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Steven D. Gammon
Mass Spectrometry Theatre: A Model for Big-Screen Instrumental Analysis
Western Washington University Bellingham, WA 98225
John Allison Department of Chemistry, College of New Jersey, Ewing, NJ 08628;
[email protected] Instructors of instrumental analysis courses or advanced or special topics courses often wrestle with the problem of limited teaching instrumentation. This article discusses an approach taken to teach an upper-level course that uses mass spectrometry in forensic chemistry. It is not unreasonable that mass spectrometry (MS) be the subject of an entire undergraduate course, particularly in light of a discussion by Fahey and Tyson on the importance of MS training at the undergraduate level as indicated by employers (1). With 15 students in the class, how can one offer a meaningful lab component to a combined lecture–lab course with one or two gas chromatography–mass spectrometry (GC–MS) instruments? Presented here is an approach that allowed a larger number of students to become familiar with a single instrument that led to a surprising number of new lab teaching options. The Reality The problem is well-known—only so many students can be assigned to work as a group and cluster around a single instrument. However, this problem has evolved over the years because most instruments today are computer controlled, and there are very few if any knobs to turn or interactions with the instrument. In the case of GC–MS, once a vial of sample solution is placed in the autoinjector tray, all interactions are with the computer. Since this is the case, the decision was made to modify the way that the students and instructor interact with each other and the instrument (computer), and the result is called “Mass Spectrometry Theatre”. Mass Spectrometry Theatre: The Hardware The chemistry department currently houses two GC–MS instruments: an Agilent GC–MS (5973 mass-selective detector; 6850 GC; 7683B series autoinjector) and a Varian GC–Ion Trap MS (Saturn 2000 GC/MS/MS with CP-3800 GC; 8200 autoinjector). With a screen and digital projector, one can convert an instrumental lab into a very different classroom. For this course, the laboratory where the GC–MS instruments are housed is sufficiently large that all of the students could bring lab stools into the room. Most commonly, computer cables that connect a computer to its monitor use D-type (15 pin) connectors. A D-type splitter was purchased that allowed the monitor output of the computer to be sent both to the instrument’s monitor and to a digital projector (Epson 811P PowerLite) via a 25 foot cable, creating a large-screen version of the monitor on a large-projection screen. The result is Mass Spectrometry Theatre. Rather than a few students huddling around a computer screen, a large group can now populate the lab where the instrument is housed and work together with a large-screen version of the data system. The entire class can participate in the use of a single instrument, especially in early stages of the course when lab time is devoted to learning how to use the various aspects of the hardware and software (designing GC experiments, MS experiments, data handling, calibration, quantitation, etc.) 1582
Utilizing Mass Spectrometry Theatre Proposed here is one way to effectively use such a modified instrument. For the first part of the course, there were two GC–MS instruments and data systems that each student had to master. A lab is written to walk the students through a process, such as comparing mass spectra obtained to those in a database and database searching. Questions are posed throughout the lab procedure, which are to be discussed in the lab report. Since this is an entire course on mass spectrometry, pairs of students are selected to participate as instrument operators—they actually sit in front of the instrument and use the mouse and keyboard. The operators can be changed every period or a few times during a single lab. There is a reader, who reads aloud the experimental procedure. Most importantly, the instructor is an active participant, the moderator. At appropriate times, the reader pauses to allow the operators to open a window or perform a function. To make the approach effective, in addition to organizing the lab, the instructor should also prepare a script, marking places where questions will be posed to the class to ensure that they understand. In response to a question concerning what should be done next, students walk up to the screen and suggest that a menu be pulled down, or an option selected, or may interact with the screen to ask a question or interpret data. Students are free to discuss options and give the operators their final decision. Everyone can then see how the data system and instrument responds. This fully integrates the instructor into the learning process. The students are not on their own to go through a cookbook lab, the instructor is with them all the way, participating, encouraging, asking and answering questions (something that can not be done when the class is working in multiple small groups). The entire course did not use Mass Spectrometry Theatre; once every student felt comfortable using both instruments, they had experiments to do such as an arson investigation involving accelerant analyses and quantitation of cocaine on paper currency (2). These experiments were designed to have small groups gain experience on both instruments, each doing a part of the work, then passing their results on to the next group for them to complete the experiment. With careful planning, one group of students can be preparing samples or analyzing data while others are taking data, so everyone is busy, even when not using an instrument. Since the lab had two types of mass spectrometers, a quadrupole and an ion trap, each with unique performance characteristics, it was also useful to get the class together to present their results using large-screen projection. It was easy for one group to present their data on the big screen, then switch cables and have the other group, using the other instrument, compare and contrast their experimental results. Students responded well to the challenge, and as questions arose during their presentations, they felt comfortable turning to a spectral database to prove a point or answer a question or to even use the Internet to find an isotope calculator or supplemental material. While
