Internships

Spotlight

2020 intern

Alex Mikulich, 2020 NASA Goddard Space Center Intern

AUG 10, 2020

Biography

SPS Chapter: Colorado School of Mines

I am an engineering physics major born and raised in Colorado. I enjoy snowboarding, cycling, and racquetball. I have also developed an interest in computer science, and I hope to pursue a minor in that field. I love the applied and experimental parts of science, and I will continue with engineering in graduate school. I am currently doing research with NREL through the mechanical engineering department at my university, and also working with a nuclear physicist to design and construct a neutron detector mount to be used in an experiment at TRIUMF this coming winter. I love the innovation and design process, and hope to apply my skills in the technology field one day.

Internship

Host: NASA Goddard Space Flight Center

Project

Abstract

Use of laser desorption ionization (LDI) for mass spectrometry requires careful deposition of the analyte onto the laser target. Specifically, performing quantitative abundance measurements of biomarkers or abiotic organic materials (with or without matrices promoting ionization of unfragmented ions) requires reduction of variations in the mass spectrum intensities resulting from spatially inhomogeneous targets. Additionally, coupling of LDI to liquid based separation methods (e.g. chromatography or electrophoretic) can be done by continuously spotting the concentrated eluate onto a moving substrate and, later, extracting retention times of these analytes by examining the spatial variation of the composition of the deposit. Uncontrolled wetting of the substrate leads to poor definition of retention time while deposition of well-defined spots improve calculated retention time. Direct deposition of eluate using a capillary or pipette, the dried droplet method, is sensitive to the substrate surface roughness, substrate-solution interaction, and gravity. In particular, the formation of a ring during drying is found to occur regardless of surface chemistry and results in the so-called “coffee stain” effect. For these reasons, airbrushing through stencil masks presents an attractive method for improving both the spatial homogeneity of the deposition and reducing the spot size of the deposited analyte over the simpler dried-droplet approach. Initially, the researchers tried using a micropipette to deposit small amounts of rhodamine onto a stainless steel plate. Then, several variables were altered, including solute concentration, solvent type, plate temperature, and the delivery method. It was found that if the solvent were quickly evaporated after the droplets hit the surface, the solute molecules did not have enough time to migrate to the edges. Thus, isopropanol as a solvent helped reduce coffee staining. This was further improved by heating the sample plate to a temperature between 100 and 150 degrees Celsius. The tiny droplets that were atomized with the airbrush vaporized on contact, and thus a homogeneous deposition could be achieved. The use of an airbrush also allowed for smaller spot sizes. Even with a 0.5 microliter droplet from the pipette, the spot size was still several millimeters in diameter. An airbrush, coupled with a stencil, was able to give clearly defined spots measuring as low as 200 microns. Therefore, when performing mass spectrometry with LDI, airbrushing the solvent onto a hot plate through a stencil can offer significant improvement over a dried-droplet method.

Final Presentation

Alex Mikulich Final.pdf (.pdf, 1 mb)

Internship Blog

Week 1: Starting my experiments!

I can confidently say that I am going to enjoy my summer with NASA! So far, I have attended several orientations with all types of interns, including both from NASA and from SPS. I have interacted many times with the SPS interns; they are amazing people and I look forward to working alongside them for the next 10 weeks. We have made many efforts to get to know each other, even playing games over Zoom in the evening. I was worried that being restricted to online communication would hinder us, but now I think we will be just fine.

Regarding my work with NASA, I have chatted at length with my advisor, Dr. Adrian Southard. We will be working on a project that aims to develop a fluid trap for detecting life in icy environments. I am excited to work with him because he had a similar background to mine, in that both of us entered college wanting to do theory-based work and ended up finding a passion for the experimental process instead. One of my goals for this internship was to make connections at NASA and find out more where my interests lie, and Dr. Southard told me that he would help introduce me to as many of his fellow project heads as possible.

I purchased an airbrush kit for this project, and Dr. Southard’s first task for me was to perform experiments into the droplet size that it produced when sprayed onto a plate. The goal is to ultimately apply a solvent onto a surface and to search for various organic molecules. Earlier this week, I set up a small paint range in my bedroom that I could use to perform several trials with the airbrush. I happened to have a hobby vice clamp that was perfect for holding the pen at precisely the right angle, and I bought a digital microscope to analyze the droplets. I decided to corellate the droplet size with air compressor PSI, and found a pretty clear negative corellation (I attached the graph below). I wrote my results up in a formal, lab-style report, which is probably more than necessary but I want to be as professional as possible. This is my first major internship, and I want to contribute as much as I can to it!

