Fixing the FeLume

Hi all!

Bill and Jade working away

Our beautiful standards!

Yesterday we had a lot of samples that came out of the solar simulator that we analysed for carbon monoxide, hydrogen peroxide, and photochemical fading (basically, the last one is looking at how much the molecules in the solution absorb light).  When we started up our instruments to prepare to run the samples, the instrument we use to measure hydrogen peroxide (the FeLume) was not working properly.  So Jade and Bill set out to fix the problem!  They changed tubing, check connections, changed reagents, and checked many other

things to no avail.  Jade had a few of the main components of the FeLume that she brought with her just in case we needed them, and she decided that it was time to take the FeLume apart and switch them out!  So she and Bill replaced what's called the flow cell, where our chemiluminescent reaction takes place and the detector measures how much light is produced.  That seemed to help, but when they ran solution through the flow cell they found a leak!  Jade was so scared that the flow cell might be broken, but luckily it was a minor problem that we fixed with relative ease.  To make sure everything was working properly, we ran our standards.  Standard solutions are ones that we make in seawater, and add in known amounts of hydrogen peroxide.  That way, we can relate the signal the FeLume gives us to the concentration of hydrogen peroxide present in the solution, and can calculate the amount of hydrogen peroxide in our samples that we irradiate with the solar simulator (or solar similar-ator as I think Bill called it in his previous post).  As you can see in the picture, our standards came out beautifully!  You can clearly see how the the increasing concentrations of hydrogen peroxide that we added effects the FeLume signal (the first three peaks are just the seawater with no hydrogen peroxide added, and we increase the concentration up to 100 nanomolar).  We had a lot of samples to run once the FeLume was fixed, but at least we were able to run them!!  And all the samples that we've run today have looked GREAT!  Let's hope that tomorrow is just as good.

Best,
Meg

P.S.  Keep tuned for a blog post about the chemiluminescent reaction that we use to measure how much hydrogen peroxide is in our solution.  It's pretty cool!