-- -=-=-=-=-=-=-=-=-=-=-=-=-=- / George D.Sukenick, Ph.D. \ \ NMR Analytical Core Facility / / Sloan-Kettering Institute \ \ g-sukenick_at_ski.mskcc.org / / 212-639-5505 \ -=-=-=-=-=-=-=-=-=-=-=-=-=-=- ----------------------------------------------------------------------- Dear Rudi, Are these JY tubes manufactured by Wilmad, and if they are, what was the part no.? This is of great concern to us at Wilmad, if they are our tubes. Please reply! Best regards, Ralph Flachsbart Wilmad Glass Co. ----------------------------------------------------------------------- Hi Rudy: When our Bruker DMX 500 with Boss-2 was installed in 94 (with a probe from 94, too) we had a similar problem of inserts breaking every few weeks. The problem was not spinning (we never spun) or tubes but occurred on sample insertion. I seem to recall that Bruker added or changed an insert on the top of the probe (the round cone-like disk) and after that we had NEVER had another insert break. Although this seemed an improbable fix, it worked. (on the other hand, maybe I'm remembering wrong) Deane Alexander at Bruker, Billerica was our installation engineer and was responsible for its correction. I'm not sure if he is still there. Hope this helps John John Decatur, Ph. D. NMR Facility Manager Department of Chemistry 3000 Broadway, Mailcode 3179 Columbia University New York, NY 10027 212-854-2155 (voice) 212-932-1289 (fax) decatur_at_chem.columbia.edu ----------------------------------------------------------------------- Hello Rudi, Our ARX250 with a 5mm qnp probe has a broken insert every year. During the summer when more students are doing nmr it breaks more frequently. Once the magnet was not perfectly vertical because the air pressure in the three tires somehow lost balance. After that I often use a leveller to check the straightness of the magnet. Sometimes students eject samples without turning off spinning, that could break the insert because the tube motion is not just going upward. When I couldn't understand why the insert breaks, I started to think it must be the tube they are using. A lot of students are using this nmr and some use the cheapest tube to run quick 31P experiments because they don't need to lock and shim. Other two high field spectrometers never have any broken inserts. The only reason I can think of is that they do not have such frequent sample handling. Wei Wei Wycoff Department of Chemistry 601 S. College Ave. University of Missouri-Columbia Columbia, MO 65211 USA voice: (573) 882-3291 fax: (573) 882-2754 email: WycoffW_at_missouri.edu http://chem.chem.missouri.edu/nmr/nmr.html ----------------------------------------------------------------------- Hi Rudi, While my server gets around to forwarding your message, I'll give you my 2-cents. We use J-Young tubes here all the time (three major user-groups), and haven't had a broken insert yet. However, I have been concerned about the issues you raise since these top-heavy tubes became available. The Bruker eject/insert system seems to be the least friendly of all, in terms of being ungraceful in inserting the sample. I have gone through the process of fine-tuning the air-flow via the BSMS keyboard, and I haven't found settings that are good for all samples. I use the heavier, ceramic rotor with the J-Young tubes so that the mass of the rotor offsets the mass at the top of the tube. I also recommend that my users order shorter tubes (as you recommend). You can order them that way, rather than shorten them yourself...and we've had a few glassblowers who haven't understood the importance of the valve being straight and balanced. Short of your "fishing-line" idea, I have my users gently push the sample assembly as low as they can in the upper-stack after they press the button to lower the sample. I find that the sample stays at the top longer than necessary as the eject air is lowered, but it drops earlier in the sequence if it is pushed down about 4 inches as the air-flow drops. There is a very clear, audible difference is the "clunk" when this is done...the clunk is much quieter. If the users just "has" to spin, I recommend the lowest speed possible... 