This document describes a study that used ion chromatography to test outdoor water samples around a college campus to determine if anion levels met EPA criteria. Water samples were collected, allowed to settle, and prepared for analysis. An ion chromatography instrument separates ions in a sample column and measures ion concentration through conductivity. The instrument was calibrated by generating calibration curves for ions of interest using standardized solutions. Samples and calibration standards were run through the instrument to identify and quantify levels of sulfate, chloride, nitrate and fluoride ions and compare them to national standards.

1. Purpose:
Test and analyze outdoor water
samples around the Harper campus
to determine if the levels of
permissibility of the anions meet
the criteria of the EPA.
Ion Chromatography
A sample is injected into the
instrument and goes through a
column. When the sample is in the
column, the ions are separated. Ion
concentration is then measured
through electric conductivity.
Instrument Calibration
The Ion Chromatograph is calibrated by
generating calibration curves for the anions of
interest. Ions are then identified by the time it
takes the ion to get to a detector within the
machine. Methods were generated so that
each ion had a different retention time. For
the Ion Chromatograph, the concentration of
an ion is proportional to the conductivity of
the ions in the solution. The standardized
solutions of the four anions made were used
to create graphs of concentration vs.
conductivity. From these graphs, best fit
equations were obtained to allow us to
calculate the concentration of an ion, given
the conductivity. The calibration was checked
several times throughout the year.
Identification of Anions
0.5g of four different substances were combined with 100mL of water
(H2O) to form four different compounds of stock standard solutions.
These substances were sodium sulfate (NaSO4
2-), sodium chloride
(NaCl-), sodium nitrate (NaNO3
-), and sodium fluoride (NaF-). After,
2mL, 3mL, 5mL, and 10mL of each solution were extracted from the
compounds and placed into 100mL volumetric flasks. Then, 3 vials of
each concentration of each compound will be filled, coming to a total
of 72 vials. Lastly, all 72 vials ran through the machine along with 2
blanks at the beginning and end of the sequence. Blanks are vials filled
with ultra pure deionized water used to detect any abnormalities
within the machine.
Retrieval and Preparation of Outdoor Samples
Using rubber gloves and bottles, we took our water
samples. At the sample site, we filled and emptied the
bottle three times. By doing so, we ensured that the
sample was not contaminated from previous samples taken
using the same bottle. After being acquired, samples were
allowed to settle for about three days. This helped to
prevent any materials found in the samples from blocking
the flow of the Ion Chromatography machine. Then, two
vials of each sample were prepared, coming to a total of 28
vials including the 4 blanks.
Anions Analyzed
Sulfate (SO4
2-), Chloride
(Cl-), Nitrate (NO3
-),
Fluoride (F-)
References
EPA. "Title 35: Environmental Protection Subtitle C: Water
Pollution Chapter I: Pollution Control Board." EPA. EPA, 28 Jan.
2008. Web. 2 May 2011.
<http://www.epa.gov/waterscience/standards/wqslibrary/il/il_5_c
302.pdf>.
Google. Photograph. Palatine. Google. Google. Web. 2 May 2011.
<http://maps.google.com/maps?hl=en&tab=wl>.
National standards
Sulfate 240 mg/L
Chloride 250 mg/L
Nitrate 10 mg/L
Fluoride 15 mg/L
Analysis of Water Using Ion Chromatography
Brittany Bochenko, Ivan Rojas
Dr. Thomas Dowd
Department of Chemistry, Harper College Palatine, IL 60067