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Amy E. Witter

Professor of Chemistry

  • B.A., Wellesley College, 1987
  • Ph.D., UC Davis, 1996

Contact Information

  • Phone: 717.245.1681
  • Email:
  • Location: Stuart 2109



Areas of expertise:  Analytical Chemistry; Environmental Chemistry

  • Modern Chemical Analysis w/lab (CHEM 243)
  • Senior Seminar (CHEM 490)
    • Destroy Build Destroy: An Introduction to Chemical Instrumentation
    • Environmental Toxicology & Chemistry
    • Bio-analytical Chemistry
  • Introductory General Chemistry (CHEM 131, 132)
  • Environmental Chemistry w/lab (CHEM 210) 
  • First-Year Seminar (FYS)
  • Integrated Laboratory (CHEM 352)
  • Accelerated General Chemistry w/lab (CHEM 141)
  • Chemistry for Non-Majors w/lab (CHEM 111)
Information for Students

How to get in touch with me: 

This semester (Fall 2018) my office hours are Mondays 10:30-12:00 pm and by appointment.  If you need to make an appointment, please email me three possible times you are available to meet, and I will check my schedule and get back to you with a time.

Approval of Forms:

Study Abroad forms – please first contact me via email to discuss your plans.  Once we have talked, you can send me the link to the Global Education forms to fill out.  Please allow at least one week to complete these.

Pre-health forms – please first contact me via email to discuss your plans.  Once we have talked, you can send me the link to the pre-health forms to fill out.  Please allow at least one week to complete these.

Enrollment at another institution forms – if you are asking to take general introductory chemistry at another institution, you need to contact Rebecca Connor ( to complete these forms.  If you are asking to take organic chemistry at another institution, you need to contact Jason Gavenonis ( to complete these forms.

Recommendation Letters

If you are interested in having me write on your behalf for graduate, professional, and/or employment purposes, first ask yourself if I am the best source for these letters.  I am typically happy to write, but in some cases I may not be the best choice to provide a strong positive letter of support. Why is this the case?  If you have taken a lecture course with me, I would be unable to provide a letter that comments on your laboratory skills, which may be important if you are applying to graduate school or positions where lab work is required.  It would be better for you if you were able to ask a recommender who could comment on both your classroom and laboratory skills.  Also, if you are asking me to write on your behalf, I need at a minimum the following information from you:  a sheet with the complete names, addresses, and due dates of the letters you are requesting and the links where they should be sent; your resume; your statement of intent; and a comment on what you believe your strengths and weaknesses are as a student.  In order to write a strong positive letter, I need at least three weeks to complete these letters.  

Note:  If you have a choice as to waive or not waive your right to view the letter, you should know that I only write if you have waived your right in this regard.  If you ask me to write, you have to trust that I will provide a candid, honest, professional opinion on your abilities as a student based on my prior knowledge of you from class and lab.


Research Overview

I use a suite of modern analytical techniques as tools to investigate the behavior and dynamics of trace inorganic and organic chemicals in aquatic ecosystems.  These techniques include chromatographic, spectroscopic, and electrochemical methods in conjunction with mass spectrometry.  My interests have evolved over time, but aquatic chemistry is a central theme that joins together many of my projects:

Metal-ligand complexation reactions in aquatic systems

Metal ions assume variable forms (speciation) in aquatic systems, including a range of oxidation states and complexes. As a consequence, these species exhibit different reactivities, which in turn may influence factors such as their bioavailability and toxicity. My work in this area has focused on the speciation of copper, a micronutrient, in California rice fields, and on the speciation of sulfur in petroleum production effluents (produced water).

Iron speciation in marine systems

Iron is a limiting nutrient in much of the world’s oceans due to its low solubility in seawater. As a consequence, marine organisms have adapted special strategies to acquire iron in low-iron environments. My work in this area has focused on measuring the extent of iron speciation in different oceanic regimes, including the North Atlantic Ocean and the Arabian Sea. In collaboration with others, we also studied how iron chelation affects its bioavailability to marine phytoplankton.

