Rube Goldberg Lives Again!

As a part of my Master’s thesis, I was tasked with measuring the rate of oxygen exchange between VO₂⁺ and H₂O¹⁸ labeled water. Unfortunately, the VO₂⁺ exchange rate is insanely fast, much better suited to NMR based studies which were beyond the capabilities of our group. I managed to slow the exchange reaction by complexing the VO₂⁺ with oxalate, but with a resulting half-life on the order of 2 seconds, it was still a bitch of an experiment to do. Basically the procedure involved injecting a known amount of O¹⁸ enriched water into about 1 ml of VO₂(C₂O₄)₂^3- solution followed by the injection of a solution of Co(en)₃Cl₃ to precipitate the vanadium complex and stop the O exchange. Subsequent isotopic analysis of the Co(en)₃VO₂(C₂O₄)₂ gave me the exchange rate. Due to the rapid reaction rate, the time between the 2 injections ranged between 0.5 to 8 seconds and since both my hands were busy holding the injectors (a plastic syringe and a 100uL pipettor), I used a foot activated electronic timer to measure the time interval. Although my results looked pretty good, my advisor informed me that I would need to find a way to automate the timer or else no one would believe my results. I’m not sure that was really true, but when your advisor suggests something…. Since our group didn’t have a lot of money to spend, I ended up scavenging around for old switches and devices which I could take apart and attach to my injectors. After much trial and error, I concocted a device which actually worked (much to my surprise), but which was also rather frightening to behold. (I wish I still had a picture of it) The injectors were held locked into place on a ring-stand assembly with electrical contacts attached in bizarre ways so that the timer would be started and stopped by the acts of injection. Even though it appeared ready to fall apart, it worked surprisingly well, allowing me to routinely perform 0.5 second runs with reproducible results. The first time my advisor saw it, he simply smiled and said: “Nice job, Rube,” referring to Rube Goldberg, the cartoonist known for depicting ridiculously complex devices that perform simple tasks in indirect, convoluted ways. The building of that injector system is still one of my best memories from graduate school. In memory of that system, here is a link to an amusing advertisement based on Rube’s ideas.