Modification of air/fluid flow around nuclear magnetic resonance probe and methods of use
In an embodiment of the present invention, by accelerating the variable temperature air, the cooling/heating caused by thermal radiation of the sample in the NMR field can be more efficiently removed thereby efficiently eliminating or minimizing natural convection in the sample. In an embodiment of the present invention, by passing the air/fluid flow through a restricted section prior to the air/fluid flow contacting the sample, the cooling/heating caused by thermal radiation of the sample in the NMR field can be more efficiently removed thereby efficiently eliminating or minimizing natural convection in the sample. In various embodiments of the invention, by passing the air/fluid flow through a restricted section prior to the air/fluid flow contacting the sample, the resulting NMR spectra show an increased performance, and/or line shape and/or resolution.
1 . A NMRI (Nuclear Magnetic Resonance Instrument) adapted to detect a resonance of at least a nucleus from a plurality of nuclei of a sample molecule, comprising:
(i) a parent coil circuit comprising a parent coil and a sample coil circuit comprising a sample coil, where the parent coil comprises one or both a radio frequency coil and a microwave frequency coil;
(ii) a bore tube;
(iii) a sample cell comprising a length adapted for holding the sample molecule, where the sample cell is adapted to be inserted into the bore tube;
(iv) a gas supply adapted to provide a gas flow to the sample cell; and
(v) a RSVTC (Restricted Section Variable Temperature Chamber) comprising an entrance with a first diameter, a reduced section with a second diameter, and an exit with a third diameter, where the RSVTC is in fluid connection with the gas supply, where the RSVTC is in fluid connection with the bore tube, where the gas flow is adapted to pass through the RSVTC into the bore tube and contact the sample cell, where a plurality of gas molecules passing through the RSVTC are either heated/cooled entering into the bore tube, where the NMRI is adapted to apply a magnetic field with the parent coil to the sample cell, where the NMRI is adapted to detect a NMRI mode of at least one of the plurality of nuclei of the sample molecule in the sample coil, where the gas supply contacting the sample cell cause the sample molecule to be heated/cooled.
2 . The NMRI of claim 1 , where the third diameter is less than the first diameter.
3 . The NMRI of claim 1 , where the second diameter is less than the first diameter.
4 . The NMRI of claim 1 , where the RSVTC reduces turbulent flow of the plurality of gas molecules toward a laminar flow.
5 . The NMRI of claim 1 , where the RSVTC reduces transition state flow of the plurality of gas molecules toward a laminar flow.
6 . The NMRI of claim 1 , where the RSVTC changes the plurality of gas molecules entering the bore tube from a turbulent flow toward a transition state flow.
7 . The NMRI of claim 1 , where the RSVTC changes the plurality of gas molecules entering the bore tube from a turbulent flow toward a laminar flow.
8 . The NMRI of claim 1 , where the RSVTC changes the plurality of gas molecules entering the bore tube from a transition state flow toward a laminar flow.
9 . The NMRI of claim 1 , where the plurality of gas molecules entering the bore tube are a transition state flow.
10 . The NMRI of claim 1 , where the plurality of gas molecules entering the bore tube are a laminar flow.
11 . The NMRI of claim 1 , where the plurality of gas molecules at the exit are between:
a lower limit of approximately 1600 Reynolds number; and
an upper limit of approximately 2400 Reynolds number.
12 . The NMRI of claim 1 , where the plurality of gas molecules at the exit are between:
a lower limit of approximately 2000 Reynolds number; and
an upper limit of approximately 2300 Reynolds number.
13 . The NMRI of claim 1 , where the RSVTC changes an average thermal gradient of sample molecules to between:
a lower limit of approximately 0.01° C.; and
an upper limit of approximately 0.05° C.
14 . The NMRI of claim 1 , where the RSVTC reduces a thermal gradient of sample molecules along the length of the sample cell to between:
a lower limit of approximately 0.01° C./mm; and
an upper limit of approximately 0.05° C./mm.
15 . The NMRI of claim 1 , where the second diameter is between:
a lower limit of approximately thirty (30) percent of the first diameter; and
an upper limit of approximately ninety (90) percent of the first diameter.
16 . The NMRI of claim 1 , where the second diameter is between:
a lower limit of approximately sixty (60) percent of the first diameter; and
an upper limit of approximately eighty (80) percent of the first diameter.
17 . The NMRI of claim 1 , where the plurality of gas molecules passing through the RSVTC are cooled when thermal radiation is heating the sample molecules and the plurality of gas molecules passing through the RSVTC are heated when thermal radiation is cooling the sample molecules.
18 . The dual RSVTC (Restricted Section Variable Temperature Chamber) comprising:
an entrance with a first diameter;
a reduced section with a second diameter;
a plurality of channels; and
a plurality of exits, where the dual RSVTC is adapted to connect with a gas flow comprising a plurality of gas molecules, where the dual RSVTC is adapted to connect to a bore tube such that passage of the plurality of gas molecules through the dual RSVTC deliver the plurality of gas molecules in the bore tube and contact a sample cell of a length of a NMR (Nuclear Magnetic Resonance) instrument, where the plurality of gas molecules passing through the dual RSVTC are either heated or cooled entering into the bore tube, where the plurality of gas molecules contacting the sample cell cause at least a plurality of sample molecules in the sample cell to be heated/cooled.
19 . A method of detecting a NMR (Nuclear Magnetic Resonance) resonance of at least a nucleus from a plurality of nuclei of a sample molecule using a gas flow through a RSVTC (Restricted Section Variable Temperature Chamber) to heat/cool the sample molecule, where the RSVTC comprises an entrance with a first diameter, a reduced section with a second diameter, and an exit with a third diameter, comprising:
(i) selecting a parent coil circuit comprising a parent coil and a sample coil circuit comprising a sample coil;
(ii) selecting a sample;
(iii) loading a plurality of sample molecules into a sample cell, where the sample cell comprises a length;
(iv) introducing the sample cell into a bore tube;
(v) applying a magnetic field with the parent coil to the sample cell;
(vi) exciting with the sample coil the plurality of sample molecules with one or both a radio frequency field and a microwave frequency field at a Larmor frequency to allow the parent coil to detect the resonance of the nucleus; and
(vii) passing a flow of a gas through the RSVTC into contact with the sample cell to heat/cool the sample molecules.
20 . The method of claim 19 , where the flow of a gas through the RSVTC into contact with the sample cell cools the sample molecules when thermal radiation is heating the sample molecules, where the flow of a gas through the RSVTC into contact with the sample cell heats the sample molecules when thermal radiation is cooling the sample molecules.