The news on advice on new mass spec purchases is timely. We (at Stanford
University) are now in the final stages of setting up a new stable isotope
facility. The only thing missing at the moment is a mass spec(s). I have
spent the better part of a year talking with many colleagues about past and
present instruments they have had in their labs over the years. The
decision of which instrument to purchase is a difficult one, one that
should take more than a 'little' time. The analogy to purchasing a car is a
fair assessment and the fear of purchasing a lemon is foremost in our
minds. Funds for these instrument are difficult to acquire and some of us
rarely get a second chance. All too often these instruments become the life
blood of our labs and our research hangs on the success of these tools.
With luck we will be making an instrument shortly.

The three main vendors (Finnigan, Micromass, and Europa) make fine mass
specs. The MAT 252, Optima, and 20-20 essentially have the same sensitivity
and linearity. To me the difficult choice is choosing the peripheral to
attach to the instrument. Here is where there is large debate. Kiel vs
multiprep vs CAPS, continuous flow systems, water devices, etc. They all
have their pros and cons or controversies if you wish. I have talked on the
phone with a number of you on this list over the past year and thank you
for all of your input. I have also read on this site about some incredible
sample sizes from some of the devices out there, numbers the factory would
never quote or admit they could reach with these peripherals. Only recently
are the manufactures saying they have broken the 10 microgram barrier with
carbonate systems (i.e., Kiel III and multiprep). For example, take the
isocarb or autocarb device from both Finnigan and Micromass. There are lots
of these systems out there attached to Delta's, SIRA's, Optima's, Prism's,
and the like. What I have found out from my reading and discussions with
many of our colleagues out there, is a technique that works in one lab
doesn't necessarily mean it will work in another (even given the same
instrumentation). Different amounts of acid, varying acid surface area,
sample boat design, sample spillage prevention, different run times, pump
time, special source tuning, the list is endless. On the negative side,
this information is confusing and can complicate the decision making
process for a lot of colleagues out there. I know it made me dig deeper to
acquire more details about the these various peripherals. But, on the
positive side it demonstrates that given time you can find what works best
in your lab and push these instruments and peripherals to the limit. Don't
get me wrong, I am not suggesting that there is misrepresentation going on,
I am just pointing out that all instruments and peripherals are not created
equal.

Over the years I have been able to keep a SIRA24 online and old VG602's at
spec with lots of TLC. Something all mass specs require either from the get
go or as they age. In the labs I have worked, I have gone to length to
minimize the effort required to obtain samples off-line. I am looking
forward to the pros and cons of adding automated analyses to the new lab.
We must keep in mind that these instruments are not plug and play. To
expect that, you are going in on a purchase wearing blinders. And yes, I
know some of you have had installations blessed by the mass spec gods and
others cursed.

My experiences over the years have been with Europa and Micromass/VG. I
have had good relations and service from Europa while my dealings with
Micromass have been mixed but favor on the positive. My experience with
Finnigan has only been on the sales end when the lab at South Carolina
purchased the SIRA24 in 1982 and recently. To learn more about Finnigan, I
have to rely on our fellow colleagues out there, and learn from their
experiences. The final choice we make will essentially be made over who
gives us the best package for the dollar. I feel that given time all of the
instruments out there will do the job well. All of the sales reps I have
worked with over the past year have put in a good effort to present to us a
'best' deal.

If anyone is interested in the information I have acquired over the month
wrt the three mass spec vendors, feel free to contact me. Those of you
interested are welcomed to come visit our new facility at Stanford
University once it is online.

Cheers,

David Mucciarone

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David A. Mucciarone
Stanford University
Department of Geological and Environmental Sciences
Stanford, CA 94305
-Temporarily at Rice University-
(713) 527-4880 (O), (713) 285-5214 (F)
Geology: x-2356
e-mail: [log in to unmask]
WWW: http://pangea.stanford.edu/~dam

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