A Networked NMR Spectrometer: Configuring a Shared Instrument

Sep 1, 2005 - Andrews University (AU), Lake Michigan College (LMC), and Southwestern Michigan College (SMC) established an educational consortium in ...
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A Networked NMR Spectrometer: Configuring a Shared Instrument David Alonso,* G. William Mutch, Peter Wong, and Steven Warren Department of Chemistry and Biochemistry, Andrews University, Berrien Springs, MI 49104; *[email protected] Bal Barot Math/Science/Wellness Department, Lake Michigan College, Benton Harbor, MI 49022 Jan Kosinski and Mark Sinton† Math and Science Department, Southwestern Michigan College, Dowagiac, MI 49047

Spectroscopy is an important part of the overall training of undergraduate chemistry students (1). IR, UV–vis, and NMR instrumentation are critical components of educational instrumental facilities at all colleges and universities. Community colleges are an important group among institutions of higher learning, especially since an estimated 47% of all U.S. undergraduates in public higher education attend community colleges (2). Unfortunately, there are still students without access to modern FT-NMR spectrometers. This is due to the high cost of NMR instruments and their maintenance. Several educational institutions have incorporated modern NMR into their undergraduate programs and have reported the use of shared NMR facilities (3, 4). The sharing normally involves local data acquisition (near the instrument) and processing or data transfer to remote locations for processing. This article describes a model for a shared NMR facility between a private university and two local community colleges. This NMR facility is unique in that data can be easily acquired and processed both locally and remotely without any cost to the community colleges. Students at all three schools use the same protocol to run the instrument, and receive similar training, since the NMR computer hardware and software is identical. NMR software automation mode is used to facilitate NMR usage in lower-level courses. A discussion of the components required for the shared facility, modes of data distribution, and overall effect on the curriculum are presented. NMR Consortium Schools Andrews University (AU), Lake Michigan College (LMC), and Southwestern Michigan College (SMC) are part of an educational consortium established in 1997. Andrews University offers Bachelor of Science degrees in both chemistry and biochemistry. LMC and SMC are community colleges that offer associate degrees in science. Both community colleges are less than 20 minutes driving distance from AU. The consortium received an NSF-ILI grant for the purchase of an FT-NMR spectrometer. The instrument has been used for laboratory courses at AU, LMC, and SMC and for research at AU. The spectrometer has helped the consortium schools improve the quality of chemistry education, exposed students in chemistry courses to the concepts and techniques of modern NMR spectroscopy, and strengthened the collabo-

ration between the chemistry faculties of the three schools. The NMR is housed in the chemistry department at Andrews University. All three schools have the necessary computer hardware and software to remotely access and operate the NMR instrument. There were no initial hardware costs (e.g., computer and software purchases) or NMR maintenance and usage fees for LMC and SMC. NMR data and the NMR instrument are accessible via the Internet (Figure 1). NMR Spectrometer

NMR Hardware A JEOL 400 MHz FT-NMR instrument was installed in the fall of 2001. The NMR is equipped with a variable temperature unit, auto-tuning broadband probe, autosampler, and gradient shim unit. These NMR components are essential for networked instruments to be used in relatively large undergraduate courses. Students can prepare their NMR samples, place them in the autosampler, queue their samples for data acquisition, and then continue working on other aspects of their experiments while they wait for their NMR data. The gradient shim unit and broadband probe are a necessary part of the NMR operation, since they remove the “bottleneck” usually associated with manual shimming. The gradient shim component will automatically shim samples in approximately 2 minutes. The auto-tune unit facilitates the observation of a wide variety of nuclei without having to manually tune the instrument. Finally, the autosampler has greatly increased instrument throughput and has allowed the use of the instrument in the relatively large AU general and organic chemistry courses. An important feature of the AU sampler is the ability to go in the forward (clockwise) and reverse (counterclockwise) directions. This is advantageous

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Current address: Department of Chemistry, Clarke College, Dubuque, IA 52001.

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Figure 1. Consortium network.

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in that proton spectra can be acquired for a series of samples and provided to students during the lab. The sampler can then be set to run in reverse order to acquire carbon NMR data over a longer period of time. This method is superior to running both proton and carbon experiments for each sample in succession. In addition, the auto sampler allows operators to select samples in a non-sequential manner—a feature not available with all NMR auto-samplers.