11 or 12 Hz, to minimize wobbling (that's sample wobbling, not "Bruker" wobbling <grin>). This is a big concern, and I haven't had a probe-insert break in 10 years, except for whey someone dropped the probe, which is another thing altogether. Maybe I'm just lucky, or my users are more careful...who knows. I do like the fishing-line idea...hmmmm, now to add a few pulleys, and stepper motors! I hope you get some responses with good ideas. I'd be happy to hear them! Cheers, Rich S. ---- Richard Shoemaker, Ph.D. Phone--(402) 472-6255 Instrumentation Director, Chemistry FAX---- -6964 Research Associate Professor, Chemistry University of Nebraska-Lincoln URL: http://www.chem.unl.edu/nmrlab.html ----------------------------------------------------------------------- Hi Rudy, I look after an aging AC200 here at the University of Arkansas at Little Rock, and have experienced the same problems you describe. The heavier spinners were our main problem; but this was due to an incorrect setting on our inlet (sample lift) valve - all samples were hitting "bottom" with velocities too high for the insert to bear. Once the ceramic spinners were eliminated we had no problems; but now that the lift gas pressure setting has been corrected we can run ANY spinner-tube combination. Check for any obstructions in your air lines and that the regulators are all functioning as they should on your air supply. These could cause momentary drops in pressure, effectively blocking the air, and causing your samples to drop the last few inches or so. Hope this helps! Best of luck. Sincerely, Kirk Babb kbbabb_at_ualr.edu Analytical & Solid State Materials Lab University of Arkansas at Little Rock ----------------------------------------------------------------------- Rudi, The last time I had a slew of broken inserts was with our old WM-250 and WM-500 at Yale. At the beginning of every fall semester we would have a rash of broken inserts. This was caused by two things. First, the old upper stacks didn't have the constriction at the bottom that helped straighten out the spinner as the tube entered the probe. I got three brass inserts from Bruker and put them in all three WM upper barrels. This helped immensely. Secondly, the rate at which the sample drops could also be a problem. The only way this would change is if there was a leak in the sample lift plumbing. The WM consoles just had a valve so the impatient graduate students would just turn it off abruptly. Another broken insert! In all these cases the inserts were broken in the top third of the glass. I think you appraisal is correct that the tubes are hitting the thermocouple and then breaking the bottom of the insert. In my experience the type of spinner and the length of the tube had no bearing on whether the insert was broken or not. The other possibility is the depth gauge being set so the tube goes in too far. I eliminated this variable by having the shop machine a gauge of lexan with a fixed depth and a mark for the center of the coil. I hope this helps! Regards, Peter ----------------------------------------------------------------------- Hi, Rudi Your experience is very similar to one we had in our facility before we switched to higher grade, more expensive NMR tubes and a fixed sample gauge. On our dpx300 spectrometers running automation with autosampler all the time, we had to replace insert at least once a month on average before the swicth. Now, it rarely happen. The probes on our 300MHz spectrometers are farely old, so we are allowed to change inserts ourselves. On our lately installed 400MHz and 500MHz spectrometers, we have not experience any insert breakage yet with the higher grade NMR tubes. Since we are not allow to open newer probes, we are using more expensive NMR tubes because we do not want to see a broken insert once a month. I am sorry that we do not have any direct experience on J. Young NMR tubes. - Xiaohong Liu Discovery Analytical Sciences (Dept. 115) 5 Research Parkway Wallingford, CT 06492 Phone: 203-677-7535 (phone) fax: 203-677-7702 (fax) email: liux_at_bms.com office: 455A ----------------------------------------------------------------------- I have used the new BBO probes in a 500 and have had no such problems. I suspect that you have an allignment problem. The bore of the magnet is very much wider then the BOSS II and usually this is fixed with insulating tape wrapped round the base of the BOSSI. However if the same fix is not applied to the upper barrel and there is a small problem with the mating faces then the barrel will be forced out of line causing the probe base to hit the insert as the tube descends. The isert may be strong enough to withstand a normal tube but the J. Younge tubes are that much heavier........ Let me know. Good luck Marc ----------------------------------------------------------------------- Dear Rudi, It might be, among other possibilities, that the probe itself( I mean = due to imprecise manufacturing) may be the culprit. I guess you use = usual BB probe without gradients. There should be 5 mm inner glass, = around 10 mm glass tube and thick outer glass or dewar. The ceramic top = should lie on that outer glass(dewar) mainly, not on the inner glasses. = It seems that the ceramic top height lies on the inner 5 mm insert = instead of in your case. Sooner or later the inner insert will be = broken, most often during temperature experiments. I've seen this defect = on the early design probes (somewhere in 80's). If it is your case the easiest you can do is either to shorten the 5 mm = insert a bit with a proper diamond instrument either to put a proper = thin ring between ceramic top and outer thick glass. Keep in mind the = temperature effects of the materials! Best regards, Sergey=20 Sergey Meshkov, Service engineer, BRUKER Ltd., 117913 Moscow, Leninskij Prospekt, 47 Institute of Organic Chemistry, Tel. / Fax: +(7 095)137-6751 ----------------------------------------------------------------------- Dear Rudi, I think it can be both misfortune and/or construction. We here have an aging AC-200, 5 mm broadband probe, and we have broken (at now) the glass inside the probe only once in 9 years. I suspect the free access of students to the instrument to be a danger for the probe, especially with variable temperature operations (from - 90 deg to + 130) . Anyway these are our results. What I want to point out is that other collegues of other universities, operating the same machines, break regularly the glass every few weeks : I suspect the inadequate mounting of the probe parts (misalignements etc) to be the culprit, but it's a hard thesis to support with the Bruker maintenace team ! If the tube slide down in the ceramic spinner, you should see it after ejecting the sample, checking it back in the gauge. I suspected this kind of behaviour, but a careful check has not shown this phenomenon. Moreover, at least in our instrument, when the samples are iserted, the (heavy) ceramic spinner produces a distinct "clack" sound, but it beats on the aluminum alloy of the "bearing" site in the shim assembly, not on the glass (or ceramic) parts of the probe parts of the probe (I regularly every few weeks dismount the assembly to clear the dirty from the bearing holes making samples not to spin ...ah, the students .. the came to the instrument wearing the dirty lab gloves ...). Again, if can be some misalignement in the whole shim assembly/probe/insert (of the matter of tenths of millimeters) something can happen, in my opinion... A question : after replacing the glass we had to completely retune the probe, especially 1H observe/decouple, and make adjustements to PW90 values in heteronucleuses. Is this in your experience too ? Good look ! Stefano Antoniutti =================================================================== Dr. Stefano Antoniutti Voice : +39 041 / 2578555 Dipartimento di Chimica Fax : +39 041 / 2578517 Universita' Ca'Foscari di Venezia Dorsoduro 2137 I-30123 VENEZIA e-mail: anto_at_unive.it =================================================================== ----------------------------------------------------------------------- Rudi, We have an inverse probe from about that era that was an insert eater too. Brian Andrew suggested replacing the white teflon cap that sits on top of the insert. The new style has a tapered hole thats larger at the top, the old one was a straight hole that was harder for the tube to hit. Since the change, we haven't broken an insert. hth, dave scott iowa state university ----------------------------------------------------------------------- This was such a counterintuitive-but-effective trick that I am compelled to post it. (Tell me if I'm wasting bandwidth) The gentlest way to lower a tube into our GE-Nicolet (GN-500) spectrometer was to drop it down the stack with the eject air off, then immediately cup your hand over the top of the stack, sealing it. The tolerance between the spinner and the stack was so close that the sample glided down slower than Alice in the rabbit-hole. I discovered this myself in a moment of panic; it was also mentioned by Jerry Dallas, who did the training for GE. (Test this in your spectrometer with a taped-over spinner, not a glass sample!) I later did a lot of work using ceramic spinners in a Bruker AM-500. We didn't always have enough air pressure to get them out. One solution was connecting a hose barb at the top of the stack to an aspirator; with the stack cover on. The vacuum got the sample moving; the available air pressure was enough to float