Amelya Staiano slices fresh corn from a cob in a Smith Building lab. Next to the corn sits a flask of cubed sweet potatoes. A rising junior who already holds an associate degree in baking and pastry from Johnson and Wales University, Staiano is prepping food, but not for serving. Instead, she plans on analyzing the raw produce to see if it contains pesticides.
Specifically, she wants to isolate and quantify the compounds glyphosate (the active ingredient in the weed killer Roundup) and aminomethyl phosphonic acid (another commonly used herbicide, typically referred to as AMPA). The overall goal is to help health-conscious shoppers answer an oft-troubling dilemma: Are organic foods worth their higher price?
It’s a question that her research partner, chemistry professor Shakena West, says she asks herself nearly every time she goes to the supermarket.
“Of course you have organic and conventional fruits and vegetables, and you think to be healthy you need to buy organic,” Dr. West says. “But is it really any better, especially when you are trying to stay within the grocery budget? So I thought it would be a good research project to find out.”
According to her proposal for a Reeves Summer Research grant, shoppers often pay 30 to 60 percent more for produce that is labeled USDA-certified organic, a designation that means it has been grown on soil that has not been treated with pesticides, sewer sludge or synthetic fertilizers for at least three years. West says published studies have investigated the amount of pesticides found in the soil where crops were grown and harvested, but she wants to figure out how much glyphosate and AMPA actually wind up in the food.
It’s a complicated feat, but one that she feels Staiano is up for. “She has been excellent,” West says. “In fact, she found in the literature the method we are going to be using for detection.”
Initially, the professor considered using gas chromatography and mass spectrometry to detect the compounds, but because the compounds have extremely high boiling points, getting them into a gaseous state wasn’t feasible. Instead, they are using High Pressure Liquid Chromatography with a UV detector, but first tagging the substances with a compound that will enable them to absorb UV light.
Before they even headed to the supermarket, there was lots to do in the lab. They had to become proficient in using the University’s High Pressure Liquid Chromatography machine, nicknamed Elsie. And they had to figure out the smallest concentration of pesticide that the equipment could detect so that they could create a calibration curve that covers the appropriate concentration range.
Figuring out the curve involved a bit of trial and error, with Staiano working the math to create solutions of various concentrations and then figuring out how to process them so that the HPLC accurately measures how much glyphosate or AMPA are present in each. The fact that she’s majoring in both chemistry and math made the work easier, as has West’s hands-off approach.
“When I did both my undergrad and grad research, my professors had this as the goal: train me on a new technique or procedure to their level of satisfaction and then being comfortable enough to let me do the work,” West says. “This gave me a sense of ownership over the project and really helped develop my confidence in my laboratory skills. So that’s what I want to do with my students.
“Amelya did the math, worked it out, and I sent her on her way. I think it’s really important to do that, to let the student know, ‘You’ve got this. You have been taught, and you know what to do.’”
Learning from failures
Staiano says the freedom to work on her own has helped build her confidence, and she says she has loved the experience of working one-on-one with her professor.
“I am the kind of person who loves to ask a lot of questions, but now I am getting to the point that at times when I ask a question, I will think, Wait, I already knew that,” Staiano says. “This is helping me back up and realize all the things that I already know and how they apply to the problem I am working on.”
She expects the summer research with West to put her ahead of the curve next semester when she takes analytical chemistry, and she looks forward to presenting the pair’s findings at Wingate’s Wellspring Symposium and at the Southeastern Regional Meeting of the American Chemical Society. Plus, she says the trial and error can be fun.
“You actually learn more from your failures than if it all works the first time you do it,” Staiano says.
Back in the lab, she’ll soak some of the chopped veggies in water, grind up some in a food processor and dehydrate the rest, trying to determine how best to extract the pesticides, so they can be isolated, tagged and measured.
While she concentrates on the task at hand, like any good scientist she’s also thinking ahead to the next question.
“I am excited about being able to take our discoveries and apply to foods outside of produce,” Staiano says. “Being a pastry chef, it would be interesting to see if any of these pesticides can be detected in eggs or flour.”
She and West are among seven Reeves Summer Research teams busy on campus this summer.
July 1, 2019