NMR Computer Hardware and Software The networked JEOL 400 MHz FT-NMR was carefully configured to facilitate remote access and operation. JEOL’s Eclipse NMR computer hardware consists of a Dell workstation and Thales computer running IBM’s AIX version 4. High speed parallel processing is possible since JEOL uses separate host (Dell workstation) and acquisition (Thales computer) processors. NMR experiments are set up on the Dell workstation and then submitted to the acquisition processor. The acquisition processor controls the spectrometer and is part of a system box incorporating the NMR A兾D converter. After completion of an experiment, it automatically transfers the data to the workstation for processing. The AU NMR workstation is currently configured with the Red Hat Linux 9.0 operating system and the NMR software is JEOL’s Delta 4.3. Both the operating system and Delta NMR software are free (5). In addition, a Windows 2000兾XP version of the Delta NMR software is available from the manufacturer and has been installed on several networked lab computers at AU for data processing. The LMC and SMC computers are in the process of being reconfigured as dual boot (Windows XP and Linux) systems. This will permit students to use the workstations for other educational purposes and still allow them to connect to the NMR. One of the major factors in choosing the JEOL NMR was the ability to use Intel processor based PC computers. This lowered the overall cost of the NMR and allowed us to purchase and configure a Dell workstation for each of the consortium schools. These computers are easily and inexpensively upgraded on a regular basis. For example, the AU workstation has recently been upgraded with a new hard-drive, graphic card, and increased memory (RAM). Consortium Network Configuration A considerable quantity of work was devoted to configuring the consortium network (Figure 2). The JEOL NMR system is network ready out of the box. The NMR can be accessed from any location with the proper hardware, software, and high-speed Internet connections. This enhances the ability to share the instrument with other educational institutions. However, speed, security, and network integrity are major concerns at all participating schools. Therefore, the original system was modified to increase network security and enhance performance. An extra Ethernet card was added to the AU workstation. Two Ethernet cards were necessary to protect the less secure Thales Power PC computer and avoid some of the problems associated with computer hacking. In this configuration, the Thales acquisition computer cannot be accessed directly. It can only be accessed through the more secure AU Linux workstation. Ethernet card Eth0 is for highspeed communication between the Thales and Dell computers. Eth1 is the connection to the “rest of the world.” Access www.JCE.DivCHED.org

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to the Linux workstation is limited to encrypted secure shell (SSH) connections from specific locations. The NMR network has been modified several times since the initial NMR installation. This has been necessary owing to internal network changes at each of the consortium schools. These modifications will occur on a regular basis as the schools adjust their networks for fortification. Data Acquisition, Transfer, and Processing

NMR Schedule NMR instrument scheduling follows the AU Chemistry Department schedule of classes. Large laboratory courses have priority during their scheduled meeting times. For example, the AU general chemistry, organic, and physical chemistry labs meet Monday, Tuesday, and Wednesday afternoons respectively. SMC and LMC students typically use the instrument Thursdays. Other users requiring longer acquisition times are scheduled during the evenings or on weekends (Saturday evening and Sunday). Local Data Acquisition and Processing Larger classes run the instrument in Automation Mode. Each student simply inserts his or her sample into an auto sampler slot and enters the necessary information (i.e., filename, solvent, slot number, and type of experiment) to run the sample. There is no need for students to learn NMR commands for experiment submission and data processing. Data are automatically acquired, saved, processed, and printed. As described above, instrument tuning and manual shimming are not required. The data are emailed to students, placed on the AU NMR Web page, and burned onto CDRs for further processing. Data manipulation can take place at any workstation with the Delta NMR software. Students typically transfer data directly from the AU NMR computer or download it from the AU Web site (6). Alternatively, the data are provided to students on CD-R disks. Written processing instructions are available and students use AU lab computers to process and print data. A regular mode for data acquisition is used for our more advanced courses (e.g., physical chemistry). This allows the student NMR user to fully adjust the data acquisition parameters and process the data. In this mode, students also have the option of manually shimming the instrument. It is not surprising that most students (and professors) choose to perform gradient shimming on their samples. Remote Data Acquisition and Processing The major limitation in remote data acquisition is that the samples have to be sent to AU in advance. Alternatively,

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Figure 2. Consortium network configuration.

