About Me: Hello, my name is Demetrios Kennedy, and I am enrolled at WPI. I major in chemistry, and I am also a member of the Teacher Preparation Program at WPI. From January 2nd to May 3rd, I spent my time student teaching high school students at Doherty Memorial High School. This is my first year participating in the RET program and I hope to learn a lot during my time here.

 

About the Lab: For this research project, the goal is to quantify the amount of PFAS (per- and polyfluoroalkyl) in waste feedstocks and products. While PFAS research started in the late 1930s, PFAS wasn’t used that often in products until the 1950s. However, further research done from the 1970s and onwards detected PFAS in the blood of exposed workers, and research in the 1990s detected the chemical in the blood of the general population. The amount of PFAS concentration in human blood has decreased since 2000, but exposure to these chemicals can lead to adverse health effects. During the last couple of years, EPA has released methods to detect PFAS in a variety of substances. On February 15, 2024, EPA released a method allowing detection of PFAS in the walls of containers made from high-density polyethylene (HDPE). In December 2022, 12 PFAS chemicals were removed from a list of chemicals that could be used in nonfood pesticide products. These findings are helpful, but with how recent these discoveries are, this makes discovering and quantifying PFAS important. 

This research project will be done through methods such as liquid chromatography, which will allow for the separation of prepared solutions. This will let us analyze the amount of PFAS inside of a given sample of waste.

Quantification of Forever Chemicals (PFAS) in Waste Feedstocks and Products

 

Weekly Updates

Week 1

Week 1 was spent understanding the equipment that I will be using for this research. The machine is the Agilent 6546 LC/Q-TOF and the purpose of the machine is to take a mixture, break up the mixture into its components, and then analyze a component from the original mixture. Throughout the week, I have been working through the training of this machine so that I will be able to use it during the following weeks. On top of learning about the machine and the method I will be using to prepare the samples to be analyzed, I got to meet my faculty mentor Andrew Teixeira and my In-Service partner Jay Turner.Here is the picture of the Agilent 6546 LC/Q-TOF. On the left side of the image, you’ll see the part of the machine responsible for breaking down mixtures to be analyzed. After the mixture is broken down, it is sent to the machine on the right which allows for anyone using the machine to see what substances make up the mixture that was broken down earlier

Week 2

Week 2 was spent preparing the background of what my research is about. During the week I prepared slides surrounding my research of PFAS, creating a sheet to calculate cost, as well as using the LC/Q-TOF

Here are a collection of power point/excel sheets to demonstrate what I have been doing!

Weekly Progress Report (July 8th -> July 12th)

I also set up an Excel sheet that will calculate the cost to run one sample for the research. Here, I input codes that would perform the calculations for me. For example, By inputting the code “=(C7/B7)” into the cell D7, it’ll tell you the cost per part used for Silanized Glass Wool. For analyzing the cost of one sample, I entered =SUM() into the cell which gave me the cost to generate a run with one sample.

To wrap up Week 2, I was able to use the machine! Working with Professor Geoffrey Tompsett, we tried to run a test sample however we were stopped during the tuning phase. One of the test reports whether or not a section failed and most of the sections that reported Pass/Fail came back as fails. So far, we think that the equipment needs more of the tuning mix used so Professor Tompsett emailed Agilent (the company behind the LC/Q-TOF) to check.

Disclaimer: This is a test run just to show what I will be eventually using. Later in the program, I will have the actual data with the real part names.

Week 3

For Week 3, I was not able to work on much due to being in Washington D.C. for the 2024 Noyce Summit. What I did work on however was converting the procedure I will be using into a version that is easier to read/follow. Another task that I worked on when I came back to WPI was checking to see if we had enough materials to complete the test run on Monday, once Professor Tompsett comes back. To provide context, last week Professor Tompsett and I attempted to tune the LC/Q-TOF machine. The first tuning was successful, however we then tried to tune the quadrupole part of the machine. In the part of the machine where the mass spectroscopy occurs, there are pieces of equipment called “quadrupoles” that help improve the accuracy of the results. When tuning this part, the machine will let you know if the tuning failed or passed in certain areas. When tuning the machine for the first couple of times, there were categories that we failed on. Professor Tompsett and I agreed that we needed more of the tuning mix, however we weren’t sure which mix belonged to the tuning mix or the reference mix (There were two solutions that could’ve been used). Professor Tompsett emailed me information on how to make the mixtures, so I spent some time trying to see if there was anything needed.

While in DC, I recorded a video which served as an overview on what my project is. This video details the background of my research, the method I am using for my research problem, and how it connects to some of the UN Sustainable Goals.

For RET, another component that must be completed is the lesson plan. At the moment, my lesson plan is in its early stages but I have narrowed down what I would like to work on. First, the standard. The standard that I decided to focus my lesson plan on is:

HS-PS1-11(MA). Design strategies to identify and separate the components of a mixture based on relevant chemical and physical properties. 

• Emphasis is on compositional and structural features of components of the mixture. 

• Strategies can include chromatography, distillation, centrifuging, and precipitation reactions. 

• Relevant chemical and physical properties can include melting point, boiling point, conductivity, and density. 

