Deuterium Lock - Revision history

Aringh at 16:30, 9 December 2009

2009-12-09T16:30:13Z

← Older revision		Revision as of 16:30, 9 December 2009
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	Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.		Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.

	The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require ~~using~~ hardware autoshim during long-term experiments.		The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require use of hardware autoshim during long-term experiments.

	== Finding Lock Signal Automatically ==		== Finding Lock Signal Automatically ==
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	== Temperature Dependence ==		== Temperature Dependence ==

	The position of the water line in 1H or 2H spectra has a strong dependence on temperature. Since ~~locking matches~~ the deuterium resonance of water to a predefined frequency, <tt>z0</tt> will be different at different temperatures.		The position of the water line in 1H or 2H spectra has a strong dependence on temperature. Since lock tries to match the deuterium resonance of water to a predefined frequency, <tt>z0</tt> will be different at different temperatures.

	It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).		It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).
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	Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.		Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.

	To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) ~~stay the same~~, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation		To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) remain unchanged, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation

	== Resetting Lock Frequency ==		== Resetting Lock Frequency ==
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	<br>		<br>

	== Working with Bruker Instruments ==		== Working with Bruker Instruments ==

	The following description pertains to systems with Bruker TopSpin v. 2.0 and higher.		The following description pertains to systems with Bruker TopSpin v. 2.0 and higher.

	After inserting the sample, the user opens the lock display using the command:		After inserting the sample, the user opens the lock display using the command:
	<pre>lockdisp		<pre>lockdisp
	</pre>		</pre>
	This open the lock display (see below).  If unlocked, one observes the ringing signal (left); if locked, then the lock signal is a flat trace (right).		This open the lock display (see below).  If unlocked, one observes the ringing signal (left); if locked, then the lock signal is a flat trace (right).

	[[Image:~~Lock_unlocked~~.jpg\|400px]][[Image:~~Lock_locked~~.jpg\|400px]]		[[Image:Lock unlocked.jpg\|400px]][[Image:Lock locked.jpg\|400px]]

	With the system unlocked:		With the system unlocked:

	*Manually ~~adust~~ the "Field" and "Phase" settings on the BSMS panel, to make the unlocked signal symmetric and centered within the display.		*Manually adjust the "Field" and "Phase" settings on the BSMS panel, to make the unlocked signal symmetric and centered within the display.
	*Then press the "lock" button on the BSMS panel to lock on deuterium.		*Then press the "lock" button on the BSMS panel to lock on deuterium.

	With the system locked:		With the system locked:

	*Manually optimize the shims (BSMS panel) by optimizing the height of the lock signal prior to automated shimming routines.		*Manually optimize the shims (BSMS panel) by optimizing the height of the lock signal prior to automated shimming routines.

			<br>

			<br>


	== ==		== ==

	<br> -- Main.AlexEletski - 24 Jan 2007		<br> -- Main.AlexEletski - 24 Jan 2007

Jma at 18:03, 4 December 2009

2009-12-04T18:03:25Z

← Older revision		Revision as of 18:03, 4 December 2009
Line 1:		Line 1:
	The lock system keeps the spectrometer operating at a constant net magnetic field. It compensates for the drift of the superconducting magnet's field and other instabilities. The current in the		The lock system keeps the spectrometer operating at a constant net magnetic field. It compensates for the drift of the superconducting magnet's field and other instabilities. The current in the <tt>z0</tt> coil is adjusted so that the lock resonance matches a predefined frequency <tt>lockfreq</tt> . Before activating the lock system you have to find the lock resonance.
	<tt>z0</tt>
	coil is adjusted so that the lock resonance matches a predefined frequency
	<tt>lockfreq</tt>
	. Before activating the lock system you have to find the lock resonance.

	For detailed information on locking you sample see		For detailed information on locking you sample see
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	Adjust <tt>z0</tt> to locate the lock resonance. You may increase lock power and gain to see the signal better. When manually adjusting <tt>z0</tt> the following rule holds: the closer you are to the resonance, the fewer sinusoid "beats" you see. When on-resonance you should see a straight line. The figures below show examples from a typical locking process.		Adjust <tt>z0</tt> to locate the lock resonance. You may increase lock power and gain to see the signal better. When manually adjusting <tt>z0</tt> the following rule holds: the closer you are to the resonance, the fewer sinusoid "beats" you see. When on-resonance you should see a straight line. The figures below show examples from a typical locking process.

