The gas chromatograph, until recently, has been a founding member in the exclusive club of scientific instrumentation that lived only in the rarified air of serious scientific laboratories. Other members of the club include the electron microscope, the mass spectrometer, nuclear magnetic resonance spectroscopy, and of course the cyclotron.
Below is a picture of a mass spectrometer at NASA’s Johnson Space Center in Houston. Besides being wildly complex, it takes up the better part of a room, and leaves little to the engineer’s imagination given all the exposed wires, tubes, and components.
For decades, a magic box was the main thing between students and real-time data collection. The magic box went by many names including Universal Lab Interface, MultiPurpose Lab Interface, Serial Box Interface, LabPro, LabQuest, GoLink, LabQuest Mini, and LabQuest2. But in all cases, the excitement over the interfaces provided students with connectivity to instrumentation that in most cases was possible through other means albeit filled with limitations. It has been a while since truly illusive classroom measurements have become possible, and the Mini GC moves the inquiry excitement beyond the interface and into the instrumentation.
I noticed the first hints of a change in the winds of gas chromatography, or GC for short, a couple years after the terror attacks of 9/11. In discussion with a local hazardous materials team I learned that a suitcase-sized GC was onboard their truck. I just had to see it and learn about its operation. A few caveats however. First, the “suitcase” was huge and heavy, but did have a handle and hinges like a suitcase. Second, the suitcase GC cost over $100,000. Third, it was not fast or easy to use, maintain, nor inexpensive to operate. Since that time, GCs have dropped in price and size and increased in speed and number of features, but still a $55,000 13kg suitcase is out of reach of almost every high school. But drop a magnitude and the science teacher’s day just got brighter. What about a $1800 1.3kg GC that can communicate with an iPad? Now we’re talking!
The Vernier Mini GC Plus not only opens up a brave new world of high school/college-level instrumentation, but pushes the envelope of student expectations into uncharted territory; a new intellectual playspace from which there is no turning back.
I belive the Mini GC marks a conceptual change is the dedication to science teaching by a technology company. Many of us are quite happy, overwhelmed perhaps, with all the available probeware, sensors, interfaces, and output options, but the arrival of the Mini GC, whether intentional or not, has raised the bar of imagination for anyone on the delivery or receiving end of high school science.
In a nutshell, the Mini GC Plus is a real gas chromatograph that is smaller and lighter than a six-pack of pop (or soda if you live in that region of the US). The Mini GC does have some limitations in the types of samples it can process, but the mechanics and workflow are true GC.
The Vernier Mini GC Plus connects via USB to a computer running LoggerPro3, or to a LabQuest. If used with an LabQuest 2, the datastream from the Mini GC can be wirelessly collected and analyzed on an iPad running the Graphical Analysis App or viewed in a web browser.
An entire GC run can take as little as five minutes, or much longer if complex compounds are analyzed. The steps are basic since the instrument does the initial work (which is much of the magic of the elite instruments of science). When connected to Vernier software, the GC is autodetected and identified as such, and a window filled with setting choices appears. A couple microliters of a liquid are injected into the GC’s port at the same moment that the data collection run is started. As the volatiles are cooked off in the GC’s oven, a signal of concentration and duration is processed into a spike or spikes on a graph. From that point the statics features of the software can be used for further analysis.
The Mini GC, according to Vernier, “is an instrument for separating, analyzing, and identifying substances contained in a volatile liquid or gaseous sample. The Mini GC Plus can detect and distinguish between families of compounds, including alcohols, aldehydes, ketones, aromatic hydrocarbons, carboxylic acids, esters, ethers, and nitriles.”
A GC operates by heating an extremely small amount of a liquid whereby the individual compounds in the liquid separate out over time yielding both definable characteristics and percentages of the total amount of material analyzed. By cross-referencing the results with knowns, specific compounds and mixtures can be identified.
A webpage at Oregon State University describes this process well as the process being, “similar to a running race where a group of people begin at the starting line, but as the race proceeds, the runners separate based on their speed. The chemicals in the mixture separate based on their volatility. In general, small molecules travel more quickly than larger molecules.”
The workflow for analyzing acetone with the Mini GC, the LabQuest2 and an iPad is presented in the video below recorded at the Vernier exhibitor booth at the 2013 NSTA National Conference in San Antonio, TX.
Now that the Mini GC has raised the high school classroom science teaching bar to what was once an unimaginable level, we can only hope that other members of the exclusive scientific instrumentation club will be available for the cost of less than two football helmets (the Head Impact Telemetry System kind of football helmet, of course.)