ASITA 2017 post-conference thoughts

The triple helical structure of collagen, the stretchy material that makes up a third of our bone. Complicated, right?

Just got back from the University of Waterloo where the 2017 Advances in Stable Isotope Techniques and Applications (ASITA) workshop was held, and it was eye opening. I learned a few tips, some tricks, and received a whole lot of recommendations that are going to be very useful in our lab over the next few months. This conference was much smaller, had a different crowd and focus than other conferences I've been to. While previous conferences I've attended have really been about scientific theory this conference was really about the nuts and bolts about the methods, which are ultimately essential for advancing theory like you might see at some of the larger gatherings. Of the hundred plus people in attendance, most were lab managers, technicians, people running commercial labs, professors setting up their own labs and seeking expertise in their own institutions, and company sponsors, the manufacturers of instruments used to conduct stable isotope analyses (at times the conference was more like a trade show, with companies advertising the latest and greatest technology).

ASITA, as I learned in the opening presentation, was only formed in the early 90s with the advent of a now ubiquitous setup in many laboratories around the world: the continuous flow isotope ratio mass spectrometer with an elemental analyzer attached. While both those instruments existed in mature forms before they were hooked up to each other, it took around fifty years for people to use them in direct combination. By doing this one could increase the amount of samples to analyze in a single day from maybe ten to over one hundred; a truly revolutionary accomplishment that appeared in just a few years. As people got wind of such a development, ASITA was created to inform the community of stable isotope researchers on how to implement the technology in their own labs. Since then conference has continued to serve the purpose of informing the community of new technological leaps and developments, including new methodologies, incremental progress, and new instruments (such as laser based mass spectroscopy).

Though I was not the only graduate student in attendance we were certainly in the minority. However, it was certainly beneficial to see a different more technical side of the field. Below I'll just summarize some of the things I took notes on or otherwise found interesting:

• Use quarter inch tubing instead of eighth inch on pure oxygen cylinders, lest you experience an explosion due to adiabatic pressure effect leading to flash combustion of micro-fragments in the tube. 
• Though not necessarily useful for my own benefit, many people there were in attendance for a workshop on LIMS, a laboratory information management system. This seems almost necessary for the large commercial labs and government agencies which are handling thousands of samples and clients everyday.
• There is a much larger market for stable isotope analysis outside of academia than I realized. Several of the presentations discussed developments in techniques for identifying performance enhancing drugs in athletes, others in adulteration of foods and in environmental remediation efforts, not to mention forensics. 
• We now have the ability to analyze many of the lighter isotopes using the same instruments in a short amount of time; its possible to analyze a sample nitrogen, carbon, sulfur, oxygen and hydrogen in ten minutes. 
• Ramping the temperature in a GC column allows you to essentially erase the "memory" effects of carbon and sulfur, with sulfur being a particular nasty element that often sticks around long enough to influence the next sample that immediately follows.
• Hydrogen samples can be especially tricky. On many molecules (especially of interest to me, collagen from bones) there exists exchangeable and non-exchangeable hydrogen. We're interested in the non-exchangeable H as that was set in place during an animal's lifetime. After the molecule is exposed after death, the exchangeable H will freely equilibrate with whatever is around it. Therefore, every lab must treat the sample with a carefully controlled atmosphere of known composition so it can be corrected to an international standard. 
• Collagen must also be dealt with fast before analyzing for hydrogen, as the molecule happily absorbs water. Make sure to completely desiccate it before analysis.
• If you're interested in only carbon analysis, check out cavity ring down spectroscopy.
• CSIA (compound specific isotope analysis) via GC-C-IRMS is particularly sensitive to what standard you use (all samples you intend to run must be compared to a substance of known composition so the numbers you receive are comparable between labs) and should be as close to your sample in composition as possible. So if measuring hair, use a hair standard and not some random organic thing, and especially not your reference gas. 
• Splitless injectors for GCMS work seems to be more problematic than the more tradtional split injector. 

If many of these things seem confusing to you, do not worry! I plan to do a series on mass spectroscopy with pictures from our lab this summer. Stay tuned!