	[[Image:Lock a.jpg\|205x273px\|lock off-resonance]][[Image:Lock b.jpg\|205x273px\|lock closer to resonance]][[Image:Lock c.jpg\|205x273px\|lock on resonance]]'''<br>'''		[[Image:Lock a.jpg\|205x273px\|lock off-resonance]][[Image:Lock b.jpg\|205x273px\|lock closer to resonance]][[Image:Lock c.jpg\|205x273px\|lock on resonance]]'''<br>'''


			<br>

	Activate the lock system:		Activate the lock system:
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	Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.		Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.

	The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.		The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.

	== Finding Lock Signal Automatically ==		== Finding Lock Signal Automatically ==
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	It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).		It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).

	== Solvent dependence ==		== Solvent dependence ==

	Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.		Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.

	To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation		To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation

	== Resetting Lock Frequency ==		== Resetting Lock Frequency ==
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	<br>		<br>

	<br> -- Main.AlexEletski - 24 Jan 2007		== Working with Bruker Instruments ==

			The following description pertains to systems with Bruker TopSpin v. 2.0 and higher.

			After inserting the sample, the user opens the lock display using the command:
			<pre>lockdisp
			</pre>
			This open the lock display (see below).  If unlocked, one observes the ringing signal (left); if locked, then the lock signal is a flat trace (right).

			[[Image:Lock_unlocked.jpg\|400px]][[Image:Lock_locked.jpg\|400px]]

			With the system unlocked:

			*Manually adust the "Field" and "Phase" settings on the BSMS panel, to make the unlocked signal symmetric and centered within the display.
			*Then press the "lock" button on the BSMS panel to lock on deuterium.

			With the system locked:

			*Manually optimize the shims (BSMS panel) by optimizing the height of the lock signal prior to automated shimming routines.





			== ==

			<br> -- Main.AlexEletski - 24 Jan 2007

Alex: /* Resetting Lock Frequency */

2009-11-29T19:22:07Z

Resetting Lock Frequency

← Older revision		Revision as of 19:22, 29 November 2009
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	Locking requires setting <tt>z0</tt> so that the deuterium resonance of the solvent (D2O in protein NMR) matches the lock frequency <tt>lockfreq</tt> of the spectrometer. One day you may find that the lock resonance is beyond the operating range of <tt>z0</tt>. In this case it is necessary to reset <tt>lockfreq</tt> to a lower value. This parameter has to be changed on 500MHz, 600MHz and 750MHz instruments in Buffalo about once or twice a year depending on the field drift.		Locking requires setting <tt>z0</tt> so that the deuterium resonance of the solvent (D2O in protein NMR) matches the lock frequency <tt>lockfreq</tt> of the spectrometer. One day you may find that the lock resonance is beyond the operating range of <tt>z0</tt>. In this case it is necessary to reset <tt>lockfreq</tt> to a lower value. This parameter has to be changed on 500MHz, 600MHz and 750MHz instruments in Buffalo about once or twice a year depending on the field drift.

	Run <tt>config</tt> to open a spectrometer configuration window and key in the new frequency there, then type <tt>su</tt> to enable the new setting. Record this event in ~~your lab notebook~~ and inform ~~your colleagues~~. You must be running ~~Buffalo.~~VNMR as <tt>vnmr1</tt> to do that. Regular users~~, such as <tt>coldnmr</tt> on 600 MHz,~~ do not have permissions to modify configuration.		Run <tt>config</tt> to open a spectrometer configuration window and key in the new frequency there, then type <tt>su</tt> to enable the new setting. Record this event in the logbook and inform other users of the instrument. You must be running VNMR or VNMRJ as <tt>vnmr1</tt> users to do that. Regular users do not have permissions to modify configuration.

	There is always an issue of how big the change in <tt>lockfreq</tt> should be. Obviously, it should not be so small that you will have to do it again next week, and should not be too large that your <tt>z0</tt> is out of range in on the opposite side.		There is always an issue of how big the change in <tt>lockfreq</tt> should be. Obviously, it should not be so small that you will have to do it again next week, and should not be too large that your <tt>z0</tt> is out of range in on the opposite side.

