Chapter Nine: Well Shucks, NAU Students (feat. Melanie, Jeff, Jamie, Bryden, Sabrina)

As you all know, the Colorado Plateau Stable Isotope Lab/Colorado Plateau Analysis Lab takes samples from clients and analyzes them for concentrations of different compounds: nitrate, sulfur, potassium, and many more. In water, it's important not only that there aren't compounds like nitrate and phosphate (that are not only toxic to humans but also promote algae growth, causing DBP buildups) but also heavy metals like chromium and lead that are much more toxic than the former. Thus, the lab on occasion receives samples of water for heavy metal analysis using our Flame AA machine - sometimes from paying clients, sometimes from environmental classes at NAU doing projects.

This week, we received water samples from two NAU classes asking for that very same type of analysis - chromium and lead in the Flame AA - and boy, was it a tough one. Like all samples, we have to do dilutions of the raw samples so that we can add in the analysis standards, but it becomes tricky when said raw samples have such low levels of the ion in question that dilution makes it impossible to even sense that ion!

The two classes' samples - 31 in total!

We started with a 1:100 dilution and got nonexistent readings, so we reduced it all the way down to a 1:2 dilution!

After we ran the 1:2 dilution through the machine, we found that lead in the samples was mostly detectable, whereas chromium was still in tiny amounts!

So this next week, we'll be doing more of the Flame AA, trying to fix the dilution ratios. Hopefully, the next time students send in samples, they'll have detectable amounts of ions.

 This past week, I also continued with the digestion of that soil sample, and we'll continue that this next week. And lastly, as I usually post on Monday, I've started on a pretty important but (quite possibly the most) disgusting operation: that'll be in next week's post.

Thanks for reading! Remember that my SRP presentation is on Saturday, May 6th, at 4 pm! Also, I'll be finishing that up within the next week! I'm not sure if I can actually publish it online (for CollegeBoard purposes), but feel free to shoot me an email at lucascrane11@gmail.com if you'd like to read it!

End of Chapter Nine.

Chapter Eight: Weighing Dirt Is Hard, Man (feat. Melanie, Jeff, Jamie, Bryden, Sabrina)

Remember a few posts ago, where I said that I was really bad at keeping my hand steady? Remind me to eat well so that I don't shake when I'm creating microwave acid digestion bombs.

Let me explain: no, I didn't burn myself with acid. This week, I did some digestion prep for soil and sediment samples - I spilled dirt, nothing serious.

Being able to do this part of the process was especially interesting because I've already cleaned digestion tubes after the actual digestion and testing! Here's how digestion works:

First we load up about 2 milligrams of each soil sample into these tubes (which caused quite a mess) so that it'll be easier...

To load about 0.4 milligrams of the samples into the microwave "bombs." They're not actually bombs, but they are incredibly pressured, so the name sticks.

We add the sample into the bombs...

and add some different concentrations of acids...

that we need to be precise with, so we have this here auto-pipette!

The acids, however, produce toxic fumes, so we keep them under a fume hood.

Using this tool to tighten the bombs into their holders...

Using this spin-wheel, we insert the bombs into the microwave, where they get heated and pressurized, causing the soil to break down into liquid.

After transferring the dissolved soil into new tubes, we clean the bombs with distilled water and dunk them in this nitric acid bath.

After all of this is done, we'll run the liquid through this machine...

Which blocks out every wavelength of light except for the wavelength of a particular ion. We run the samples through the machine, and the change in the light intensity is measured.

 And that's essentially digestion! Besides that, I've worked on NAS trays. I'm also still waiting to hear back from that professor, so I'll hopefully have that in next week's post. Additionally, Jeff ran my samples through a denitrification machine to get another reading on how much nitrate is in my sample! He's yet to compile the results, so that'll also hopefully be in next week's post.

Thanks for reading! Remember that the day of Senior Research Project presentations is May 6th, from 9-4:30 (or so). Mark that date on your calendar!

End of Chapter Eight.

Chapter Seven: Dropping Flames All Over The Lab Game (feat. Melanie, Jeff, Jamie, Bryden, Sabrina, Chris Lamb, Alicia Vaughan, Heather Bigley, Fellow AP Researchers)

The lab got pretty hot this week, as it featured some major fire! No, I didn't drop my mixtape in the lab, though I bet if I had a mixtape, it would be straight heat. While the mixtape would have to have some rap for it to be fire, it would probably have some indie, classical, and jazz influences just because I probably wouldn't be able to put out a fully hip-hop/rap album that was actually good.

In all seriousness, this week, besides the usual Natural Analytical Standard trays, I got to run my water sample and the other water samples from hot springs through the Flame Atomic Absorption Machine! The machine essentially runs like so:

We first create standards to run through the machine for the same purpose that we run standards through the Ion Chromatography Machine: we create a calibration curve using known amounts of standards and then compare water samples to that curve.

The standards, all in different dilution amounts.

We then run the standards through the machine. The machine essentially shoots light coming from a bulb with filaments made out of different ions (sodium, potassium, calcium, magnesium, etc). The light reflects off of mirrors and passes through a sensor to give us a strength reading.

The light sources come from these bulbs - the red filament in the picture is made of sodium.

We turn on a flame that the light passes through and start siphoning different water samples in through a capillary tube. The ions in the water go into the composition of the flame. If we're running sodium as the light source, sodium in the water will go into the flame and will in turn interact with the strength of the light source passing through the flame, giving us different readings. As an added bonus, different materials create different-colored flames! Pretty cool, if you ask me.

This capillary tube will suck in water samples.

And different colors of flames will come out of it!

As a precaution for flames that emit dangerous amounts of UV light, we generally look at the flame through this UV filter on the front of the machine.

There was even a pink flame!

The results of the Flame AA tests.

So why do we do both the Ion Chromatography tests and the Flame AA tests? Well, good question! The IC tests look for concentrations of anions (fluoride, chlorine, phosphate, sulfate, nitrate, etc), whereas the Flame AA tests look for concentrations of cations (sodium, potassium, calcium, magnesium, etc). It really depends on what you want to find out about the water! For example, large levels of calcium will generally mean that there are large amounts of limestone runoff in the water source.

And what do these results mean? Hopefully, find out next week! I have the data showing the concentrations of cations and anions, but this next week, I plan on contacting a professor at NAU to help me interpret the data. If the data is interpreted in next week's post, you'll know that the professor was willing to help!

Besides the Flame AA tests and the NAS trays, I presented my research findings for my AP Research class! If it's allowed, I'll see about obtaining and posting that video on here. However, if you want to see that presentation mixed in with the rest of my internship, come see my SRP presentation and the rest of my classmates' presentations on Saturday, May 6th. The first presentation starts at 9 am; my presentation is last, at 4 pm.

Hope to see you next week!

End of Chapter Seven.