Journal of Chemical Education • Vol. 85 No. 11 November 2008 • www.JCE.DivCHED.org • © Division of Chemical Education
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half of the course did not use Mass Spectrometry Theatre, and other approaches were used to provide students with time to get to know the instruments, Mass Spectrometry Theatre was an effective teaching tool, one that the students embraced. It must be stressed that this is not a process that turns a lab experience into a demonstration. All of the students and the instructor are together in the lab with the instrument. They are all there when the autoinjector starts washing out the syringe, taking up sample, injecting, and starting the run. They experience the moving parts and sounds. They are there when a door on the back of the GC opens and hot air blows out at the end of the experiment (and are usually curious why). As these occur, the instructor can explain the processes to the class. There are several advantages to this approach for laboratory instruction. The first is that it challenges the instructor to not just prepare a lab, but to consider how to create a situation that does not feel contrived, where there is a natural flow of information and a dedication to full and intimate participation. The Committee on Professional Training guidelines from the American Chemical Society (3) emphasize the importance of an effective pedagogy for both the classroom and laboratory, encouraging faculty to teach in “a challenging, engaging, and inclusive manner”. This approach gives the lab instructor the opportunity to do so. A second advantage is that, when students are working in a single group with the instructor, everyone hears the same questions and the same answers. In contrast, when students work in small groups, particularly in round-robin type laboratory courses, the instructor can be spread thin between experiments and students, providing limited support. (Also, when there are more locations than instructors, safety issues arise.) A third advantage is that involved instructors can positively alter class dynamics. If one watches students working in small groups, there is often a dominant student who may take over, as well as the passive student who may be content to sit back and never really learn how to use an instrument. With the instructor presiding and participating, he or she can work to engage both and ensure that everyone is participating at an appropriate level. Also, since students never know who is going to be called on to suggest the next step, they pay attention. This can be a very focused time since, with full faculty involvement, students are less likely to divide their lab time between the experiment and socializing. To maintain full student participation, students should be able to request that a screen or result be printed. This can help them to remember important screens or to collect data that they will discuss in their lab report or during the lab period. Students should be encouraged to request that information be printed for them. A fourth advantage is that full instructor involvement encourages instructors to know the instrument well since they must be prepared for questions that arise. This is, perhaps, one of the uniquely interesting parts of mass spectrometry, because learning how to use the technique will naturally involve a number of questions from the students on instrumentation, data systems, and chemistry. One can often create experimental variations in real time to respond to a question.
mixture that is difficult to separate, one might actually have to do an hour-long experiment. In the early parts of this course, chromatographic conditions were chosen to allow for data to be obtained in several minutes, so the class could begin to discuss data analysis. Instructors may need to plan what to do during data acquisition. In some cases, it is important to watch and comment as the data file evolves. In other cases, it is a good opportunity to begin another discussion. If focus on the subject is not constantly maintained, students will detach from the process and turn to socializing.
Some Points To Consider
Abstract and keywords
A fully participating instructor will quickly learn to appreciate the fact that, for many instrumental methods, data acquisition takes time. To perform a GC–MS analysis of a
Beyond Mass Spectrometry Theatre If one acknowledges that interactions with computercontrolled instrumentation now involves mostly interactions with a computer, then making the computer accessible to a larger number of students by big-screen projection can provide an efficient method for teaching, at least, basic aspects of more complex instrumentation such as MS and NMR. When students are learning how to use an instrument and to do an experiment at the same time, a guided lab inquiry, where the instructor ensures, every step of the way, that everyone understands not just the data system but also the experiment and the chemistry, seems ideal. In my experiences with this approach, I have found that my full participation in the students’ learning process need not take the pressure off of them to figure things out, but takes advantage of my expertise to help them do so. While the approach is surely not for everyone and not appropriate for all possible experiments, it does provide a new challenge through which we can provide instruction. If an instructor uses the approach discussed here, laboratory experiments using instrumentation can be much more than a series of cookbook experiences. Finally, it should be noted that projectors for use with computers and other digital devices continue to become more affordable, and many options are available at stores such as Best Buy. LCD projectors such as Epson’s PowerLite S5, Toshiba’s XGA, and Sharp’s Notevision Educator Series XGA DDR DLP Projector are all available, at the time of writing, for under $900, and are lightweight (
