Ely and Amelia are working on prepping samples for the XRF!

Hello from Ely and Amelia!

We’ve been hard at work getting samples ready for the XRF machine at UVM! We have been focused on the Puerto Rico and Dominica samples in the lab.

This meant that we spend a lot of time in the lab getting samples prepared. For me (Amelia), it was the first time I had worked with acid on leaching samples in the lab. Samples that had already been collected are brought to the lab and then the grain coating is separated from the grain using HCl. The grain coating of the grain has many of the FRN’s we are looking for, so seperating from the grain is an important first step. Then, due to the acid used in the process, the sample, both the grain coating and the grain, must be neutralized so it doesn’t destroy our brand new oven. This involved rinsing the grains completely with water to remove the acid and titration the acid/grain coating mixture with a base, NaOH. I found the process to be a lot of trial and error but am getting the hang of it! The samples were then dried in the oven and transferred to containers to be run!

This is a sample from a Puerto Rico watershed that has just been leached! The grain coating is the yellow sludge part!

Here is our oven (named Quincy) full of drying samples. The white part on the beakers is neutralized salt from the titration and the the darker part is the grain coating. 

While at UVM, we have been hard at working running samples through a machine called the XRF. Mae Kate, an ObieGeomorph alum, has been training us to prep and analyze the samples that we are planning on running. Preparing our samples to be run involves transferring them into small plastic containers. This can be a tedious process, as the openings on these containers are small, and our leachates are often very tough to break up. Thankfully, only a small amount (2-3 grams) of each sample is needed to obtain all the info we need. The XRF can give us the element composition of the samples, for example, we can find out that a particular samples contains 5% Fe. We can use this data to learn more about sediment transport and whether a sample has a typical composition.

The samples are being transferred into smaller containers for the XRF by Monica (left) and Amelia (right)! Monica is also at UVM running the XRF! 

Here is Ely running the XRF machine!