it the rest of the way out. In the end, though, we settled on the "fishline" method. The final refinement was to use a copper wire hook which we could remove after lowering the sample, so we could spin. For removing the tubes there was an art to making the end of the hook like a slightly-unwound spring, so by turning the wire you could guide the NMR tube cap into its wire cradle. Probably the right way to address Rudi's problem would be: Adjust the insert air (does Bruker have a "slow-drop" valve?). How do the Bruker spinners grip the tube? Can you insert new O-rings that are either slightly tighter or stickier? -- Roger =========================================================== Roger Kautz, Staff Scientist, Ph.D. Barnett Institute of Chemical and Biological Analysis Room 341 Mugar Life Sciences Bldg. Northeastern University, 360 Huntington Ave. Boston, MA 02115 tel (617) 373 -8211 fax(617) 373-2804 email rkautz_at_lynx.neu.edu ----------------------------------------------------------------------- Hi Roger, I don't think it's counter-productive at all!! We've used this trick on the GE-Omega systems for years!! I think every field engineer from GE used it because of the painfully slow eject/insert cycle in the software. It is hard to use the "hand-induced-vacuum" trick with the Bruker upper-stack because the upper ring isn't flat (can't get a good palm-seal). I have used the same trick on our older manual-insert Varian instruments also...works great. To eject heavier samples (ceramic-spinners, J-Young (or other top-heavy) tubes, or over-filled 10mm tubes), we have good luck with simply increasing the VT-Gas flow rate momentarily. This added flow seems to get the heavy tubes out smoothly. Cheers, Rich Shoemaker ----------------------------------------------------------------------- Dear Rudi, We had the similar problem with one of dozen probeheads in our laboratory, namely with 5 mm C/H dual probehead for ancient WM250. It was donated by Bruker company, and was the second hand probehead. Insert, most thin tube (6.0 mm in, 6.5 mm out) was broken every month. We used the same standard sample tubes on every of our 4 spectrometers, the same blue sample rotors (light), but inserts were broken only in one probehead. After 3d broken insert I removed cover of probehead and investigate it more attentively. It was found that both Dewar outer tube and middle glass tube (10 mm out) were slightly shorter than it should be (approximately 0.1-0.2 mm). So upper ceramic disk was supported primary by most thin internal tube and this tube was permanently under small stress. Any additional impact of sample tube brakes this stressed insert. To prevent this I made middle 10 mm tube from standard 10 mm sample tube some longer. Now namely this tube holds upper ceramic disk and insert is broken only one time per 2-3 years, i.e. approximately 1 time per 30000 samples. Hope it will help you, Yuri Strelenko. P.S. I invite you to visit our NMR site: http://nmr.ioc.ac.ru/fequip.htm -- ********************************************************************* | Dr. Yuri A. Strelenko | | | N.D.Zelinsky Institute | Fax (7-095) 135 5328 | | of Organic Chemistry, | Tel (7-095) 135 9094 | | Leninsky prospect 47, | e-mail strel_at_nmr1.ioc.ac.ru | | 117913 Moscow B-334, | | | Russia | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ----------------------------------------------------------------------- Dear Rudi, Once the air is stopped to allow sample insertion, on my system the air is simply allowed to leak out out of a pinhole in the air tube at the top of the magnet. I reckon if you made this hole smaller the tube may then drop more slowly and give a gentle landing. The Ceramic spinner is heavy and sometimes the rubber collar that holds the tube is loose, try tightening this somehow, so the tube cannot slip in the spinner as it crash lands at tthe bottom. Good luck, Mo ----------------------------------------------------------------------- Hi Rudi, We've got 3 Brukers here (AMX250 with scm shim, DPX300 with BOSS II and DRX400 with BOSSII). The 250 + 300 use QNP 5mm probes ( 250 with BACS sample changer) on both these machines J.Youngs valve tubes have been used -sporadically- and the only problem we encounter is difficulty spinning (even when our glassblower has shortened the length of the tubes)-we have the air supply going into the spectrometers at _at_ 7 bar (BRUKER recommend a min of 5), but I still flinch when the tube goes in as the landing isn't exactly soft. The story is the same on our 400 for the QNP, TXI (both 