Determination of Iron in Abandoned Mine Drainage by UV‐Vis Spectrophotometry and Flame Atomic Absorption Spectrophotometry

Abstract

This paper describes and compares the results obtained from determination of total iron in abandoned mine drainage (AMD) from selected sites in western Pennsylvania by UV‐visible spectrophotometry (UV‐Vis) and flame atomic absorption spectrophotometry (FAAS). As our laboratory possesses both methods, the accuracy and precision of iron results by UV‐Vis, using iron (II) chelator 2,4,6‐tripyridyl‐1,3,5‐triazine (TPTZ), and FAAS are of interest in the event of instrument problems with either method. Calibration curves show excellent linearity (R ²≥0.990). The results show good accuracy (complete recovery of spiked iron) and precision (0.5–3.4% RSD by UV‐Vis, 1.5–7.7% RSD by FAAS), indicating both methods are suitable for determination of iron in AMD. This comparison study is presented as a potential approach to teaching students about UV‐Vis and FAAS and their advantages and disadvantages.

Keywords:

• Abandoned mine drainage (AMD)
• flame atomic absorption spectrophotometry (FAAS)
• iron
• student project
• 2,4,6‐tripyridyl‐1,3,5‐triazine (TPTZ)
• UV‐visible spectrophotometry (UV‐Vis)

Acknowledgments

The authors acknowledge the continued support of the Natural Sciences Division of the University of Pittsburgh at Greensburg (UPG). The authors are grateful to the Society for Analytical Chemists of Pittsburgh (SACP) and the Spectroscopy Society of Pittsburgh (SSP) for funding of the UV‐visible spectrophotometers in our laboratory. M.T.S. acknowledges Koko's Greenhouse (PA Route 837, Elrama, PA) for permission to park at their facility while collecting AMD from the nearby sites and for a sample of their well water for iron determination. The authors thank an anonymous donor of a large quantity of plastic centrifuge tubes for collection of AMD samples.

Notes

The authors were invited to contribute this paper to a special issue of the journal entitled “Undergraduate Research and Education in Spectroscopy”. This special issue was organized by Associate Editor David J. Butcher, Professor of Chemistry at Western Carolina University, Cullowhee, North Carolina, USA.