Hi Everyone -
I wanted to thank all those who responded to my post about chemists with
reactive/time sensitive samples still wishing to use our CASE autosampler
system. I received 11 responses and as is always the case with this group,
there were lots of great ideas. A summary is rather difficult so below you
will find my original post followed by all 11responses with names removed. I
have not had time to implement anything new related to this issue yet - if
anyone would like to follow up with me sometime in the future to see what
we've done to address this - I'd be happy to discuss it with you.
Cheers,
Mike
Original Post:
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We have a Bruker AV-500 here where the defualt mode of access is via
ICON-NMR and a CASE sample changer. For those of you unfamiliar with this
equipment, the CASE is not a robot but rather changes samples 1 position at
a time in a serial fashion. The system works extremely well. We have had
some unhappy users lately and these users are chemists dealing with reactive
or otherwise difficult samples. Tubes with J-Young valves are not allowed to
be used in the CASE. What these chemists are doing is placing "dummy
samples" in the queue to hold their position and sometime before it's time
for their sample to drop in the magnet, they revisit the NMR center to
replace the dummy sample with the "real sample". This system has many
sources of problems including a sample in an earlier spot failing to lock or
shim, someone adding more experiments to an earlier sample, etc etc.
Typically these real samples are simply standard NMR tubes and caps wrapped
with a bit of teflon tape. I should emphasize that the spectrometer can also
be accessed via a hands-on booking and this is what I am selling to them but
these chemists would rather use the sample changer given the convenience
factor, although they are being inconvenienced at the same time by having to
constantly monitor the timing of the queue.
I'd love to get some feedback from this group on this issue. For those of
you with sample changers, I'm sure you must have faced similar issues. What
types of solutions, if any, have you implemented to allow researchers with
reactive, time sensitive samples to be able to still use the sample changer?
Responses:
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Have you tried to use the J-Young NMR tubes from New Era Enterprises? New
Era allows you to specify the length of the tube to the valve, so that the
valve is very close to the spinner. As a result, you "should" be able to use
these tubes in the CASE since you are not using a robot arm. I have used
these J-Young NMR tubes from New Era before, as well as spinning them with
no problems. But at J&J we have the BACS, not the CASE, so I can not speak
as a certainty of using them with the CASE.
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We use our BACS 120 sample changer primarily at night and allow walk up
access during the day. As a note this is on a Cryoprobe and we do allow
J-Young tubes only when the system is in the walkup mode and we limit access
to the more advanced students.
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Your wish to Santa should be for a B-ACS 60 or even 120. I agree that the
CASE can be a convenience, but I'm spared the 'problem users' you are
describing. IMHO, a B-ACS setup is the way to go for your time sensitive
samples. In ICON configuration you can delegate chosen users priority
permissions, and by enabling priority samples are run immediately (or when
the current sample is done), I believe your problem could be solved. Only
problem with my suggestion is that I doubt that a CASE can be exchanged for
even a B-ACS-60 without spending more money, but it might just be worth it.
B-ACS's are really convenient, I have it set up without the priority
enabled, but instead I have activated the nighttime feature which allows my
users to set up longer acquisitions (13C's or 2D's) to take advantage of,
otherwise, idle night and weekend (and holiday) time.
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I am really surprised that the chemists don't want to run these kinds of
samples manually. I am also not a fan of the CASE. I had one on loan once
and found it to be awful. We do have several of the original BACS sample
changers and they are extremely robust. But we have spectrometers that also
do not have any sample changer so they have no choice but to become
proficient at manual acquisition if they want to use any of the other ones.
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These are topics of real interest for our facility, since we have similar
concerns here. We got a new Mercury-300 with 100-sample SMS robot about two
years ago; the sample changer/automation replaced automation we had been
performing previously with an AC-300 equipped with a BACS-60 sample changer.
The software was, of course, a big improvement, but we were surprised that
the SMS pincers could not accommodate J-young tubes, or for that matter,
anything that was not a standard 7" or 8" 5mm tube (a standard 9" tube, as
one important example, could not be run).
These limitations were most definitely not ok in our facility, where
in-house made J-young tubes had been used with no problems for >10 yrs with
the BACS-60 (as well as 9" tubes, which are very common). The BACS could
also accommodate a 5mm tube of essentially any length--that would still spin
stably. The typically 10 to 11" in-house made J-young tubes used by a
number of groups were therefore ok with the BACS system. We finally had our
machine shop make us new pincers for our SMS that grab the spinner, rather
than the tube (something very similar is available from Rototec). Any
diameter tube (e.g., 3mm) can now be submitted, as well as J-young tubes.
Careful adjustment/calibration of the SMS robot allows 9" tubes to be run
(with or without the new pincers), so commercially sold J-young tubes can be
used anywhere in the sample tray. Longer tubes can be run in a few of the
spots along the back row of the sample trays. So our primary issues were
resolved with these changes.
