<HTML dir=ltr><HEAD><TITLE>Re: [RASMB] 20 mm path cells [was: peptide in DMSO]</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Tom: we would certainly be interested.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2>For most of our work the epon centrepieces are fine.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2>Steve</FONT></DIV>
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<DIV id=idSignature55709 dir=ltr><PRE><HR tabIndex=-1><FONT face=Tahoma size=2><B>From:</B> Tom Laue [mailto:tml@cisunix.unh.edu]<BR><B>Sent:</B> Wed 30/04/2008 15:18<BR><B>To:</B> Kristian Schilling<BR><B>Cc:</B> jphilo@mailway.com; 'Harding Stephen'; rasmb@server1.bbri.org; brett.austin<BR><B>Subject:</B> Re: [RASMB] 20 mm path cells [was: peptide in DMSO]<BR></FONT><BR></PRE></DIV>
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<P><FONT size=2>Hi-<BR>If there is sufficient interest, Spin Analytical will make epon<BR>(charcoal or aluminum) versions of the 20 mm centerpieces. We currently<BR>make 1.2, 3 and 12 mm centerpieces.<BR>Best wishes,<BR>Tom<BR><BR>Kristian Schilling wrote:<BR>> John,<BR>><BR>> I have been planning for years to post some information on our<BR>> centerpieces on the website. Perhaps I should eventually get back to<BR>> that...<BR>><BR>> The initial point about our centerpieces was Dr. Mueller's (Bayer)<BR>> efforts years ago to persuade Beckman to offer titanium centerpieces,<BR>> inert to acids, bases, and organic solvents. After this did get<BR>> nowhere for years, it was him and Helmut Coelfen who eventually found<BR>> workshops here in Germany capable of manufacturing standard 12 mm<BR>> centerpieces with sufficient surface smoothness.<BR>><BR>> When I opened up this business in 2000 I was in need of these<BR>> centerpieces as well (I encountered them in Helmut's lab during my PhD<BR>> work) which made three of us. We then agreed that for the future I<BR>> coordinate the making of centerpieces and gradually I have been<BR>> providing them to other users as well.<BR>><BR>> In the course of the recent years, I have been extending the scope to<BR>> 20mm, 3mm and 1.5mm centerpieces; we have also made six channel but I<BR>> was not really happy with those - they tended to leak from one sector<BR>> to the other. While we were at it, I have also been making housings,<BR>> window holders, screw rings, and plug screws. One motivation was to<BR>> switch to metric plug screws that do not wear off as quickly as the<BR>> brass inch screws made by Beckman. Another was to have suitable<BR>> housings for longer and shorter centerpieces. A third was to save money.<BR>><BR>> It is correct that there is a balance issue. It is already with<BR>> 12-mm-centerpieces that the Beckman weight set cannot balance the<BR>> additional weight. It has been attempted to make screws from heavy<BR>> metals but those are still too long and may stand proud of the thread.<BR>> So we make titanium counterbalances as well, and they can be balanced<BR>> with the Beckman weight set. They have the slit masks for radial<BR>> calibration.<BR>><BR>> Beckman once stated (in the course of Dr. Mueller's correspondence)<BR>> that they see no security issue concerning the rotor - the additional<BR>> weight is no problem. However, their policy is that their warranty<BR>> does not cover rotors and instruments if any non Beckman cell material<BR>> is used. I tell this all users that have purchased cell components<BR>> from us. I might add that we give no warranty either, but we have been<BR>> using these cells at full rated speed for years.<BR>><BR>> One point you asked about the 20-mm-cells (where our housings are<BR>> required, of course): No, they do not protude from the rotor hole. But<BR>> there is not much left. For sure, we would have come to yet longer<BR>> cells, as low concentrated samples are frequent. 20 mm is the best one<BR>> can do.<BR>><BR>> And yes, the standard centerpieces fit into the Beckman cell housings,<BR>> and they require the same gaskets as do the aluminum centerpieces.<BR>> Needless to say that we have found a workshop for the gaskets as well.<BR>><BR>> Best wishes,<BR>> Kristian<BR>><BR>><BR>> At 08:30 29.04.2008 -0700, John Philo wrote:<BR>>> Steve (or Kristian)<BR>>><BR>>> I for one had not heard about these 20 mm pathlength cells, and I<BR>>> could find<BR>>> nothing about them on the Nanolytics web site. Could you elaborate a bit<BR>>> about the configuration? Do the housings actually project out of the<BR>>> rotor?<BR>>> Other than a special housing and centerpiece, are other parts<BR>>> (centerpiece<BR>>> gaskets, screw rings, windows, window holders, etc.) the same? Is a<BR>>> different counterbalance required to achieve balance?<BR>>><BR>>> John<BR>><BR>><BR>><BR>> =================================<BR>> Nanolytics<BR>> Gesellschaft fuer Kolloidanalytik mbH<BR>> Dr. Kristian Schilling<BR>><BR>> Am Muehlenberg 11<BR>> 14476 Potsdam<BR>> Tel.: +49 331 5818360<BR>> Fax: +49 331 5818361<BR>><BR>> e-mail: schilling@nanolytics.de<BR>> Internet: www.nanolytics.de<BR>> <BR>><BR>> _______________________________________________<BR>> RASMB mailing list<BR>> RASMB@rasmb.bbri.org<BR>> <A href="http://rasmb.bbri.org/mailman/listinfo/rasmb">http://rasmb.bbri.org/mailman/listinfo/rasmb</A><BR>><BR><BR>--<BR>Department of Biochemistry and Molecular Biology<BR>University of New Hampshire<BR>Durham, NH 03824-3544<BR>Phone: 603-862-2459<BR>FAX: 603-862-0031<BR>E-mail: Tom.Laue@unh.edu<BR>www.bitc.unh.edu<BR>www.camis.unh.edu<BR><BR></FONT></P></DIV></BODY><br/>
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