	On both 600 MHz and 750 MHz spectrometers one unit of <tt>z0</tt> is equivalent to approximately 0.05 Hz. Since <tt>z0</tt> has a range of -32767 to 32767, <tt>lockfreq</tt> can be safely changed by about 2700 Hz.		For example, for both 600 MHz and 750 MHz spectrometers in Prof. Szyperski's lab one unit of <tt>z0</tt> is equivalent to approximately 0.05 Hz. Since <tt>z0</tt> has a range of -32767 to 32767, <tt>lockfreq</tt> can be safely changed by about 2700 Hz. Field drift rate of 600 MHz spectrometer was found to be ~315 <tt>z0</tt> units/day or ~16 Hz/day. The drift rate of 750 MHz is ~100 <tt>z0</tt> units/day or ~5 Hz/day. Therefore, <tt>lockfreq</tt> needs to be reset about twice a year on 600 MHz and once every year and a half on 750 MHz.

	Field drift rate of 600 MHz spectrometer was found to be ~315 <tt>z0</tt> units/day or ~16 Hz/day. The drift rate of 750 MHz is ~100 <tt>z0</tt> units/day or ~5 Hz/day. Therefore, <tt>lockfreq</tt> needs to be reset about twice a year on 600 MHz and once every year and a half on 750 MHz.

	'''DO NOT''' type something like <tt>lockfreq = 99.999</tt> at the prompt. This would only be valid until you restart VNMR or VNMRJ and is grossly confusing.		'''DO NOT''' type something like <tt>lockfreq = 99.999</tt> at the prompt. This would only be valid until you restart VNMR or VNMRJ and is grossly confusing.

Alex at 18:06, 11 November 2009

2009-11-11T18:06:14Z

← Older revision		Revision as of 18:06, 11 November 2009
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	Adjust <tt>z0</tt> to locate the lock resonance. You may increase lock power and gain to see the signal better. When manually adjusting <tt>z0</tt> the following rule holds: the closer you are to the resonance, the fewer sinusoid "beats" you see. When on-resonance you should see a straight line. The figures below show examples from a typical locking process.		Adjust <tt>z0</tt> to locate the lock resonance. You may increase lock power and gain to see the signal better. When manually adjusting <tt>z0</tt> the following rule holds: the closer you are to the resonance, the fewer sinusoid "beats" you see. When on-resonance you should see a straight line. The figures below show examples from a typical locking process.

	~~<img src="%ATTACHURLPATH%/lock_a~~.jpg~~" alt="lock_a~~.jpg~~" /> <img src="%ATTACHURLPATH%/lock_b~~.jpg~~" alt="lock_b.jpg" /> <img src="%ATTACHURLPATH%/lock_c.jpg" alt="lock_c.jpg" />~~		[[Image:Lock a.jpg\|205x273px\|lock off-resonance]][[Image:Lock b.jpg\|205x273px\|lock closer to resonance]][[Image:Lock c.jpg\|205x273px\|lock on resonance]]'''<br>'''


	'''Fig. 1''' a) LEFT: the lock window which shows a far-off <tt>z0</tt> to the lock frequency; b) MIDDLE: the lock window which shows a closer <tt>z0</tt> to lock frequency; and c) RIGHT: lock window which shows <tt>z0</tt> on the lock frequency.

	Activate the lock system:		Activate the lock system:

Alex at 17:58, 11 November 2009

2009-11-11T17:58:09Z

← Older revision		Revision as of 17:58, 11 November 2009
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	#Click in the '''Lock Scan''' button in the middle of the screen		#Click in the '''Lock Scan''' button in the middle of the screen

	[[Image:Vnmrj lock.png]]		[[Image:Vnmrj lock.png\|606x172px]]

	Make sure the the lock system is not activated:		Make sure the the lock system is not activated:

Alex at 17:45, 11 November 2009

2009-11-11T17:45:41Z

← Older revision		Revision as of 17:45, 11 November 2009
Line 27:		Line 27:
	#Click in the '''Lock Scan''' button in the middle of the screen		#Click in the '''Lock Scan''' button in the middle of the screen

	~~<img src="%ATTACHURLPATH%/vnmrj_lock~~.png~~" alt="vnmrj_lock.png" width='964' height='274' />~~		[[Image:Vnmrj lock.png]]

	Make sure the the lock system is not activated:		Make sure the the lock system is not activated:
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	Activate the lock system:		Activate the lock system:

	*In VNMR click on the '''LOCK:on''' button in the acquisition window; ~~%RED%~~ LOCK OFF ~~%ENDCOLOR%~~ should change to ~~%GREEN%~~ LOCKED ~~%ENDCOLOR%~~		*In VNMR click on the '''LOCK:on''' button in the acquisition window; <span style="color: red;"> LOCK OFF </span>  should change to <span style="color: green;"> LOCKED </span>
	*In VNMRJ check the '''Activate Lock''' checkbox		*In VNMRJ check the '''Activate Lock''' checkbox

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	Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.		Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.