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sealed NMR tubes for specific experiments are kept at AU and are loaded by AU personnel. The NMR instrument is accessed through SSH. Students log onto their AU NMR workstation account and the Delta NMR application is automatically launched. NMR users can queue jobs and monitor the progress of NMR experiments with Delta’s Master Console and Spectrometer Control windows. Once the students are logged onto the system, there is no difference between local and remote operation, since all three schools use the same computer hardware and software. For security reasons, remote users are locked into the Delta NMR software and cannot access other computer files or applications while logged into the AU NMR computer. Their AU sessions are terminated once they close the Delta NMR application. NMR in the Undergraduate Laboratory The project has been successful in that instrument use by AU, LMC, and SMC students has continued to increase since the initial installation. This is due, in part, to the ease of instrument operation. In its present configuration, very little training time is required to use the NMR. In addition, the project’s principal investigator has continued to serve as the liaison between the community colleges and AU. He is responsible for instrument scheduling, training, data distribution, and network maintenance. This personal touch has led to positive attitudes toward the project and a strong desire to incorporate NMR experiments into various courses in the curricula of the three schools. It is noteworthy to mention that community college students are using the instrument in undergraduate research projects. The primary targets of the consortium were general and organic chemistry courses. However, NMR laboratory experiments were designed so that there is a logical progression in theory and practice as the student advances through the curriculum, ultimately participating in undergraduate research. The organic chemistry courses at the three institutions benefited the most during the two-year project. NMR theory is introduced to sophomore organic chemistry students during the 8th week of class. In a typical organic chemistry class, NMR theory is not introduced until the 14th to 16th week. During an academic year, AU organic chemistry students used NMR in 73% of all of their experiments. Several new experiments were developed and modified and implemented into the curriculum (e.g., Mutarotation of Glucose, CSI experiment, 2D NMR of Heptanones). SMC students used the NMR for a total of six experiments during the 2002–2003 academic year. NMR was also a very important part of undergraduate research at AU. LMC used the NMR in two laboratory experiments and an undergraduate research project that same year. The instrument was used heavily during the academic year and summer to help characterize molecules leading to unsymmetrical phthalocyanines (7). A list of experiments performed during the 2001–2002 and 2002–2003 academic years can be found in the Supplemental Material.W Instrument Maintenance NMR instrument repairs are performed through the manufacturer. Department faculty are responsible other duties such as software and hardware upgrades, network maintenance, and experiment development. A major portion of maintenance duties is the replenishment of magnet cryogens. 1344

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The NMR magnet is filled weekly with liquid nitrogen and with helium every 5–6 months. Conclusion The networked FT-NMR has helped improve chemical education and strengthened collaboration between faculty at Andrews University, Lake Michigan College, and Southwestern Michigan College. The ability to operate an instrument remotely was explored and determined to be a viable option for student training. Careful attention was provided to the selection of NMR components, computer hardware, and software. Use of similar computer hardware and software is highly desirable for a shared NMR facility. For security and performance reasons, the NMR network should be regularly updated to address security and performance concerns. In addition, proper instrument configuration and the ability to run experiments in automation mode has facilitated the use of NMR in larger lower-level courses. Finally, at least one individual should be designated as consortium liaison. This person would assume the responsibility of NMR scheduling, user training, and instrument upgrades. Acknowledgments This work was supported in part by the National Science Foundation (DUE-9750876) and through contributions from AU alumni and friends. W

Supplemental Material

A list of experiments performed during the 2001–2002 and 2002–2003 academic years are available in this issue of JCE Online. Literature Cited 1. Alexander, C. W.; Asleson, G. L.; Doig, M. T.; Heldrich, F. J. J. Chem. Educ. 1999, 76, 1294–1296. 2. The information was obtained from the U.S. Department of Education, Digest of Education Statistics; 2001, p. 210. The document can be downloaded as a PDF file from http:// nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2002130 (accessed Jun 2005). 3. Ball, D. B.; Miller, R. J. Chem. Educ. 2002, 79, 665–666. 4. Benefiel, C.; Newton, R.; Crouch, G. J. J. Chem. Educ. 2003, 80, 1494–1496. Florida State University, NMR Home Page. http://www.chem.fsu.edu/facilities/fa_sl_nmr.asp (accessed Jun 2005). 5. Redhat Home Page. http://www.redhat.com/. JEOL USA, Inc. Home Page. http://www.jeol.com/ (both accessed Jun 2005). 6. Andrew University Home Page. http://www.andrews.edu/chem. (accessed Jun 2005). 7. Undergraduate research poster presentations: Fox, J. F.; Allard M.; Hardesty, W.; Schmid, K.; Shin, E. K.; Carrion, S.; Alonso, D. E.; Lieberman, M. Soluble Copper(II) Phthalocyanines and Unsymmetrical Phthalocyanines for XPS and STM Studies; 225th ACS National Meeting; New Orleans, March 2003. He, W.; Alonso, D. E.; Lieberman, M. Synthesis of Side-BySide Bis(phthalocyanines) by Ring Expansion of Boron Subphthalocyanines; 225th ACS National Meeting; New Orleans, March 2003.

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