Environmental Analysis Lab

Over the course of the past year encompassing summer 2016 through spring 2017, one analytical instrument in the Environmental Analysis Lab has seen more use than all the others – the Flash Elemental Analyzer (EA) (see pic). All work noted below was done using this one instrument, which allows us to quantitatively analyze the total carbon (C), nitrogen (N), sulfur (S) and/or hydrogen (H) of powdered solid samples or liquid samples.

Early in the summer, Mary Ignatiadis ’16 (Geosciences), wanted to reanalyze some samples from her honors thesis work, which focused on historic charcoal-making mounds in Connecticut. Mary hoped to show that carbon/nitrogen (C/N) ratios were significantly different in samples collected in the mounds compared to nearby soils. Mary’s work was supplemented by the CES lab summer Research Assistant (Jake Foehl ’19) who analyzed numerous splits of Mary’s samples to better quantify analytical accuracy and precision. When the semester began in September, various student groups from CH255 (Ford lab – Prof. Sarah Goh) used the Flash EA to try and determine the C, N, S and H content of their unknown samples. Many revisits that included re-analyses occurred during this time since the students were not always convinced of what their compounds contained! A dozen GEOS 411 students taught by Prof. Phoebe Cohen

used the Flash EA for N, C and S determinations of their Winogradsky columns. A senior Biology thesis student, Diana Sanchez ’17 from Prof. Manuel Morales’ lab analyzed C/N ratios of some 400 samples of ground up plant material in her study of Treehopper mutualism. Working alongs

ide Diana, another student, Zeke Phillips ’18 (Geosciences) from Prof. Phoebe Cohen’s lab used the Flash

EA to study the amounts of C and N in Precambrian microfossils extracted from rocks collected in the Yukon Territory. During this time of heavy use the Flash began to fail – the nitrogen background was too high and masked measurements of N and C. After days of struggling and a site visit by the company technician (which included a preventative maintenance routine), we discovered that a setting in the machine software was the culprit. Once reset, the Flash was back to performing in top shape. Nigel Bates ’17, a senior Biology thesis student, used the Flash EA to analyze C/N ratios in hundreds of soil and leaf litter samples collected

from the Beinecke stand in Hopkins Memorial Forest (HMF) under the guidance of Prof. Hank Art (Biology). Nigel had the challenging task of analyzing more than 500 different samples collected then compiling and analyzing the data to better understand how old-growth forests and soils sequester carbon. All told over the course of a year, more than 2200 Flash EA analyses were collected by three different departments, encompassing both independent research and class laboratory exercises.