	The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.		The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.

	== Finding Lock Signal Automatically ==		== Finding Lock Signal Automatically ==

Alex at 17:39, 11 November 2009

2009-11-11T17:39:39Z

← Older revision		Revision as of 17:39, 11 November 2009
Line 74:		Line 74:
	It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).		It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).

	== ==		== Solvent dependence ==

	Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.		Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.

	To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation		To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation

	== Resetting Lock Frequency ==		== Resetting Lock Frequency ==

Alex at 17:38, 11 November 2009

2009-11-11T17:38:31Z

← Older revision		Revision as of 17:38, 11 November 2009
Line 1:		Line 1:
	== '~~''Deuterium Lock System''' ==~~		The lock system keeps the spectrometer operating at a constant net magnetic field. It compensates for the drift of the superconducting magnet's field and other instabilities. The current in the
			<tt>z0</tt>
			coil is adjusted so that the lock resonance matches a predefined frequency
			<tt>lockfreq</tt>
			. Before activating the lock system you have to find the lock resonance.

	The lock system keeps the spectrometer operating at a constant net magnetic field. It compensates for the drift of the superconducting magnet's field and other instabilities. The current in the <tt>z0</tt> coil is adjusted so that the lock resonance matches a predefined frequency <tt>lockfreq</tt>. Before activating the lock system you ~~have to find the lock resonance.~~		For detailed information on locking you sample see

	~~For detailed information on locking you sample see~~		*[http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199916000b.pdf VNMR 6.1C Getting Started Manual]
	* [http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199916000b.pdf VNMR 6.1C Getting Started Manual]		*[http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199931300b.pdf VNMRJ Liquids NMR Users Guide], section 3.7
	* [http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199931300b.pdf VNMRJ Liquids NMR Users Guide], section 3.7		*BioPack manual
	* BioPack manual

	Note that BioPack installation alters the interface described in the original manuals.		Note that BioPack installation alters the interface described in the original manuals.

	==~~= '''~~Finding Lock Signal Manually~~'''~~ ===		== Finding Lock Signal Manually ==

	First you must start the lock signal display. The channel selector for probe tuning should be at 0.		First you must start the lock signal display. The channel selector for probe tuning should be at 0.
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	Make sure the the lock system is not activated:		Make sure the the lock system is not activated:

	*In VNMR click on the '''LOCK:off''' button in the acquisition window;  <span style="color: green;"> LOCKED </span>should change to <span style="color: red;"> LOCK OFF </span>		*In VNMR click on the '''LOCK:off''' button in the acquisition window;  <span style="color: green;"> LOCKED </span>should change to <span style="color: red;"> LOCK OFF </span>
	*In VNMRJ uncheck the '''Activate Lock''' checkbox		*In VNMRJ uncheck the '''Activate Lock''' checkbox

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	Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.		Also, tuning the lock channel may improve sensitivity. Lock channel tuning is normally available on cryprobes.

	The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.		The field produced by the <tt>z0</tt> coil has some slight z-dependence (mainly linear), which is usually compensated during shimming. On machines with very large field drift this may require using hardware autoshim during long-term experiments.

	==~~= '''~~Finding Lock Signal Automatically~~''' =~~==		== Finding Lock Signal Automatically ==

	In VNMRJ:		In VNMRJ:
	# Go to the '''Setup''' -> '''Lock''' tab
	# Click on the '''Find Lock''' button		#Go to the '''Setup''' -> '''Lock''' tab
			#Click on the '''Find Lock''' button

	This procedure usually takes longer, but may be useful if cannot find the lock resonance manually.		This procedure usually takes longer, but may be useful if cannot find the lock resonance manually.

	Note that you will still need to manually adjust lock power to avoid lock saturation.		Note that you will still need to manually adjust lock power to avoid lock saturation.

