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| Fig. 1.
New Era sample cell (7.5x5.5 mm outside, a little over 6x4 mm inside, #SK-190505-1) with typical sample below. |
1) Rectangular containers:
The cross section of the inner sample solenoid in our low-E probes is 7.5x5.5 mm, and its
length is 11 mm. This particular coil size evolved around dimensions of
rectangular glass tubes that were used in our laboratory. New Era Enterpises now produces such thin-wall glass cell, shown in Fig. 1.
The outer dimensions of the cell are matched
closely to the sample opening in the probe. No glass grinding or cutting is
required during sample preparation. The cells are available with one or with two open ends, costing
$11 to $20 per piece depending on quantity, from
New Era Enterprises, Inc.
P.O. Box 747, Vineland, NJ, USA, Tel. +1-800-821-4667
Contact: Frank Bosco (E-mail: fbosco@newera-nmr.com)
Part number SK-190505-1
2) Glass slides for alignment:
For preparation of mechanically oriented samples, users of our facilities utilize glass slides of 5.7x12.0x0.065 mm that fit inside above rectangular cells.
Somewhat thinner 30-50 um slides can be purchased but at a significantly higher price. Thinner slides allow more sample material and hence increase S/N ratio.
Paul Marienfeld GmbH & Co. KG
Am Wollerspfad 4, 97922 Lauda-Konigshofen, Germany
Tel: 49-9343-6272-26, fax: +49-9343-6272-25
Contact: Harry Marienfeld (E-mail: www.marienfeld-superior.com)
3) Sealing the sample:
A. Once the sample stack is inside the glass cell and ready for the experiment, the open end of
the cell can be sealed with beeswax, which holds the seal fairly well. Beeswax, wax pen and other
supplies are available from Hampton Research (see contact below). Use "Capillary Wax" for sample
tube sealing and "Wax Pen" for wax melting. Bees wax does not seal well against liquids such as bicelle solution.
B. Alternative sealing plug has just been developed in our lab for rectangular cells that can hold even liquids.
It is easy to use and quite inexpensive. It will be posted here shortly.
Hampton Research
34 Journey, Aliso Viejo, CA 92656-3317
Tel: +1-949-425-1321, www.hamptonresearch.com
E-mail: info@hrmail.com
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| Fig. 2.
New Era 5.0 mm sample tubes sealed with the rubber plunger. |
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| Fig. 3.
Bicelle sample containers with specially designed bubble-free plugs for 5.0 and 6.5 mm tubes. |
1) Glass tubes:
We use 5.0 mm and 6.5 mm OD glass tubes with flat bottom, purchased from the same vendor who makes flat cells.
The 6.5 mm container holds almost twice the sample of the 5.0 mm one and is therefore beneficial for the applications on dilute samples.
New Era Enterprises, Inc.
P.O. Box 747, Vineland, NJ, USA, Tel. +1-800-821-4667
Contact: Frank Bosco (E-mail: fbosco@newera-nmr.com)
Part numbers NE-RG5-15-FB or NE-RG6.5-20-FB.
2) Rubber plugs — 5.0 mm size only:
In this preparation, the sample is filled to 8-9 mm length and plugged with the rubber plunger (Fig. 2).
The rubber plunger is taken off the 1 mL Becton Dickinson (BD) syringes. Such packaging was introduced to us by the lab of Prof. Stan Opella at UCSD.
Standard 5 mm solution NMR tubes will fit in the coil as well.
However, it is harder to limit sample to the homogeneous region of the coil within NMR tube.
Also, NMR tubes would have to be cut short (they are more fragile), and their end is rounded.
Keep in mind that the plunger will produce background signal in 13C detection experiments.
BD Medical – Pharmaceutical Systems
1 Becton Drive, MC407, Franklin Lakes, NJ 07417, USA
Tel. +1-201-847-4017 (or at www.bd.com)
1mL Sub-Q26G 5/8, Reorder number 309597.
3) Bubble-free plugs — 5.0 and 6.5 mm tubes:
A special fluorocarbon plug system was developed to eliminate bubbles during the sample preparation and to allow for the background-free 13C experiments.
These plugs fit New Era 5.0 and 6.5 mm tubes (Fig. 3). This plug system is easier to use and ensures consistent amount of sample during each fill.
The plugs allow for easy sample positioning inside the RF coil and thus help the user in avoiding electric field hotspots near the edges.
We are working with the vendor to have these plugs commercially available in the summer of 2008.
In the meantime, we have some of them in-house, available for the external users.
Vendor to be anounced...
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