5mm) and VSP(10mm) probes - although Youngs tubes are less frequently used on this machine. Some users here have taken to buying in just the valve and then getting an nmr tube glassblown on -although they need to be pyrex to get a decent 'weld'. This doesn't seem to change the performance, but may be a way to reduce the overall tube weight. I can't remember the exact grade tube used for welding -but they were Wilmad tubes, I can dig out the details if you want, drop me a line if you need them. Sorry I can't be more helpful, hope you get this sorted asap Cheers Gerry Griffith ==================*****=================== Gerald Griffith Experimental Officer Department of Chemistry University of Leicester University Road Leicester LE1 7RH UK tel:(0116) 2522112 fax:(0116) 2523789 e-mail: gag3_at_le.ac.uk ----------------------------------------------------------------------- Rudi-- We experienced this problem with a triple probe, but it happened after the sample had been in the probe for quite awhile (days). Also, it was a protein sample and therefore not spinning. I don't recall if we were using a ceramic spinner or plastic at the time. The problem never reoccurred after replacement. tracy Tracy M. Handel Associate Professor MCB: Stanley/Donner ASU 229 Stanley Hall #3206 University of California Berkeley, CA 94720-3206 phone: 510-643-9313 fax:510-643-9290 ----------------------------------------------------------------------- Dear Rudi J Young tubes aren't in use around here, so they're not a problem I'm facing with our present machines. However, back in the days when I was a PhD student (some time ago) I worked in an organometallics group (using Bruker hardware) and we frequently used the Young tubes. To cut a long story short, we did indeed have trouble with the tubes. While we did not find the inserts shattering/cracking (as you pointed out the old inserts were a little more robust) we did find evidence of the inserts scoring toward the base. The problem was tracked to the tubes tilting off axis during spinning although we were uncertain whether the damage was done initially or continuously (initially would be the preferred bet on a system with good gas pressure regulation). Our solution at the time was (i) to shorten the tubes (as you suggested above) (ii) run non-spinning whenever reasonably possible and (iii) limit Young tube work to our least valuable probes (the tubes weren't of sufficient spec to merit using higher res spec probes anyway). I'll be interested to see if any Varian users report problems - I suspect that the beefier Varian spinners may result in a more favourable centre-of-gravity for the tube/spinner assembly and hence the tubes may not be a problem on those systems. Kind regards SueB Dr Sue Boyd Research Fellow & Manager Griffith University Magnetic Resonance Facility School of Science, Griffith University Nathan QLD, Australia, 4111 Ph 61 7 3875 7636 Fax 61 7 3875 7656 Alternate Email: nmr-manager_at_mailbox.gu.edu.au ----------------------------------------------------------------------- Hello Rudi, I am very pleased to be able to tell you that with our 6 week old new Bruker Avance 400 with Bruker Ultrashield magnet, we are now able to use Youngs tubes with our BACS 60 sample changer and normal blue spinners with no problems of bobbing, spinning or anything else (so far!), something I would not have dreamed of doing with our older systems. The design at the top of the rt bore, and the air flow etc must have been changed. I have not had any broken glassware problems in the past but have found with older magnets that the ceramic spinner is necessary and two people, one to hold the tube on the air cushion to stop it bobbing around and the second to operate the sample lift! regards Jane ***************************************************** Jane E. Hawkes, |email jane.hawkes_at_kcl.ac.uk NMR Service Manager, | Dept. of Chemistry, | Kings College, |tel: 020 7848 2074 (University of London), | Strand, | LONDON, WC2R 2LS, UK. |fax: 020 7848 2810 ***************************************************** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Rudi Nunlist Voice: (510) 642-6407 FAX: (510) 642-8369 University of California Email: nmrlab_at_purcell.cchem.berkeley.edu College of Chemistry NMR Facility Berkeley, CA 94720-1460 Personal email: rnunlist_at_purcell.cchem.berkeley.edu www.cchem.berkeley.edu/College/Facilities/nmr =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=Received on Mon Nov 06 2000 - 15:27:38 MST
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