Overall, I am excited to speak with my advisor again and will report back next week!

Results - Week 1

Week 2: More experimentation!

My second week has gone well! I have met more with my mentor, Dr. Southard, and also with Dr. Xiang Li, another researcher at Goddard. They took a look at my earlier experiment and made some suggestions to improve it. Rather than droplet size, I should have allowed it to dry and looked at the profile of the deposited substrate. I did some more testing with salt water, and found that when using droppers, we get a ‘coffee stain’ effect where the substrate clumps in rings around the droplet instead of evenly across the surface. I used an airbrush, and found that the shorter the spray duration was, the less noticable this effect was. I am currently writing up the results in LaTex, so it gives a professional touch to my findings.

I have also been a part of a small book club that reads a chapter out of an astrophysics textbook every week and discusses what we learned. Much of it has gone over my head, as I am not specializing in astrophysics, but I am learning plenty of details about detectors, telescopes, and spectroscopy that I did not know before. I am thankful for this internship, as it has given me an amazing insight into the world of space, research, and experimentation.

Week 3: Research with propanol

My third week of the internship is proving eventful. I have done more testing with my airbrush, including applying isopropyl alcohol instead of water as a solvent for salt. I have also done tests regarding how fast the solvent evaporates as a function of the spray duration, heat of the hot plate, and also tested the volume of liquid that comes out during short bursts.

I have also met more with my fellow interns over Zoom, and I also got to talk more with some faculty, including Brad, Makaela, and Kayla. They are all very nice people, and I am really happy to be working with them. I also met with my astronomy book club on Friday, and made a presentation about scintillation detectors and photomultiplier tubes. Overall, I have had a good week, and learned plenty along the way!

Week 4: Working with chemicals

This week has been pretty exciting, I have moved on from working with salt water and salt propanol to working with rhodamine-6G. When I ordered it off the internet, it came with a safety sheet that recommended a fume hood and a formal laboratory, but all I have is a garage and work table. My mentors have assured me that it is okay to work with as long as I use gloves and wear a mask, which is what I did. I have been conducting more tests over the weekend into the coffee stain effect, and rhodamine should give us more insight, as it is flourescent.

I have also met with my other interns for bad physics movie night, where we watched The Core together. We have to make a 60 second video about the scientific inaccuracies, which I am looking forward to. After that, I will make a physics-related demo for the SOCK competition for AAPT. One thing that has always fascinated me is gyroscopes, and how they work. I know that bicycle wheels are a great way to demonstrate the effect, and look forward to filming it.

Overall, I am happy with my progress and look forward to more experimentation!

Further testing into the coffee stain effect

Shorter blog post this time. It is hard to believe this has been my fifth week of interning at NASA! I have had a great time so far with all of my other interns, and my tests have been going well. I did some research into the coffee-stain effect, which is what I am trying to minimalize when I spray solvents onto a surface. It turns out that it is caused because liquid near the edge of the droplet evaporates faster and liquid near the center, causing a flow of solute to the edge. One solution I am testing is using liquid with less of a contact angle, so that all parts evaporate more evenly. I also used rhodamine, and bought a UV light bulb to see residue a bit better (see the picture at the end).

My next steps include renting a thermal imaging camera to see if airbrushing a sample plate on a hot plate will significantly cool it off. I will also be testing the rate at which a liquid evaporates vs. the coffee stain effect.

Week 6: Stencils and getting my own lab

I have just finished up my sixth week, where I managed to snag a lab at my university to work in for the summer. I reached out to a member of my university’s Environment, Health and Safety office and they managed to get me my own workspace in the basement of one of their buildings. I am currently working in a chemical waste storage room that has much better ventilation than my garage, so I am optimistic that I will get more work done. I am also going to be able to order some CHCA and DHB, which are two chemicals used to form MALDI matrices. I wasn’t able to get them before because the company does not ship to private individuals, only bona fide labs.

This last week, I mainly worked on stencils. Specifically, I wanted to see if it was possible to get a small spot size with an airbrush. Usually, it is is hard to do this because when putting the airbrush close to the target, the jet of air spreads the droplets out. I looked up common airbrushing techniques to get small spots, and they indicated that stencils are the only way. I went ahead and did some tests with this, and found that I could get spot sizes as small as 200 microns in diameter. I will be doing more work in the future to reduce coffee staining in these droplets, and am excited to be working in my new lab!

