Week 7: 2,4-dinitroanisole

I can't believe that we have already passed week seven! Just a few more weeks and I will be back at Lewis & Clark starting my junior year. This week I started running experiments with 2,4-dinitroanisole, or DNAN for short. DNAN is currently being used as an explosive compound in ammunitions production, and so it is of high interest in this project. We expected DNAN to have a slightly faster half life than that of DNT, but slower than TNT, and that turned out to be true, so it was easy to get 3-4 different reaction vials going in one day. I was done with the first set of DNAN trials by wednesday. 

However, I encountered a problem with the faster DNAN trials, in that the data would give me a really nice curve, and a very good line of best fit, except for the last two data points which would drop unexpectedly to zero. 

The graph above illustrates this sudden drop to zero. Additionally, the blue data set was showing me negative concentration values, which doesn't make sense, and consequently, they aren't show on the graph, because you can't take the log of a negative number. 

So, we were somewhat perplexed with the oddness of the DNAN data so we decided to re-run the autosampler vials on the HPLC at a different detection wavelength, 220nm instead of 254, and I re-did one of the really odd DNAN trials, with more frequent sampling intervals in order to see what was going on when the concentrations suddently dropped to zero. All of this extra resulted in not very much information, except that we learned that the HPLC gives fairly similar readings at the two different wavelengths. Now, the negative numbers are also a problem, so to solve those I am running more extensive calibration curves, so that we can get predicted peak areas for known concentrations all the way down to zero, and hopefully that will eliminate the problem with the negative concentration values.