Thursday, June 4, 2009

1st Day of Actual Research

Author: Michael Gerdjikian

(From left to right: TOC Analyzer, UV Spectrophotometer, and Spectrofluorometer)

Today, I began testing some water samples from a desalination plant in California. It was a very interesting day because I had to simultaneously use three of the machines that I had just learned how to use, but never used, the previous day. I tested seven samples from different segments of the plant in order to see how the water quality changes down the line. For example, I tested the raw influent as well as water after microfiltration. I began by running the samples through the TOC analyzer. This was a fairly simple setup as it is all automated. It was a little time consuming as I had to clean out the vials, filter some MilliQ water through the 0.45 micron filter a few times to clean it each time I used a new filter, and then filter the water samples into the vials (while changing the filter several times). After that, running the software was rather straightforward thanks to Don’s handy manual. He watched over me since it was my first time running the machine and everything went smoothly. After I told the software what to do, I started the system and then moved on to the next two machines while it collected all the data for me. Next were the UV Spectrophotometer and the Spectrofluorometer. For these two systems, I prepared one sample at a time for each. This was the best way for me to do it without confusing myself. So if I was testing the raw water, I would prepare only the raw water for each machine at the same time. Again, the painstaking part of these procedures was properly filtering the samples. It took a few tries before I managed to prepare the cuvettes without any fine bubbles within it or marks on the sides of it. Other than that, I learned rather quickly how to use the software. Sergio was sure to help me set up the system before I started testing any samples. It wasn’t until after I had finished with everything in the lab that I started to really understand what it was that I was doing. I took the results straight to Sergio and he talked it over with me. For example, he took the results of the Fluorospectrometer and created EEMs (excitation-emission matrices) from them using MatLab. Using the EEMs, he uses the intensity of the readings to get an idea of how much protein and humic substance is within the water. He then showed me how to subtract intensities from one section of the plant to another to get a visual of what was removed during a certain process, such as a microfiltration membrane. I was excited when the results I gathered corresponded with what we expected to see in the EEMs. Overall, I was very pleased with my work in the lab today and it was a great learning experience for me. I’m actually looking forward to going back to IHE early in the morning to get started on another group of samples.

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