Patent Application
20120194194
This application is generally related to sample containers for placing a sample for measurement of a property of the sample in an instrument, and more particularly, to sample tubes and closures for Nuclear Magnetic Resonance (NMR) samples.
Nuclear Magnetic Resonance spectroscopy is widely used in chemical studies for structure determination as well as presence, absence or concentration of a particular component in a sample. An NMR spectrum of a sample is generally determined by placing the sample in an elongate sample tube, placing the tube containing the sample in the field of a powerful magnet and selectively irradiating the sample with preselected radiofrequency signals and recording the effects of these signals on the sample. The sample tubes are formed from glass and are supplied in several sizes ranging from diameters of 1 mm to about 10 mm with lengths of about four inches to about seven inches long. The resolution of the spectrometer may be adversely affected by asymmetries in the sample tube and its placement within the magnetic field and irradiation coils. Accordingly, users of NMR spectrometers seek sample tubes and holders that minimize asymmetry.
In an effort to “average-out” sample asymmetry, some spectrometers axially spin samples on which the spectrum is being determined. More recently, NMR spectrometers have the capability to average-out some sample asymmetry electronically without spinning, but sample placement and positioning in the sample chamber is still important to optimize the resolution of the spectrometer. These more recent NMR spectrometers also utilize the tube closure to suspend the sample axially in the sample chamber. Thus, tube closures, or caps, need to do more than just close the tube. When the samples are not spun, the coaxiality of the outer diameter, the closure and the inside diameter of the tube, if not consistent and precise, may adversely effect the quality of the spectrum obtained.
In many cases, the materials whose NMR spectrum is being determined are derived from expensive and difficult to repeat studies. Accordingly, if a sample is lost or degraded because of a malfunction of the sample closure or the tube, the user may experience a substantial and expensive delay in their study. Thus, although there are many types of NMR sample systems and tube closure devices available, there is still a need for an NMR sample system and closure which is reliable, simple to use and allows the user of an NMR spectrometer to fully utilize the resolution capability of the spectrometer and ensure that the closure has been fully seated on the NMR tube. This is especially the case where automated sample handling equipment is employed. Such a system and closure is disclosed herein.
Embodiments of the invention are directed to kits comprising a package, at least one NMR tube and at least one closure. The package has a support structure adapted to contain and separate elongate articles. The at least one NMR tube comprises an elongate cylindrical body with an open proximal end and a band around an outside of the cylindrical body. The band is positioned adjacent the open proximal end and has a width extending along a length of the elongate cylindrical body. The at least one closure is configured to slidably engage the outside of the elongate cylindrical body so that when the closure is fully placed on the NMR tube, a distal end of the closure extends a length along the cylindrical body and is within about the width of the band.
In some embodiments, when the closure is fully placed on the NMR tube, the distal end of the closure is about equal to a proximal edge of the band. In detailed embodiments, when the closure is fully placed on the NMR tube, the closure covers a portion of the band. In specific embodiments, wherein when the closure is fully placed on the NMR tube, the distal end of the closure is about equal to a distal edge of the band.
Additional embodiments of the invention are directed to methods of using an NMR tube. A closure having a hollow bore in a distal end is placed over an open proximal end of an NMR tube having an elongate cylindrical body with an outer diameter and a band around an outside surface of the elongate cylindrical body. The band has a width and is placed adjacent the open proximal end. The hollow bore of the closure has an diameter about equal to or lesser than about the outer diameter of the elongate body. A distally directed force is applied to the closure to cause the hollow bore to slide along the outside surface of the elongate cylindrical body to a length from the open proximal end, so that when the closure is fully placed on the NMR tube, the distal end of the closure is within about the width of the band.
In some embodiments, resistance to the distally directed force remains about constant throughout pushing the closure along the elongate cylindrical body from the open proximal end until the closure cannot be pushed further. In various embodiments, resistance to the distally directed force varies throughout pushing the closure along the elongate cylindrical body from the open proximal end until the closure cannot be pushed further.
In one or more embodiments, after the closure is fully placed on the NMR tube, the distal end of the closure is adjacent a proximal edge of the band. In detailed embodiments, after the closure is fully placed on the NMR tube, the distal end of the closure covers at least a portion of the band. In specific embodiments, after the closure is fully placed on the NMR tube, the distal end of the closure covers the entire band.
Some embodiments of the method further comprise adding a sample to the NMR tube before placing the closure over the proximal open end of the NMR tube. In detailed embodiments, the sample is added to the NMR tube through an opening in the closure after the closure has been fully placed on the NMR tube. The opening extends axially through the closure so that after the closure has been fully placed onto the NMR tube, a sample can be placed into the NMR tube through the opening. In specific embodiments, the opening comprises a septum. In one or more embodiments, the NMR tube is placed into a sample spinner.
In some embodiments, the at least one closure has a color and the band on the at least one NMR tube is colored. In detailed embodiments, the color of the closure is the same as the color of the band. In specific embodiments, the color of the closure is different than the color of the band.
The present invention also contemplates apparatus that includes a NMR cylindrical tube having a closed end and an open end, a cap having a hollow bore sized to securely fit over the open end of the NMR cylindrical tube and a band around the outside of the NMR cylindrical tube. The band is positioned adjacent the open end of the NMR cylindrical tube such that when a top portion of the hollow bore of the cap touches the open end of the NMR cylindrical tube, at least a portion of the band is visible.
Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.
Reference throughout this specification to “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment”, means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “in an embodiment”, in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.
In this specification and the appended claims, the term “proximal” refers to the direction away from the closed end of the sample tube and the term “distal” refers to the direction toward the closed end of the sample tube.
Referring to
The length L1, or distance between the proximal edge 31 of the band 28 and the open proximal end 12 of the sample tube 14, can vary depending on, amongst others, the dimensions of the sample tube 14 and closure 10 associated with the sample tube. Generally, the length L1 is in the range of about 0 mm to about 15 mm. In detailed embodiments, the length L1 is greater than about 1 mm, 2 mm, 3 mm, 4 mm or 5 mm. In some embodiments, the length L1 is less than about 14 mm, 13 mm, 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, 7 mm or 6 mm. In various embodiments, the length L1 is in the range of about 1 mm to about 10 mm, or in the range of about 2 mm to about 9 mm, or in the range of about 3 mm to about 8 mm, or in the range of about 4 mm to about 7 mm, or in the range of about 5 mm to about 7 mm, or in the range of about 6 mm to about 7 mm. In specific embodiments, the length L1 is in the range of about 6.4 mm to about 6.5 mm.
The length L3 (or width W) can vary depending on, amongst others, the length L1, the sample tube 14 dimensions and the length L2. In various embodiments, the length L3 (width W) of the band 28 is in the range of about 0.25 mm to about 5 mm or in the range of about 0.5 mm to about 4 mm, or in the range of about 0.75 mm to about 3 mm, or in the range of about 1 mm to about 2.5 mm. In specific embodiments, the width W of the band 28 is about 1.25 mm.
Additional embodiments of the invention are directed to methods of using an NMR tube. An exemplary method is embodied by
As shown in the embodiment of
In the embodiment shown in
Adding a sample to the tube can be accomplished in many ways using various devices, instruments and automated systems. In one or more embodiments, a sample is added to the NMR sample tube 14 before placing the closure 10 over the open proximal end 12 of the NMR sample tube 14. This is a common technique where the sample tube 14 is filled with sample prior to capping.
It is also possible to fill the sample tube 14 after placing the closure 10 over the open proximal end 12 of the sample tube 14.
In detailed embodiments, resistance to the distally directed force remains about constant throughout movement of the closure 10 along the elongate cylindrical body 15 from the open proximal end 12 until the closure 10 cannot be pushed further. This may be the case where the hollow bore 20 of the closure 10 has a substantially uniform profile (i.e., cylindrical). When the hollow bore 20 has a substantially uniform profile, the diameter of the hollow bore 20 is about equal to or lesser than the outside diameter of the NMR sample tube 14. If the fit of the closure 10 is too loose, the closure will not function properly. If the fit of the closure 10 is too tight, the closure will not readily slide on the sample tube 14 and may cause the sample tube 14 to break.
In specific embodiments, resistance to the distally directed force varies throughout pushing the closure 10 along the elongate cylindrical body 15 from the open proximal end 12 until the closure 10 cannot be pushed further. Variable resistance may be felt where the closure 10 has a hollow bore 20 with a non-uniform profile.
The color of the closure 10 and the band 28 can be configured as desired. In some embodiments, the closure 10 and the band 28 have the same color. In detailed embodiments, the closure 10 has a different color than the band 28. This may help the user see the band when the closure 10 approaches the band 28, or slides over the band 28. In specific embodiments the closure is red and the band is white. In some embodiments, one or more of the closure and the band are blue.
In another detailed embodiment, as shown in
In some embodiments of the closure of the invention, the closure may be formed from a solid rod of a polymeric material such as polytetrafluoroethylene (PTFE) or other substantially chemically inert materials having similar properties. The use of PTFE as a material is facilitated by shaping the rod into the desired dimensions with a computer numerical controlled (CNC) automated lathe apparatus. Once the CNC apparatus is properly set-up, it can repeatedly efficiently produce the closure of the invention with a high degree of accuracy and precision. For other applications, injection molding techniques using other polymeric materials may be utilized, but many polymeric materials suitable for injection molding may not have the same degree of solvent resistance and dimensional stability as PTFE. Additionally, PTFE has sufficient resiliency that the closure will deflect sufficiently at central portion 24 to allow for some variation in NMR tube outside diameter. For example, tubes of European manufacture may have a slightly larger nominal outside diameter for a particular size than tubes manufactured in North America.
NMR sample tubes 14 can be made from a variety of materials. Typically, sample tubes are formed from a vitreous material, generally various types of glass, e.g., soda-lime, borosilicate, quartz, and the like. In some applications, a polymeric material may also be used. The band 28 can be applied to any of the materials used in the manufacture of NMR tubes.
In summary, in accordance with one of the aspects of the present invention, laboratory apparatus is provided. A NMR cylindrical tube having a closed end and an open end is provided. A cap having a hollow bore sized to fit securely over the open end of the NMR cylindrical tube is also provided. The NMR cylindrical tube has a band around the circumference of the NMR cylindrical tube. The band is positioned adjacent the open end of the NMR cylindrical tube such that when a top portion of the hollow bore of the cap touches the open end of the NMR cylindrical tube, at least a portion of the band is visible.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. In particular, those skilled in the art will know how to make appropriate changes to the dimensions of the below-described closure consistent with the invention and needs of the user. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents.