Chemical effects of land-use change in freshwater systems

Urbanization has a profound effect on the aquatic environment and influences local climate, health, water and sediment quality, as well as biota that live in those environments. As forested and/or agricultural land is replaced by impervious surface, the chemicals and transport of those chemicals to urban waterways change. My work in this area has focused on using a new suite of tools including geographic information systems (GIS), principal components analysis (PCA), chemical assemblage data, and correlation analysis to examine how land use change affects stream sediment chemistry in a small urbanizing watershed (Conodoguinet Creek watershed).  

Analysis of plant secondary metabolites

The analysis of plant secondary metabolites is analytically challenging due to their high polarity, multiplicity of functional groups, and fluctuating concentrations that vary throughout the growth cycle.  In this work, carried out in collaboration with Dr. Tom Arnold of the Biology Department, we developed and taught interdisciplinary NSF-funded courses investigating the biochemistry and analysis of plant secondary metabolites to students in over 8 courses.  We continue to study phenolics, glucosinolates, terpenes, alkaloids, and other metabolites using LC-MS and GC-MS methods, and to engage in student-faculty research projects examining these molecules and their breakdown products under conditions of environmental stress (insect attack, low nutrient levels).

External grants awarded (since 1999)  
National Science Foundation CCLI Grant (2010-2013) co-PI with Tom Arnold $199,903
National Science Foundation ADVANCE Program workshop (2010) $188
Pittsburgh Conference Memorial National College Grants Program (2008) $10,000
Hamilton Chemistry Education Grant Program (2007) $2,000
ACS Petroleum Rearch Fund Starter Grant Type GB (2003-2005) $35,000
Society for Analytical Chemists of Pittsburgh (2002-2006) $10,000
Pittsburgh Conference Memorial National College Grants Program (2001) $9,000
Cottrell College Science Grant $35,755
Internal grants awarded (since 1999)  
Dickinson College sabbatical support grant (2017) $1,600
Dickinson College R&D Funds (2017) $1,500
Dickinson College R&D Funds (2014) $1,500
Dickinson College R&D Funds (2012) $1,500
Center for Environmental Sustainability Education (2010) $10,496.20
Mellon Foundation – Central Pennsylvania Consortium (2007) $5,000
Dickinson College R&D Funds Research (2007) $3,828.50
Mellon Foundation – CPC Consortium (2006)  $1,000
Whitaker Grant for Student-Faculty Summer Research (2003) $2,941
HHMI grant for student-faculty research (2002) $10,285.46
Whitaker Grant for Student-Faculty Summer Research (2002) $7,055.02
Whitaker Grant for Student-Faculty Summer Research (2001)  $6,601.03
Whitaker Grant for Student-Faculty Summer Research (2000) $4,598.50
Dana Internship for Student-Faculty Summer Research (2000) $3,600 
Dickinson College R&D Funds (1999)  $1,000

*denotes Dickinson College undergraduate co-author

Witter, AE.  2019.  Quantification of azaarenes, hydroxylated azaarene derivatives, and other polar compounds released in urban runoff from two commercial sealcoat products.  Env Poll, 254, 113103.

Witter, AE and *Nguyen, MH.  2016. Determination of oxygen, nitrogen, and sulfur-containing polycyclic aromatic hydrocarbons (PAHs) in urban stream sediments.  Env Poll, 209, 186 – 196.

Witter AE, and Sak PB.  2014.  Response to O’Reilly’s second letter to the editor on coal-Tar-Based Sealcoated Pavement: A Major PAH Source to Urban Stream Sediments.

Witter AE, and Sak PB.  2014.  Response to letter on Coal-Tar-Based Sealcoated Pavement: A Major PAH Source to Urban Stream Sediments.

Witter AE, *Nguyen MH*, *Baidar S, and Sak PB2014.  Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments.  Env Poll, 185, 59-68.

Witter AE, and Arnold T.  2013. Nature’s Medicine Cabinet: An interdisciplinary course designed to enhance student learning by investigating the ecological roles of natural products. In: Hou, HJM ed. Teaching Bioanalytical Chemistry, Washington, DC: American Chemical Society Symposium Series Books, 1137; 171-186.  

Witter AE.  2011.Water for a Thirsty World: A Liberal Arts Seminar Course Designed for First-Year Non-Science Students.  In: Middlecamp CH, and Jorgensen AD, eds.  Sustainability in the Chemistry Curriculum. Washington, DC: American Chemical Society Symposium Series Books, 1087; 141-158. 

