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4    ADJUSTMENT OF MEASUREMENT CONDITIONS AND PROCESSING CONDITIONS 

 

4.5  SETTING SAMPLING POINT (X_POINTS) 

The parameter

 x_points

 specifies the number of sampling points to acquire FID data.  

For a solid-state NMR measurement, this parameter is used to adjust the decoupling time.  
Since decoupling time is the same as acquisition time, it is expressed as 

x_acq_time

. 

High-power RF will be input to the probe during 

x_acq_time

. 

 

In order to reduce the load of the probe, it is necessary to shorten 

x_acq_time

. However, 

if 

x_acq_time

 is too short, the FID signal will not be acquired. Ideally it is best that 

x_acq_time

 is as short as possible while still acquiring the entire FID signal. A good 

example and a bad example are shown in the following figure. As estimates, 

x_acq_time

 

is about 20 ms in polymers and about 40 to 100 ms in crystals. 

 

Good example

Undesirable example: 

x_acq_time

is too long.

Bad example: 

x_acq_time

 is too shor t

 

Fig. 4.4 Good and bad examples of acquisition time 

NMECAXS_V50-SLD-2  

4-5

 

Содержание JNM-ECA Series

Страница 1: ...USER S MANUAL For the proper use of the instrument be sure to read this instruction manual Even after you read it please keep the manual on hand so that you can consult it whenever necessary INMECAXS...

Страница 2: ...standard composition This manual explains about cautions measurement conditions processing conditions multi nuclear measurement relaxation time measurement and pulse sequence used in the solid experi...

Страница 3: ...ed or transported without the supervision of the personnel authorized by JEOL JEOL will not be held responsible for any loss damage accident or problem with the instrument Operating the improperly ins...

Страница 4: ...ghts to Licensed Software All rights related to the Licensed Software including copyrights belong to JEOL Article 6 Warranty 1 JEOL does not guarantee proper performance of the Licensed Software if it...

Страница 5: ...iances and machines often contain materials which if handled or disposed of incorrectly are potentially hazardous to human health and to the environment They are however essential for the correct func...

Страница 6: ...it Selecting a menu item from a pulldown menu is denoted by linking the menu and the item with a dash For example File Exit means selecting Exit from the File menu Ctrl Keys on the keyboard are denote...

Страница 7: ...3 SETTING OF IRRADIATION FREQUENCY 3 4 3 4 SETTING PULSE WIDTH 3 5 3 5 ADJUSTMENT OF RESOLUTION 3 7 3 6 REFERENCE SETTING 3 8 3 6 1 External Reference Setting 3 8 3 6 2 Reference Setting by Using Z0...

Страница 8: ...SURING 1 H 19 F 5 2 5 4 METHOD OF MEASURING NUCLEUS OF SPIN 1 5 3 5 5 METHOD OF MEASURING NUCLEUS OF HALF INTEGER SPIN 5 3 6 MEASUREMENT OF RELAXATION TIME 6 1 OUTLINE OF RELAXATION TIME MEASUREMENT 6...

Страница 9: ...hese locations with your hands or anything else Beware of electric shock Beware of laser Beware of super low temp Beware of getting caught Beware of biohazard Do not disassemble Beware of heat Example...

Страница 10: ...of the instruments and related attachments purchased from JEOL Consult your JEOL service office WARNING When you use nitrogen gas provide ventilation sufficient for the rate of gas usage When ventila...

Страница 11: ...o flow bearing gas If you do not flow the bearing gas the heater produces anomalous heating then a fire might occur inside the probe When you set the measurement temperature to 150 or more be sure to...

Страница 12: ...1 OUTLINE OF SOLID STATE NMR MEASUREMENT 1 1 SOLID STATE NMR SYSTEM 1 1 1 2 DIFFERENCE BETWEEN SOLID STATE NMR AND SOLUTION NMR 1 2 NMECAXS_V50 SLD 2...

Страница 13: ...ment un der variable temperatures VT are also possible with this system If the Status cable is connected to the Status connector of the solid probe the program and the spectrometer will enter the soli...

Страница 14: ...vent the special features of the solid state will be lost On the other hand in solid state NMR the sample can be observed as it is However analysis of the spectrum becomes difficult in solid state NMR...

