{"title":"固体中半整数四极核的加速高分辨率核磁共振:SPAM-MQMAS和SPAM-STMAS","authors":"Akiko Sasaki , Yu Tsutsumi , Jean-Paul Amoureux","doi":"10.1016/j.ssnmr.2020.101668","DOIUrl":null,"url":null,"abstract":"<div><p><span><span>In solid-state NMR, multiple-quantum MAS (MQMAS) and satellite-transition MAS (STMAS) experiments are well-established techniques to obtain high-resolution spectra of half-integer quadrupolar nuclei. In 2004 and 2005, a soft-pulse-added-mixing (SPAM) concept was introduced by Gan and Amoureux to enhance the S/N ratio of </span>MQMAS and STMAS experiments. Despite their robustness and simplicity, SPAM approaches have not yet been widely applied. Here, we further exploit SPAM concepts for sensitivity enhancement upon acquisition of two-dimensional MQMAS and STMAS spectra and also establish a general procedure upon implementation of SPAM-MQMAS and SPAM-STMAS NMR. Its effectiveness and ease in experimental setup are demonstrated using simulations and experiments performed on I = 3/2 (</span><sup>23</sup>Na, <sup>87</sup>Rb), 5/2 (<sup>27</sup>Al, <sup>85</sup>Rb) and 9/2 (<sup>93</sup>Nb) nuclei with a variety of quadrupolar coupling constants (C<sub>Q</sub>). Compared to the conventional z-filter methods, sensitivity enhancements in between 2 and 4 are achievable with SPAM. We recommend to use SPAM with a ratio of 4:1 for the number of echoes and antiechoes to safely maximize the sensitivity and resolution simultaneously. In addition, a comparison of the experimental approaches is made in the context of SPAM-MQMAS and SPAM-STMAS NMR with respect to repetition delay and spinning frequency, aiming to discuss the precautions upon making a judicious choice of high-resolution NMR methods of half-integer quadrupolar nuclei.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ssnmr.2020.101668","citationCount":"3","resultStr":"{\"title\":\"Accelerating high-resolution NMR of half-integer quadrupolar nuclei in solids: SPAM-MQMAS and SPAM-STMAS\",\"authors\":\"Akiko Sasaki , Yu Tsutsumi , Jean-Paul Amoureux\",\"doi\":\"10.1016/j.ssnmr.2020.101668\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p><span><span>In solid-state NMR, multiple-quantum MAS (MQMAS) and satellite-transition MAS (STMAS) experiments are well-established techniques to obtain high-resolution spectra of half-integer quadrupolar nuclei. In 2004 and 2005, a soft-pulse-added-mixing (SPAM) concept was introduced by Gan and Amoureux to enhance the S/N ratio of </span>MQMAS and STMAS experiments. Despite their robustness and simplicity, SPAM approaches have not yet been widely applied. Here, we further exploit SPAM concepts for sensitivity enhancement upon acquisition of two-dimensional MQMAS and STMAS spectra and also establish a general procedure upon implementation of SPAM-MQMAS and SPAM-STMAS NMR. Its effectiveness and ease in experimental setup are demonstrated using simulations and experiments performed on I = 3/2 (</span><sup>23</sup>Na, <sup>87</sup>Rb), 5/2 (<sup>27</sup>Al, <sup>85</sup>Rb) and 9/2 (<sup>93</sup>Nb) nuclei with a variety of quadrupolar coupling constants (C<sub>Q</sub>). Compared to the conventional z-filter methods, sensitivity enhancements in between 2 and 4 are achievable with SPAM. We recommend to use SPAM with a ratio of 4:1 for the number of echoes and antiechoes to safely maximize the sensitivity and resolution simultaneously. In addition, a comparison of the experimental approaches is made in the context of SPAM-MQMAS and SPAM-STMAS NMR with respect to repetition delay and spinning frequency, aiming to discuss the precautions upon making a judicious choice of high-resolution NMR methods of half-integer quadrupolar nuclei.</p></div>\",\"PeriodicalId\":21937,\"journal\":{\"name\":\"Solid state nuclear magnetic resonance\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.8000,\"publicationDate\":\"2020-08-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/j.ssnmr.2020.101668\",\"citationCount\":\"3\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Solid state nuclear magnetic resonance\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0926204020300308\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Solid state nuclear magnetic resonance","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0926204020300308","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Accelerating high-resolution NMR of half-integer quadrupolar nuclei in solids: SPAM-MQMAS and SPAM-STMAS
In solid-state NMR, multiple-quantum MAS (MQMAS) and satellite-transition MAS (STMAS) experiments are well-established techniques to obtain high-resolution spectra of half-integer quadrupolar nuclei. In 2004 and 2005, a soft-pulse-added-mixing (SPAM) concept was introduced by Gan and Amoureux to enhance the S/N ratio of MQMAS and STMAS experiments. Despite their robustness and simplicity, SPAM approaches have not yet been widely applied. Here, we further exploit SPAM concepts for sensitivity enhancement upon acquisition of two-dimensional MQMAS and STMAS spectra and also establish a general procedure upon implementation of SPAM-MQMAS and SPAM-STMAS NMR. Its effectiveness and ease in experimental setup are demonstrated using simulations and experiments performed on I = 3/2 (23Na, 87Rb), 5/2 (27Al, 85Rb) and 9/2 (93Nb) nuclei with a variety of quadrupolar coupling constants (CQ). Compared to the conventional z-filter methods, sensitivity enhancements in between 2 and 4 are achievable with SPAM. We recommend to use SPAM with a ratio of 4:1 for the number of echoes and antiechoes to safely maximize the sensitivity and resolution simultaneously. In addition, a comparison of the experimental approaches is made in the context of SPAM-MQMAS and SPAM-STMAS NMR with respect to repetition delay and spinning frequency, aiming to discuss the precautions upon making a judicious choice of high-resolution NMR methods of half-integer quadrupolar nuclei.
期刊介绍:
The journal Solid State Nuclear Magnetic Resonance publishes original manuscripts of high scientific quality dealing with all experimental and theoretical aspects of solid state NMR. This includes advances in instrumentation, development of new experimental techniques and methodology, new theoretical insights, new data processing and simulation methods, and original applications of established or novel methods to scientific problems.