A Day in the Lab

6 Aug

Hello! It’s Maya Domeshek of the Paradise Pond Sediment Sluicing Project again.

Last time I told you a bit about lab work and lab machinery.  But today I’d like to tell you about the other thing I’ve been learning this summer—Database Building.  As I’m sure you know, almost everything in our lives involves data management.  A good example is the college itself.  It has to keep track of people (students, faculty, staff) and money (salaries, tuition, aid) and also institutional information like grades and classes.  When there are so many different kinds of data connected in so many different ways—students have classes, grades, teachers, and tuition and teachers have classes, students, and salaries—a simple spreadsheet is not sufficient.  You build a database.

The Pond Project does not require anything so complicated as the college’s Banner Web system—which is good because I’ve only just started learning about Databases—but it’s just complicated enough that a flat file database won’t work.  I first became interested in databases when I noticed that we were having trouble keeping track of all of the sediment data we were collecting.  As I explained last time, most of my work has been determining the metal concentrations in the pond sediment.  Our method involves extracting the metals by digesting the sediment samples with acid and then analyzing the liquid with the ICP-OES (Inductively Coupled Plasma spectrometry- Optical Emission Spectroscopy).  In order to check our method, we have been running multiple extractions on some sediment cores to see how variable our extraction process is.  We have also been doing multiple ICP analyses on some extracts to see how variable the ICP is.  Unfortunately, the database we were using didn’t have a way to distinguish these different kinds of replicates, which made it hard for us to quantify the different kinds of error in our procedure.

This struck me as a problem worth fixing, so Bob (i.e. Professor Newton my research advisor and the new director of CEEDS) has kindly let me take some time out of my regular work to learn how to program a database in his preferred database system—Filemaker Pro.  I finished a first version of it last week in which the database could at least tell the difference between samples that had been extracted repeatedly and samples that had been analyzed repeatedly.  The next step is to get the database to average the metal concentrations of the different kinds of replicates and calculate their standard deviations.  That has required me to start learning about relational databases—databases that can associate a record in one table with one or more records in another one.  In our college database example, there might be a table with a list of students and one with a list of classes but each student can have multiple classes and each class can have multiple students so you might want to organize it as a relational database.

Anyway, once I had my first version of the database up and running with all the data in it, I could finally look at all of the metal data we’d been collecting.  And when I did, there was a new problem glaring right back at me—whenever we ran the same extract of a sample through the ICP and then did it again some time later, the later analysis would have a lower metal concentration than the first.  This meant that the metal concentration in our extract solutions was going down over time, probably because the metals were precipitating out.  With the new knowledge from the database, we can now revise our method to keep a consistent and small amount of time between our extracts and analyses.  Then we will have more accurate data on the metal content of the pond sediments so that we can get our permits and begin experimenting with sediment sluicing.

Also I now have a question for the chemistry department—why is it that some metals precipitate out of an acidic solution faster than others?

-Maya Domeshek ’18 has just finished her work on the Paradise Pond Project as a CEEDS-supported Summer Undergraduate Research Fellow with Professor Robert Newton.  She has not yet settled on a major, but in her free time she enjoys dancing, dance teaching, and sharing a meal with friends and family.

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