Страница 15: ...MAGIC ANGLE SPINNING 2 2 2 3 HIGH POWER DECOUPLING 2 3 2 3 1 CW Continuous Wave Decoupling 2 3 2 3 2 TPPM Two Pulse Phase Modulation Decoupling 2 3 2 4 SINGLE PULSE MEASUREMENT 2 4 2 5 CROSS POLARIZA...

Страница 16: ...uniformly and aver aged If the molecule is carrying out rotational Brownian motion the anisotropic terms disappear and only the isotropic terms remain Spectroscopy of solution NMR is constructed under...

Страница 17: ...B0 Fig 2 1 Magic Angle Sample Spinning MAS can eliminate all the anisotropic interactions expressed as second rank tensors HD HCSA HQ However when the MAS frequency is smaller than the interaction the...

Страница 18: ...gnal appears as a cycling sideband In a pulse sequence having a long cycle the decoupling effect is decreased by inter ference with MAS Moreover CW decoupling has been a reliable decoupling technique...

Страница 19: ...NGLE PULSE MEASUREMENT One of the fundamental measuring methods of a solid state NMR measurement is a sin gle pulse measurement When you carry out a single pulse measurement you use MAS Usually althou...

Страница 20: ...rengths for I and S nucleus as B1 I and B1 S and ratio of I and S nucleus as I and S respectively the Hartmann Hahn conditions can be expressed with the following formula I B1 I S B1 S Be aware of the...

Страница 21: ...zation condition under high speed MAS depends on the spin ning speed The Hartmann Hahn condition taking into account the spinning speed un der high speed MAS is as follows I B1 I S B1 S n r n 1 2 Thus...

Страница 22: ...OLUTION 3 7 3 6 REFERENCE SETTING 3 8 3 6 1 External Reference Setting 3 8 3 6 2 Reference Setting by Using Z0 Shim 3 9 3 7 ADJUSTMENT OF CROSS POLARIZATION CONDITIONS 3 10 3 7 1 Adjustment of Cross P...

Страница 23: ...xide would block a pipe causing failure The NMR detection coil would also oxi dize and performance of the probe would deteriorate Nitrogen gas When you use nitrogen gas check that the specification of...

Страница 24: ...J Magn Reson A 116 215 220 1995 T Takahashi H Kawashima H Sugisawa and T Baba Sold State Nuc Magn Reson 15 2 119 1999 For the calibration of the temperature use a lead nitrate sample The amount of sh...

Страница 25: ...opriate for the bromine 79 observation 4 Load the pulse sequence mas_adjust_KBr jxp to the Experiment Tool 5 Click the Submit button The pulses occur and the measurement starts 6 Adjust the phase by t...

Страница 26: ...Insert the standard sample adamantane 2 Perform spinning 3 Load the pulse sequence single_pulse_solid jxp into the Experiment Tool 4 recvr_gain is set 5 Click the Submit button The pulses occur and t...

Страница 27: ...insert the adamantane standard sample 2 Perform spinning 3 Set single_pulse_solid jxp for the 1 H measurement and sin gle_pulse_dec_solid jxp for the 13 C measurement in the Experiment Tool 4 recvr_g...

Страница 28: ...spectrum after the Linearize processing the pulse width where the signal in tensity is nearest to 0 zero is the 360 pulse width Furthermore for longer pulse widths the peaks should be positive Fig 3 4...

Страница 29: ...sing Tools panel does not appear click the Phasing button on the far right side 7 Expand near the peak and check the half height width When spectrum data points are lacking select the process list tha...

Страница 30: ...rnal reference substance and carry out the reference setting Refer to the user s manual Data processing for details for setting the refer ence 2 In the Delta Console window select Tools Geometry Tools...

Страница 31: ...e measurement time are recorded the average amount of drift can be calculated from the values Z0 drift can be corrected automatically by setting this amount of drift to the drift canceler that is expl...

Страница 32: ...adamantane 2 Perform spinning at 5 kHz 3 Load the pulse sequence cpmas jxp into Experiment Tool 4 Set scans to a multiple of 2 5 Set obs_shape_cp to constant_cp 6 Set irr_amp_cp value of Proton 7 Set...