Seeing as my research includes chromatography, I think that my lesson plan could include chromatography as well so there is an easy connection I can make between what I did compared to what the students will be doing. The hardest step so far has been trying to create an activity. So far, I have come down with two activities. The first activity takes after one of the very first experiments I did when I came to WPI. This lab involved separating the compounds of a leaf through chromatography. The way I imagined this experiment would be that I would classify one of the compounds as a Forever Chemical and have the students try and figure out a way to remove it. After talking with Jay, he gave me a different idea that I could instead have students analyze water in the fountains at school to see if there is anything in them. I am leaning more towards Jay’s idea because I think that this would increase engagement with the students.

Week 4

For Week 4, I have been able to collect data!

Starting on Tuesday, Professor Tompsett and I were able to tune the machine and finally run a test sample using a premade standard of a PFAS known as “PFOA” (Perfluorooctanoic Acid). We ran the sample using the LC/Q-TOF and got the data you see above. This was done by exporting the data into excel and then taking said data and turning it into a graph. The next step for this piece of data is to figure out the concentration of the standard (It is a standard so the concentration is already known, this is more so just for the practice). This is done through the calibration curve.

A calibration curve is made through a series of known concentrations that allows you to create a trendline. Through this trendline, you can make an equation that will allow you to find out the concentration of an unknown sample. For example, if I knew the LC/Q-TOF Mass Peak Area of an unknown PFOA sample, I would rearrange the trendline equation to solve for the concentration (the x variable).

 

Another update is that I have made progress on my lesson plan draft. Wednesday, July 24th, was our professional development led by Rebecca Cooke. We went over creating learning targets and a lot has changed surrounding my lesson plan since the last time I mentioned it. First, my lesson plan has a new activity which is creating a compound to replace PFAS compounds inside of various products. Students will have to first decide on what product (that has PFAS) to research about and find out the purpose behind the PFAS. Then, students will make their own compound to replace the PFAS so that the products/materials are not toxic. So far, I only have the learning targets and vocabulary words, but we have been going step-by-step in creating the lesson plan draft.

As the last update for this week, I have begun to make a my very own calibration curve. Due to the nature of this experiment, I had to make my very own procedure

One of the hardest parts of this procedure was controlling PFAS contamination. If/When a PFAS spill occurs, I had to immediately use methanol and a Chem-wipe to wipe down any surface with the spill. The pipette I was using dripped constantly, however I got around that issue by quickly dropping the liquids into the vials before the drip occurs. I was extremely nervous while working on the dilutions for the calibration curve because I didn’t want to contaminate the lab or myself. As you’ll see in the procedure, there is a lot of material waste. This does not include the fact that every time the PFOS standard (A version of PFAS) touched my gloves, I had to immediately remove the gloves, wash my hands thoroughly, and get new gloves. I was able to make all of the standards yesterday, however there was one issue that was resolved. The vials we were using allowed for a total volume of 1 mL. I tried placing 0.75 mL of the fully concentrated standard into the vials and almost spilled some in the process. From that point on, I divided all of the values I would be using in half, which is the document you see attached. At the moment of this update (July 26th, 8:28 AM) I have not finished the calibration curve due to time constraints however I hope to have them finished today. Depending on when the curve is finished, it’ll either be in the Week 4 section or the first image in the Week 5 section.

 

UPDATE (July 26th, 3:11 PM): After speaking with Professor Tompsett, it turns out that the concentrations listed were too concentrated. The spectra generated from Agilent’s runs were sharp and pointed, with little to no tail at the front and back of the reading. Mine were wider, so Professor Tompsett was confused as to why, seeing as at that moment, we were convinced nothing was wrong. After going back to check the units, Professor Tompsett let me know that we were off by a magnitude of 6 for our concentrations (times 1,000,000). It was an easy fix, diluting the concentrations to the correct amounts, but needless to say it was a hilarious experience. It was also a lesson learned: always check your units.

Week 5

Here are the two calibration curves I made. One is for PFOA and one is for PFOS, the two most commonly used PFAS. The process of making the curves was a little different compared to before, which you can read below yourself!

After discussing with Professor Tompsett, we decided to make a large stock solution from the original PFOA/PFOS standard. This was done by taking 0.05 mL of the original standard and adding 99.95 mL of methanol to dilute the sample. This was to drastically reduce the concentration of the standards because the last time we didn’t, we had to flush the column with methanol for a couple days to remove the PFOA/PFOS contamination. Once the stock solution was made, we then performed dilutions that lowered the concentration at a faster rate. After making the solutions, we ran them in the LC/Q-TOF and got the curves you see at the top of Week 5. I am planning on running the samples again as in the PFOS curve, the third data point is further away from the line of best fit, so I would like to get the R value as close to 0.99 (Like the PFOA curve) as possible.

The focus on this week was making our posters. On Tuesday, July 30th, we presented our posters to the RET group in order to get feedback. For my rough draft, I have been steadily making progress on my poster. I have been trying to incorporate new ideas into my poster as well as ideas from fellow RET teachers and RET staff.

 

Week 6

For the last week of the program, I spent time polishing the poster you’ll see below. I had help from the Teixeira/Timko lab group at WPI, and they gave amazing feedback which help shaped the poster on this page. Being a part of this program has been an amazing experience that has put a new perspective on what research is. While I knew that research wasn’t something that could be done overnight, I never knew how long it would take in order to work on one step of a large research topic.

 

Final Poster

RET Lesson Plan Draft