Comments on merits of Mass Spectrometers
We have used all three manufacturers of mass spectrometers and we currently
have one VG 602, one Finnigan-251, and two Europa instruments (1 GEO-Hydra
and 1 20-20). In fairness we have only had recent experience with Europa
and Finnigan. Both Finnigan and Europa have provided us with good
technical support.
As for the design of the instruments, the 251 is built like a tank. It can
withstand treatment which would have grounded our VG 602 in a second and
has many very good design features. I assume the 252 has similar
qualities. However, in Miami we have an environment which is very harsh.
There are frequent break downs in air conditioning, humidity control, power
regulation etc. As a consequence we have had a lot of electronic problems.
In our new laboratory we have our own air conditioning system which allows
us to be independent when the university wants to safe money by turning off
the AC at night to save money. As result of the generally good technical
support from Finnigan we have kept our instrument running and have
processed approaching 100,000 samples. I have several complaints about
Finnigan. In particular the cost of their spare parts is outrageous. We
are now on our third bellows assembly, each one cost $5000. We have had to
replace emission control units at $3000 each, boards at $1000 each,
filaments at over $600 each (the price has recently been reduced to $350),
valve tips ($500) etc etc. We also use about $50 of liquid nitrogen a
day. One thing people talk a lot of BS about is the cost of turbo pumps.
Our instrument is 12 years old and we are still on the original turbo pump.
We do not have the unit water cooled. In spite of the poor air
conditioning it keeps on running like the energizer bunny. We have
replaced two oil diffusion pump heaters, two ion gauge heads, and two ion
pumps in the same time period. The instrument is good and is still going
strong with a lot of TLC. The software is very Finnigan. We upgraded to
ISODAT which was not designed for our system. After some problems we were
able to get Finnigan to change some things, but they then washed their
hands of the system. Isodat still does not work properly. I was told
that I would have to pay them to get the problem fixed. We have never
received any information from Finnigan about software updates. Of course
the software works sort of, but we cannot have the computer on the network
and share the data easily with the rest of our system. This is essentially
the same software Finnigan is providing now. In contrast Europa provides
almost 24 hour service on software problems and provides free updates for
life. The software is Windows based and therefore you can use a network to
move data around and theoretically (we have not tried this yet) use a modem
to check on your instrument from home.
I recently purchased two Europa instruments. Price was a consideration.
The 20-20 is attached to a CN device, while the Geo is attached to water
processing unit and a GC. We essentially have now a lab with dedicated
instruments. The 251 is attached to a common acid bath system which can
run samples as small as 10 to 20 ug. One reasons why I purchased the
Europa was that the salesperson was the same one who designed the
instrument. I did not get the feeling that as soon as I signed the deal
that I would never see the salesperson again. At least until I had some
more money. That person also came and installed the instrument.
In terms of sensitivity the 251 and the GEO-hydra are comparable. In
terms of the hydrogen the Geo-hydra is significantly better than our 251.
We were able to get the ‘correct' answer for the Ring test samples one day
after the instrument was installed. Carbon and oxygen are about the same
as our 12 year old 251. The dual inlet on the GEO is a significant
improvement on the 251. The bellows on the 251 are terrible and the design
of the inlet is poor.
Our Europa 20-20 is attached to the Europa equivalent of a CN analyzer as
well as a Gilson autosampler which can analyze DICs and waters via
continuous flow. Europa have also adapted one of these Gilsons for CO2 and
H2 equilibration. The device has no name but it is in principal similar to
the multi prep offered by VG and the existing gas device offered by Europa.
We are calling it the WET device. This unit runs 59 samples at one time
and will be able to jump from CO2 to H2 and equilibrate CO2 while running
H2. At the moment the device is giving us 0.07 per mille on oxygen and
1.8 per mille on hydrogen. We expect this to improve once problems of
temperature regulation are improved.
In closing I would say that you cannot expect mass spectrometers to perform
like Hondas. Maybe if the Japanese starting making them they would.
However, they do not. These instruments need people to look after them who
understand the problems. If you know the right questions and the right
people to ask you can usually get by with minimal problems. This applies
to Europa, Finnigan, and VG. As regards the comments about not purchasing
peripherals but building your own I have the following comments. It is
always gratifying to build an extraction line, but one can now a days
obtain significantly better data from automated systems. It is in my
opinion it is a significant cost saving to purchase a system such as an
automated organic carbon and nitrogen combustion system rather than trying
to build your own. I would always recommend buying automated systems for
carbonates, organic carbon and waters. If you want to try some more
experimental methods then conventional vacuum system might be more
appropriate.
In summary I think that one should consider serious all three
manufacturers. The Eupora instruments we have are truly fantastic. Of
course we have had some teething problems, but that is normal. Our
Finnigan-251 is also a great machine, just a little long in the tooth. I
certainly will be happy if the Europa instruments perform as well in the
long term as the 251.
The key is to keep an open mind and get the best deal for you. If you
have the money then I would probably buy several 252s. However, if you
want to do more than one isotope and have more than one peripheral I would
buy several cheaper instruments and forgo the machismo of the 252.
Here are some pros and cons.
Pros: Finnigan
1) Design: Ion source design is superior in the 251 to anything else
available. High voltage provides better sensitivity
2) Robust
3) Good parts availability, good tech support, good parties
4) Great booth at GSA
5) If instrument completely breaks down, can be used as an artificial reef
6) Young infants can be sent to sleep by the hissing of leaking solenoid
valves
7) 10 Kv is ideal for starting aging pace makers
Cons:
1) Price of the instrument and spares
2) Design of cold fingers uses too much liquid nitrogen
3) Software is out of date. Manufacturer does not update software or
inform users of software updates. New software will not support old
instruments.
4) Cold fingers suck
5) At the factory they make you eat in the cafeteria.
6) Bremen is not much better than Crewe
Europa
Pros
1) Price of spares are less than Finnigans by between 2 and 3 times.
2) Software is good, but..
3) Cold fingers use less LN
4) Dual Inlet system is nice.
5) Compact design
6) Will be able to do hydrogen in continuous flow mode
7) Get to go out and drink beer with engineers
8) No cafeteria so they take you out for to the pub for lunch
9) The factory is near Provac so you can get your 251 bellows rebuilt
while your having lunch
Cons
1) Software has bugs
2) Communication with instrument uses a serial link which slows down
computer response.
3) No parties
4) Booth at GSA sucks
5) Crewe is mighty fine in winter
6) Edwards 1.5 pumps leak more oil than a British motorcycle
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Peter K. Swart
Professor and Chairman MGG
RSMAS
4600 Rickenbacker Causeway,
Miami FL 33149
305 361 4103 (office)
305 361 4912 (lab)
305 361 4632
Home Page
http://mgg.rsmas.miami.edu/mgg.htg/pswart.htm
Stable Isotope Laboratory
http://mgg.rsmas.miami.edu/mgg.htg/groups/sil/index.htm
Comparative Sedimentology Laboratory
http://mgg.rsmas.miami.edu/mgg.htg/groups/csl/index.htm
Division Home Page
http://www.rsmas.miami.edu/divs/mgg.html
Sclerosponge Web page
http://mgg.rsmas.miami.edu/mgg.htg/groups/sil/workshop.htm
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