Страница 33: ...compensate for such im perfection the modulation is applied to the output power of the observation channel dur ing spin lock thereby increasing sensitivity 1 H 13 C Decoupling Contact Time 1 H 13 C am...

Страница 34: ..._amp_cp 3 7 4 Selecting a Method for Cross Polarization There are several methods for the cross polarization in the CPMAS measurement You can change the method by choosing combinations in irr_shape_cp...

Страница 35: ...equipment When the data acquisition time is longer you need to lower the value of irr_amp_dec and measure 3 8 2 Setting of TPPM Decoupling Conditions In the decoupling of TPPM Two Pulse Phase Modulati...

Страница 36: ...th_xix that gives the strongest signal intensity of the C car bon The best condition of the XiX depends on the spinning speed When you change the spinning speed in a measurement adjust the measurement...

Страница 37: ...ane obtain the values of irr_width_cm and irr_phs_tppm that give the strongest signal intensity 3 8 6 Setting of SWf TPPM Decoupling Conditions To perform SWf TPPM SWept Frequency Two Pulse Phase Modu...

Страница 38: ...or a measurement more useful data can be obtained by using the optimum values for each sample 4 1 SETTING PULSE WIDTH IN SINGLE PULSE MEASUREMENT 4 1 4 2 SETTING WAITING TIME IN SINGLE PULSE MEASUREME...

Страница 39: ...teraction the 90 pulse width depends on the strength of the interaction When the nuclear quadrupole interaction is small the 90 pulse width is almost the same width as that in the solution However as...

Страница 40: ...leus is very long set a small flip angle obs_angle_prep and measure it However when performing a quantitative measurement setup the relaxation_delay to 5 or more times the longest T1 among the observe...

Страница 41: ...n in the following figure The maxi mum signal intensity occurs during 1 to 2 ms for typical organic compounds There are also samples that require longer contact time among samples with rapid molecular...

Страница 42: ...values as estimations Approximately 2 to 5 s when the sample includes the methyl group as one of its main components Approximately 5 to 10 s for a polymer that contains almost no methyl groups Approx...

Страница 43: ...obe during x_acq_time In order to reduce the load of the probe it is necessary to shorten x_acq_time However if x_acq_time is too short the FID signal will not be acquired Ideally it is best that x_ac...

Страница 44: ...small 1 Recall data 2 Set the value of Zerofill as follows a Select PreTransform Zerofill b Set Times of Zerofill in the process list to two or more Forward linear prediction complements the data for...

Страница 45: ...sed in measurements with wide observation ranges such as multinuclear measurements Substitution of data point 1 Recall the data 2 Set up Blip as follows a Select PreTransform FID Prediction Blip b Set...

Страница 46: ...ULTINUCLEAR MEASUREMENT 5 1 5 2 METHOD OF MEASURING RARE SPIN NUCLEUS OF SPIN 1 2 5 2 5 3 METHOD OF MEASURING 1 H 19 F 5 2 5 4 METHOD OF MEASURING NUCLEUS OF SPIN 1 5 3 5 5 METHOD OF MEASURING NUCLEUS...

Страница 47: ...gnetic ratio means a strong magnetic dipole interaction and a high natural abundance means that the observation spins have complex interactions with each other Therefore it is difficult to measure hig...

Страница 48: ...method Mainly used sequence single_pulse_solid jxp single_pulse_dec_solid jxp cpmas jxp 5 3 METHOD OF MEASURING 1 H 19 F In order to measure 1 H and 19 F it is necessary to suppress the broadening of...

Страница 49: ...aration capability of the peaks increases By using the NMR instrument with a high magnetic field even for a nucleus like 27 Al the peak separation becomes possible to a certain extent Although availab...

Страница 50: ...6 1 6 2 RELAXATION TIME MEASUREMENT BY DIRECT MEASUREMENT 6 2 6 3 RELAXATION TIME MEASUREMENT OF 13 C BY TORCHIA METHOD 6 4 6 4 MEASUREMENT OF T1 T1 IN THE ROTATING FRAME 6 5 6 5 RELAXATION TIME MEASU...