Week 7: Working in the lab

Short blog post today. The biggest goal right now is acquiring CHCA and DHB for testing in the future, and this is tricky. The company I am ordering from will only ship to laboratories, and my university is having trouble ordering it because of insurance reasons, as I am not technically doing this work for campus purposes. I am very grateful to the people at my university for going above and beyond to help me out, but I may have to go the summer without it.

Besides the lab work, I have been doing some research into the photoelectric effect. This is because the MALDI matrices are used with lasers, and the photons from the beams can cause photoelectrons to travel throughout the target plate, which could then ionize the molecules. Since we are using UV lasers, the light will be strong enough to work function. One of the aspects to consider is how the thickness of the foil affects the photoelectric effect, as thicker foil will have more atoms in the path of the laser beam, and I made an equation based on the mass absorption coefficient of iron that should indicate how many photoelectrons are emitted. I have typed up my results in a Latex document, and am excited to share it with my advisor.

Week 8: Finally, some good results!

Another late entry! I have spent my week going to the lab at my campus, it is has finally paid off. To recap, the goal for me was to analyze methods of depositing solvents for use with LDI mass spectrometry. I wanted to get a homogeneous distribution of solute, and also wanted to minimize the spot size. With a dropper, you can make droplets on the surface but when they dry, they leave behind uneven rings. This week, I finally found a way to do this. The formula is:

Airbrush instead of micropipette
Use a stencil
Raise the stencil 1.75 mm above the target plate
Place the target plate on a hot plate heated to 150 degrees Celcius
Use isopropyl alcohol as a solvent instead of water
Hold the airbrush 4 cm above the stencil

When following these steps, it is possible to drastically improve spacial homogeneity and decrease spot size. The smallest size with the dropper was only about 3 mm, whereas I was able to get a diameter of 0.3 mm with the stencil. I went ahead and uploaded a side-by-side comparison between the dried-droplet method and the airbrush.

Overall, I’ve had a great week with my experiments and look forward to continue the research!

Week 8: Finally, some good results!

Airbrush instead of micropipette
Use a stencil
Raise the stencil 1.75 mm above the target plate
Place the target plate on a hot plate heated to 150 degrees Celcius
Use isopropyl alcohol as a solvent instead of water
Hold the airbrush 4 cm above the stencil

Overall, I’ve had a great week with my experiments and look forward to continue the research!

Week 8: Finally, some good results!

Airbrush instead of micropipette
Use a stencil
Raise the stencil 1.75 mm above the target plate
Place the target plate on a hot plate heated to 150 degrees Celcius
Use isopropyl alcohol as a solvent instead of water
Hold the airbrush 4 cm above the stencil

Overall, I’ve had a great week with my experiments and look forward to continue the research!

Week 9: Presentation

I have finally presented my project for the first time in front of a panel of Goddard Space Flight Center personell. I got a chance to get some feedback about what worked and what didn’t. They enjoyed the pictures that I included, and said that I should include more explanation about the purpose of the projects. I added more commentary about how LDI mass spectrometry can be applied in NASA programs. I also got a chance to present the slides again on Friday, this time to an astronomy book club.

As for testing, I did some more work with minimizing the coffee stain effect. One of the bits of feedback I got was that for LDI, water is commonly used as a solvent instead of propanol, so I redid some of the experiments. I noticed that the results were not as good as the propanol in terms of homogeneity and spot size, but that airbrushing over a hot plate was still a superior method to using a dropper. I also got some feedback that LDI is used with analytes that have a surface concentration of only 1 picomole per square millimeter, so i did some experiments to replicate those concentrations.

Finally, I got to meet again with my fellow interns on Thursday. We mostly talked about how our summers were going, and a few of them are coming to Colorado, so I might get to meet them!

Week 10: Presentations

This will be my last blog post for the summer, as my internship has officially concluded. I spent this last week presenting my progress to a few NASA personell and plenty of SPS guests. I talked about the background of LDI mass spectrometry and the drawbacks of the dried droplet method. I then showcased my results that showed the improvements in homogeneity and spot size, and I think the presentation worked well. I got plenty of good feedback, and found out afterward that three of the top solar system researchers at Goddard showed up!

As for the experimental work I’ve done this week, I repeated some of my earlier tests while using a hot plate. I tested different distances from the airbrush to the stencil and found that smaller stencil holes require closer distances to get ideal spots. I also tested different solutes to make sure that the homogeneous results I got didn’t only apply to rhodamine. I found that the method I was using, airbrushing over a hot plate using a stencil, also worked with organic molecules and salts.

Overall, I had a fantastic summer, and hope to keep working for NASA in the fall!