I have not seen requests for time-sensitive samples, but likely only because
students here have not gotten a hint that such could be accommodated. I
have been looking into this recently, but not yet in depth. I do know that
ChemPack 4.0 has very good capabilities for setting up and controlling
priority samples that might resolve these issues for Varian users. I have
also seen sophisticated sample loading/scheduling software built into
IconNMR, but only for use (I believe) with the new (or upgraded) BACS
changers.
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I was a bit confused by your posting, but are you saying that many of the
problems arise because the previous sample in the queue runs into
difficulties? One way to overcome the difficulty of a previous sample
sending the lock and shim way off base is to have the owners of the
sensitive samples run two tubes. The first tube, a blank with the same
solvent set up for a proton run with minimal scans, can be used to bring the
lock and shim parameters back to a reasonable state, so that the second
(real) sample runs properly.
We run two instruments with BACS-60 sample changers, and like you find the
system works extremely well, even though they are both old AC instruments
running DISNMR. We have one group which works with light-sensitive samples,
and like your users, they place a dummy sample in the queue to hold their
place. I insist that it be a tube with the same solvent, so that if they
don't get back in time, the automation run is not interfered with.
Also, because these instruments are primarily for routine samples, the users
are limited in the amount of time they can use at one time. The idea is to
give as many people as possible access to the instrument. With DISNMR, they
can't alter their booking without hanging up the automation, although I know
that is possible with the newer software. I have found in the past that a
brief removal of booking privileges works wonders with repeat offenders,
although on a busy instrument the scorn of their fellow workers is often the
best cure of all.
Incidentally, the BACS-60 handles J-Young tubes without any problem. Do they
get hung up in the unit while they are being inserted? When we bought our
AV500, Bruker threw in a 6-PACK sample changer, as it was being
discontinued. I removed it after only two or three weeks of use because so
many tubes hung up while being inserted and removed.
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Does your automation capability include email capability? If so you might
include a check box to have the User X get an email marker from your system
to let him know when he should be coming into the lab. For example if
experiments A, B & C are in queue ahead of him he might get an email from
the instrument at the completion of experiment B informing him that
experiment B is complete and experiment C is currently in process. You may
also consider placing a web cam pointed at your sample changer and posting
the image someplace on your website so they can monitor it from their
office.
We have a robot in our lab so serial acquisition order isn't an issue, but
rush samples has been an issue from time to time. One of our solutions has
been to implement a "Priority Rush" button which zooms a sample all the way
to the front of the queue, BUT first it sends an email to everyone who got
pushed back and their bosses. The user submitting a priority sample is given
an opportunity to explain his need for rushing ahead of his colleagues in
that email I'm a big fan of peer monitoring, in a company setting where you
have people working with people for long periods of time it's an excellent
"throttle control mechanism". This year out of 4000+ automated acquisitions
we had about 40 priority samples.
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Can you offer them a specific time during the day, where the sample changer
comes off? I did air sensitive samples as a grad student. I could target the
sample prep for a specific NMR time, without too much inconvenience. Then
you could restart the CASE afterward. I think this would be the best case
scenario for all involved. It also sounds like they are afraid of or don't
want to try anything new. So the rewards of any solution have to be greater
than the pains that are perceived to be there. You might present different
usage ideas to that group, as well as some of the other users. I find that
when consulted people will come around to new ideas quicker. They also can
help you refine ideas.
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Are the users with reactive samples looking at one sample-at-a-time? If so,
then you can try a hybrid system. Here's what I mean:
1. The user books the time in FACES.
2. You suspend the queue and setup the "off-line" queue.
3. On the spectrometer workstation, you start a new ICON-NMR session where
the user with the reactive sample can set up the experiments he want to run.
The user can then go away and everything happens in the background just like
regular ICON-NMR.
I would recommend turning the monitor off and doing whatever you can to
prevent SOMEONE from adding more samples to the dummy queue.
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People will go to great lengths NOT to learn how to run an NMR spectrum. It
is a sample changer that makes the ignorance possible. You are doing the
right thing to deny users with unusual tubes from using the sample changer.
When I see such tubes, I just cut them and put them in the rack with the
"done" samples. It doesn't take too long for word to spread and people will
eventually respect the rule.
Sample changers are very efficient and have there place however, they work
best with standard tubes and standard caps.
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You've obviously realised the big restriction of the CASE sample changer in
that it doesn't allow priority setting like the BACS does. You might be
already doing this but one quick and easy thing you can implement is to pass
the IconSetup & IconHistory files to a "chemist accessible" location. This
would allow them to at least check on the progress of the sample changer,
see what samples and experiments are in front of them in the queue and, with
a bit of mental arithmetic, allow them to judge better when to take their
sample to the spectrometer.
Other than that, I have a feeling that your only option is a more
intelligent sample changer ie BACS or SampleJet
----------------------------------------------------------------------------
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Michael D. Lumsden, Ph.D.
NMR Facility Coordinator
Room 428, Atlantic Region Magnetic Resonance Centre
Department of Chemistry, Dalhousie University
6274 Coburg Road
Halifax, Nova Scotia, Canada
B3H 4J3
phone: 902-494-1635
FAX: 902-494-1310
http://armrc.chemistry.dal.ca
Received on Fri Feb 16 2007 - 17:46:17 MST