological matrix
-structural elucidation of smal peptides, oligosacharides and glycosyl
phophatidil inositols (GPIs) anchors from parasites
Finnigan offered the LCQ-Advantage, a Ion-trap with MS-MS capability and an
electrospray interface
LECO offered the model JAGUAR, an ESI-TOF with mass limit of 6000, high
resolution capability (5-10 ppm) and high speed (100 spectra per second).
Based on these info, I would like to have your help to decide which machine
to buy.
If you choose not loading the list with this subject, please reply to
za...@cpqrr.fiocruz.br
Best regards
Carlos L. Zani
Laboratorio de Quimica de Produtos Naturais
Centro de Pesquisas Rene Rachou-FIOCRUZ
Av. Augusto de Lima, 1715
30190-002, Belo Horizonte, MG, Brasil
tel +55 31 3295 3566 fax +55 31 3295 3115
e-mail: za...@cpqrr.fiocruz.br
Ken Matuszak
established product with stable software, and a very versatile tool. The
MS/MS capabilities, which are a no-brainer on the LCQ will make life
easier for the structural elucication of the bio-compounds.
Sincerely,
Ken Matuszak
Research Investigator
Abbott Labs
jonathan.jones6
LC system and its the easiest thing in the world to use. buy the LCQ.
Jon
Steve Ivkov
mode has the absurd problems with mass ranges. For example, if daughter
ions has m/z = 40, observed parent ions can not be more m/z = 200 and so
on.
Steve
jonathan.jones6
can you elaborate on the LCQ MS/MS problem please? I didn't understand.
Jon.
Steve Ivkov
In my notice I paid attention on an absurd software problem and did not touch
on other.
Xcalibur allows to observe intensity of ions in three mass ranges. The first
is m/z = 15 to m/z = 200 (with the exception m/z = 18 to m/z = 32!!!), the
second mass range is above m/z > 50. As result, Xcalibur does not allow
observe, for example, mass range m/z = 35 to m/z = 205. This absurd restricts
using LCQ in MS/MS mode.
Steve
Mark E. Hail
limitation, but a limitation of the ion trap itself. The ion trap has a low
mass storage limit that is a function of the parent selection m/z. In most
cases this is ~0.3 x the parent m/z. On the DECA, you can lower the RF
level (q) to extend this a bit with the advanced settings. The other thing
to do if you need information at low masses is to perform MS^3, MS^4, MS^n,
until you get the information that you are after. The MS^n capabilities are
excellent for structure elucidation purposes, and in my mind more than make
up for the low mass limit feature. You may have to pay extra for the MS^n
capabilities (beyond n=2) on the LCQ-Advantage. You may want to consider
this if you will be doing a lot of structure elucidation. However, be
prepared to be quickly overwhelmed with data!
Mark Hail
****************************
Novatia Corporation
382 Hidden Oaks Drive
Yardley, PA 19067
tel: (215) 321-3130
fax: (435) 807-3865
email: ha...@enovatia.com
****************************
"Steve Ivkov" <foxs...@ix.netcom.com> wrote in message
news:9dmg7t$lr9$1...@news-int.gatech.edu...
Steve Ivkov
I told that I told. For more clarify look on a few examples.
1. Nitroglicerine (NG), RDX and PETN have in their mass spectra daughter ion m/z
= 46. Parent ion for NG are m/z = 262 and 264; parent ions for RDX are 257 and
259; parent ions for PETN are 351 and 353. What is the first mass spectrometrist
idea for identification these substances? There is MS/MS testing the appropriate
pairs parent - daughter. But it is impossible with LCQ Deca - software designer
restricted the upper board of m/z (=200) for the first mass range and the lower
board of m/z (=50) for the second mass range.
No problems are in using this idea with triple quad. Ion Trap MS/MS and MS/MS^n
analysis is art. The Ion Trap Discovery software and INCOS allow to work with
the similar pairs and what was reason for narrowing of the Ion Trap capabilities
in the Xcalibur software?
2. The range m/z = 18 to m/z = 32 is torn off in Xcalibur. May be mass
spectrometrist can better decide what mass range is correct for his task, huh?
3. Of course, MS/MS^n is a brilliant in the Ion Trap capabilities, but mak into
account that for each higher n, the system allows narrower mass range...
PS. Jon did not say how many samples he are going to analyze. LCQ has the heater
- capillary on the enter and cleaning of this capillary by overheating,
mechanical and chemical procedure not warranted the perfect results.
Steve
dieter.z...@bayer-ag.de
++++++++++++++++++++++++++++++++++
Dear Carlos, for drug metabolism and quantitation studies in biological matrix
the LCQ is clearly the right choice, given your budget (with higher budget,
there would be some other opportunities). The restriction that Steve Ivkov
mentioned (if product ion mass is below m/z 50 the parent ion mass is restricted
to not more than m/z 200) will seldom happen, since mostly you will find the
product ions at > m/z 50 much more characteristic for your metabolites than the
very small fragments. Therefore don't worry about this (theoretical) restriction
and have fun with the LCQ!
best regards
Dieter Zimmer
______________
Dr. Dieter Zimmer
Bayer AG
Preclinical Pharmacokinetics
PF 101709, Building 468
42096 Wuppertal
Germany
Phone: +49-202-36 4173
Fax: +49-202-36 4224
e-mail:Dieter.Z...@Bayer-Ag.de
Steve Ivkov
1. Xcalibur designer's restriction on mass ranges is not theoretical
restriction and causes many unnecessary troubles.
2. I gave three examples with MS/MS parent – daughter pairs from my
practice. It is not theoretical examples.
3. For structural elucidation of small molecules, device should work with
small fragments in MS/MS^n mode.
Carlos is in a process of purchasing MS equipment for the institute and
asking information about benefits and weak spots of two kinds of devices.
Now he is going to use one device for investigation of multi-component
samples in biological matrix. It is well known that LCQ is good device and
the marketing department of FINNIGAN is presented any information about
LCQ benefits much better than user's dithyrambs. How about weak spots?
Could you?
Steve Ivkov, Ph.D.
Michael Sherrell
We could provide you with an LCQ Classic with ESI and APCI sources for
US$89,500 crated for overseas shipment FOB Chicago. We would have it
certified by Finnigan before being crated; you would have Finnigan's
blessing to use your local Finnigan service engineer for installation and
maintenance.
Michael Sherrell
Grizzly Analytical
707 887 2919/fax 707 887 9834
www.grizzlyanalytical.com
mi...@grizzlyanalytical.com
"Carlos Leomar Zani" <za...@netra.cpqrr.fiocruz.br> wrote in message
news:9dgsgp$25q$1...@news-int.gatech.edu...