	==~~= '''~~Temperature Dependence~~''' =~~==		== Temperature Dependence ==

	The position of the water line in 1H or 2H spectra has a strong dependence on temperature. Since locking matches the deuterium resonance of water to a predefined frequency, <tt>z0</tt> will be different at different temperatures.		The position of the water line in 1H or 2H spectra has a strong dependence on temperature. Since locking matches the deuterium resonance of water to a predefined frequency, <tt>z0</tt> will be different at different temperatures.

	It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).		It also means the total <tt>B0</tt> field will be different even for the same spectrometer and sample locked at different temperatures. Thus, the DSS spectrum should be acquired at the same temperature as the protein sample being referenced. Alternatively, the DSS line position can be tabulated at various temperatures and it temperature dependence determined by a linear regression - this referncing method is employed by Agnus. This referencing method is also unaffected by <tt>lockfreq</tt> reset (see below).

	==~~= '''Solvent Dependence''' =~~==		== ==

	Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.		Deuterons in different solvents resonante at different ppm positions. The lock system, however, would adjust them to the same predefined frequency. Thus, a locked sample in D2O will experience a different B0 field than a locked sample in C6D6.

	To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation		To make sure that the carrier offsets (<tt>tof</tt>, <tt>dof</tt>, <tt>dof2</tt>) stay the same, the lock solvent has to be specfied by setting the <tt>solvent</tt> variable. For example, for protein samples <tt>solvent='d2o'</tt>. For proper names of other lock solvents see the <tt>/vnmr/solventlist</tt> file in your VNMR or VNMRJ installation

	==~~= '''~~Resetting Lock Frequency~~'''~~ ===		== Resetting Lock Frequency ==

	Locking requires setting <tt>z0</tt> so that the deuterium resonance of the solvent (D2O in protein NMR) matches the lock frequency <tt>lockfreq</tt> of the spectrometer. One day you may find that the lock resonance is beyond the operating range of <tt>z0</tt>. In this case it is necessary to reset <tt>lockfreq</tt> to a lower value. This parameter has to be changed on 500MHz, 600MHz and 750MHz instruments in Buffalo about once or twice a year depending on the field drift.		Locking requires setting <tt>z0</tt> so that the deuterium resonance of the solvent (D2O in protein NMR) matches the lock frequency <tt>lockfreq</tt> of the spectrometer. One day you may find that the lock resonance is beyond the operating range of <tt>z0</tt>. In this case it is necessary to reset <tt>lockfreq</tt> to a lower value. This parameter has to be changed on 500MHz, 600MHz and 750MHz instruments in Buffalo about once or twice a year depending on the field drift.
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	'''IMPORTANT!''' Changing <tt>lockfreq</tt> significantly affects referencing with DSS, since you change the B0 field of the spectrometer. '''Always''' record a 1D DSS spectrum with a new <tt>lockfreq</tt>.		'''IMPORTANT!''' Changing <tt>lockfreq</tt> significantly affects referencing with DSS, since you change the B0 field of the spectrometer. '''Always''' record a 1D DSS spectrum with a new <tt>lockfreq</tt>.

	<br>		<br>

	<br> -- Main.AlexEletski - 24 Jan 2007		<br> -- Main.AlexEletski - 24 Jan 2007

Alex: moved NESG:DeuteriumLocking to Deuterium Lock

2009-11-01T22:25:18Z

moved NESG:DeuteriumLocking to Deuterium Lock

← Older revision	Revision as of 22:25, 1 November 2009
(No difference)

Admin at 16:30, 14 October 2009

2009-10-14T16:30:10Z

← Older revision		Revision as of 16:30, 14 October 2009
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	Make sure the the lock system is not activated:		Make sure the the lock system is not activated:

	*In VNMR click on the '''LOCK:off''' button in the acquisition window;  <span style="color: green;"> LOCKED </span>should change to ~~%RED%~~ LOCK OFF~~ %ENDCOLOR%~~		*In VNMR click on the '''LOCK:off''' button in the acquisition window;  <span style="color: green;"> LOCKED </span>should change to <span style="color: red;"> LOCK OFF </span>
	*In VNMRJ uncheck the '''Activate Lock''' checkbox		*In VNMRJ uncheck the '''Activate Lock''' checkbox