Quite some time has passed since the last update. During that time I continued doing the same procedure for the rest of the samples that I had left.

We did encounter a problem with the FTIR. When one would take the spectrum of a sample with an aperture of 25x25 µm, the peaks on the graph would come out very saturated. I did not ask why this was happening but the solution to the saturation problem was duct tape!

My assumption is since the duct tape is sealing the tube that connects both segments of the FTIR, this stops the labs atmosphere from getting into it. This is important because the inside of the FTIR has to be in specific conditions in order to take a clear spectrum of the sample without the interference of other particles.

I have also begun interpreting the spectrums data by computing the samples average thickness and peak heights into an excel spreadsheet that would then calculate the amount of water and other concentrations within the species. Once I am done computing these values for every sample, they can then be plotted to see if there is any trend.

Week 3/13-3/17/17

As promised from the previous post, I will explain how to read data from the spectrum the FTIR gives.

This is the spectrum of a sample and what we want to get from this is the height and position of the peak. The first peak (going from left to right) indicates that oxygen is present. The second peak, the one that splits into two at the top, indicates CO2. These two are what we want to measure. Doing this is very simple since the program has a tool that can be used to measure it.

This tool is called Baseline correct. To my understanding, it allows us to create a line under the peaks which then makes a function of whatever lies above that line. Afterwards we can choose any point above the line and it would give the height.

 At first glance will look like this:

Before the line can be drawn, the tool has to be on specific settings. First, the function type needs to be changed to “spline” and “auto-y” needs to checked off to make placing the line easier. After that is done, making the line is easy by clicking anywhere near the peak that is being measured but not on it. Doing so will result with something like this:

After that, hit replace giving a zoomed in version of just the peak. From here, we select another tool that allows to measure the height of the peak. A horizontal line acts as zero and a vertical line that gives the height on the given point from the horizontal. Both of these lines can be moved freely throughout the spectrum.

The bottom left corner of the program will give us the height and position. In this case the height: 1.252 and position(x value): 3536

Afterward, we do this for the CO2 peak. The same process except we get two heights.

This is the data collecting process I go through and it is not that difficult (so far). I find it a lot more difficult to get the spectrum itself versus reading it. Regardless, there will be problems still to overcome.

Week 3/6-3/10/17

In this week, I was finally able to make a sense out of the data I am collecting. Before I give a quick explanation you should know my objective, which is to find the concentration of water in volcanic glass samples from the ocean floor. The FTIR does this by giving the concentration of carbon dioxide and oxygen.

Now, it will be difficult to explain without images, since I forget to take pictures, but I will try to give an abridged form. So, this “data” I’m getting from the FTIR comes in the form of a graph and on the graph there are at least three peaks. The first one indicates oxygen and the other two carbon dioxide (which are very close together). I’ll be honest, I don’t know or understand how you identify those peaks to be concentrations of O2 or CO2 but I was told that and I’ll just assume it’s something very complicated to explain.

Okay so with these graphs I can then measure the peaks height and absorbance (or was it concentration?). From here, I take this data along with several other data points and the average thickness of the same sample and plug it into a prepared excel sheet that my mentor created. This excel spreadsheet has several parts to it where you just plug in the values accordingly and your end result is an approximation of water concentration in the sample.

This about sums what I learned in a very not-so-detailed fashion.

I was assigned my own set of samples to work on. If I recall, they originate from or near the East African rift.

As I work along with these samples, I will give in better detail the process I undergo with pictures!

Week of 2/17-3/3/17

This week I was trained to use the FTIR. Before I begin to use the machine to take data from the sample; I first, need to make sure that everything is in the right conditions. To prepare for testing, I need to turn on the air valve and hook it to a device that reads the moisture in the air that is being blown through. The chamber of the FTIR needs to have zero moisture since the moisture in the air can interfere with the results. Once the dry air is going through the chamber, I can then turn on the FTIR and pour liquid nitrogen into the second chamber, the one with the microscope, to cool it down.

Once the setup is complete, I check if the FTIR is cold enough by using a computer program. From there I am/was able to begin taking practice sample data to get accustomed to the FTIR computer program and its different functionalities.

*The FTIR. On the left is the first “chamber” and on the right the second “chamber” I talked about. The green thermos on the right is used to pour liquid nitrogen into the second chamber.

*The FTIR. On the left is the first “chamber” and on the right the second “chamber” I talked about. The green thermos on the right is used to pour liquid nitrogen into the second chamber.

In the week of 2/20-2/24, I met with Maryjo and she showed me the equipment I will be working with and its insides. I forget the technical term/name of the instrument (FTIR?) but it is basically a microscope that uses a laser to measure the sample. It was interesting to see how the laser would be in a separate chamber and would bounce off mirrors, split, and rejoin only to be shot into the next section which has the microscope. From that, the computer on the microscope will give a value/measurement for us to use.

From my understanding and Maryjo’s explanation, we will apply Beer’s law in conjunction with the data we get from the microscope. Using that data, we would then apply it to an equation to get the concentration of “x” that we are looking at. For now I have an understanding of what I will be doing, but to explain in better detail I would need to do some hands on work to have a clear idea. By the end of next week, I should have training on the equipment complete and have done some practice samples on my own.