Страница 51: ...olecular motion of the specific site Also for optimizing the measurement parameters or performing the quantitative measurement it is necessary to measure the exact relaxation time of each peak in adva...

Страница 52: ...used inversion_recovery jxp inversion_recovery_dec jxp Refer to the user s manual Application for the measurement and processing of the inversion recovery method T1 calculation method for T1 data obta...

Страница 53: ...is the same as that for the inversion recovery method use the following approximation formulas Weighted Linear Sat Recovery The weighted linear least squares method The weight is reduced for the measu...

Страница 54: ...e number of two 3 Set the array parameters for interval based on the estimated T1 value Setup the array variable for performing the Torchia method in decreasing order The arrow buttons enable you to s...

Страница 55: ...ay parameters for obs_width_lock based on the estimated T1 value Setup the array variable for performing the Torchia method in decreasing order The arrow buttons enable you to switch between increasin...

Страница 56: ...recovery method When the relaxation time of 1 H is measured by using the inversion recovery method with CPMAS the following pulse sequence is used inversion_recovery_1h_cpmas jxp In the usual inversi...

Страница 57: ...od the DAS Dynamic Angle Spinning method and the MQ Multiple Quantum MAS method are known as measuring methods that re move quadrupolar interactions However since the DOR method and the DAS method nee...

Страница 58: ...aving a spin 1 2 information about how many sites exist can only be obtained by the MAS spectrum For nuclei having a half integer spin the site analysis is difficult when you only use the MAS spectrum...

Страница 59: ...c High magnetic field required High RF power is indispensable in the MQMAS method in order to cause the magnetiza tion transfer with multiple quantum coherence If the power weakens the signal intensit...

Страница 60: ...e of the 3QMAS method consists of two simple pulses The spin system is excited to 3 quantum by the first pulse and evolved during time t1 by us ing phase cycling in which only 3 quantum coherence rema...

Страница 61: ...remains Then 3 quantum coherence is converted to zero quantum coherence and signals other than the Z axis are eliminated af ter the second pulse Finally the signal of the Z axis is excited to single q...

Страница 62: ...2 Perform spinning 3 Load the pulse sequence single_pulse_solid jxp to the Experiment Tool 4 Set obs_angle_prep to 90 deg The 90 pulse width is not equal to 1 4 of the 360 pulse width because of the i...

Страница 63: ...essing for the procedure for processing the data obtained by the array measurement After data processing the result is displayed by Linearize 9 Seek the obs_amp_pulse having the strongest signal inten...

Страница 64: ...easurement ends the nD Processor window opens automatically 9 Perform data processing Refer to the user s manual Data processing for the procedure for processing the data obtained by the array measure...

Страница 65: ...mqmas_3Q_z jxp 3 Set up y_sweep Perform the scaling processing Sect 7 6 2 for the t1 axis of the MQMAS spectrum Therefore it is necessary to set a wider y_sweep width than the line width of the 1D spe...

Страница 66: ...ction i Scaling processing Sect 7 6 2 Processing procedure This section explains the data processing after the measurement is completed and the data is transferred from the spectrometer When the measu...

Страница 67: ...ress the Cut button 4 Click the Open Process List button to load the process list of MQMAS The process list to load is different for every nuclear spin number of the measure ment nucleus and measuring...

Страница 68: ...orrection that was cut in step 3 is added 6 Perform phase correction of the F1 axis Click the 2D Phase button and perform phase correction of F1 axis in the open window 7 Display the two dimensional s...

Страница 69: ...the Fourier transform is carried out by the usual method for such two dimensional FID data it will become a tilted two dimensional spectrum Therefore we must change it into an ordinary spectrum by pe...

Страница 70: ...d order quad rupoler coupling the multiple quantum chemical shielding shifts the peak position in the isotropic axis of the MQMAS spectrum Therefore it is necessary to correct the scaling of the chemi...

Страница 71: ...CP 2 5 CW Continuous Wave Decoupling 2 3 3 13 TPPM 3 13 TPPM Two Pulse Phase Modulation Decoupling 2 3 DAS Dynamic Angle Spinning 5 3 7 1 DOR Double Rotation 5 3 7 1 VACP Conditions 3 11 MAGIC ANGLE...

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