Witter, A.E (2005). You are what you eat: the quantitative determination of butylated hydroxytoluene (BHT) in chewing gum by GC/MS. Journal of Chemical Education, 82(10), 1538 - 1541.

Scott, B.F., MacDonald, R.W., Kannan, K., Fisk, A., Witter, A.E., Yamashita, N., Durham, L., Spencer, C., and D.C.G. Muir. (2005) Trifluoracetate (TFA) Profiles in the Arctic, Atlantic, and Pacific Oceans. Environmental Science and Technology, 39: 6555-6560.

Witter, A.E., *Klinger, D., Fan, X., Lam, M., Mathers, D. and Mabury, S.A. (2002) Quantitative determination of nicotine and cotinine in urine and sputum using a combined SPME-GC/MS method, Journal of Chemical Education, 79, 1257-1260.

Witter, A.E., and Luther G.W. (2002). Spectrophotometric measurement of seawater carbohydrate concentrations in neritic and oceanic waters from the U.S. Middle Atlantic Bight and the Delaware Estuary, Marine Chemistry, 77: 143-156.

Luther, G.W., Rozan, T.F., Witter, A., and Lewis, B. (2001, Sept 28). Metal organic complexation in the marine environment. Geochemical Transactions, Article 9. Retrieved from

Cai, W., Zhao, P., Wang, Y., Theberge, S., Witter, A., and Luther, G.W. (2001). Porewater redox species, pH, and pCO2 in aquatic sediments. In: Electrochemical methods for the environmental analyses of trace element biogeochemistry, Taillefert, M.; Rozan, T., Eds. American Chemical Society Symposium Series Vol. 811; American Chemical Society: Washington, D. C., pp. 188-209.

Witter, A.E., Hutchins, D.A., Butler, A., and Luther, G.W. (2000). Determination of conditional stability constants and kinetic constants for strong model Fe - binding ligands in seawater. Marine Chemistry, 69: 1-17.

Witter, A. E. , Lewis, B.L., and Luther, G.W. (2000). Iron speciation in the Arabian Sea. Deep Sea Research II, 47: 1517-1539.

Hutchins, D.A., Witter, A.E., Butler, A., and Luther, G.W. (1999). Competition among marine phytoplankton for different chelated iron species. Nature, 400: 858-861.

Witter, A.E., and Jones, A.D. (1999). Chemical characterization of organic constituents from sulfide- rich produced water using gas chromatography/mass spectrometry. Environmental Toxicology and Chemistry, 18: 1920-1926.

Witter, A.E. and Luther, G.W. (1998). Variation in Fe-organic complexation with depth in the Northwestern Atlantic Ocean as determined using a kinetic approach. Marine Chemistry, 62: 241-258.

Witter, A.E. and Jones, A.D. (1998). A comparison of methods for speciation of sulfur in a petroleum production effluent. Environmental Toxicology and Chemistry, 17: 2176-2184.

Witter, A.E., Mabury, S.M. and Jones, A.D. (1998). Copper complexation in Northern California rice fields: an investigation using differential pulse anodic and cathodic stripping voltammetry. Science of the Total Environment, 212: 21-37.

Druffel, E. R. D.,Griffin, S. M.,Witter, A. E., Nelson, E., Southon, J.,Kashgarian, M., and Vogel, J. (1995). Gerardia: Bristlecone Pine of the Deep-Sea? Geochim. et Cosmochim Acta , 59: 5031- 5036.

Druffel, E.R.M., Griffin, S.M., and A.E. Witter, 1988. Decade-to-century timescale variability in radiocarbon records from banded corals. Chemical Geology 70: (1-2) 108.

Student-Faculty Research

Collaborative Research (since 1999): *denotes research that earned Departmental Honors 

  • Investigation of microplastics in river sediments along a land-use gradient (Katie Krieger, 2018)
  • A rapid and efficient desulfuration method for glucosinolate analysis using LC-MS (Eryn Nelson, 2017-18)*
  • Comparative metabolite profiling of Solanum lycopersicum leaves in response to biotic and abiotic stressors (Macey Cohen, 2016-17)
  • Characterization of sealcoat weathering at three sites in PA (Zev Greenburg, 2013-2016)*
  • Characterization of organosulfur compounds isolated from mushrooms (Greg Clark and Jonathan Jackson, 2013)
  • Characterization of sealcoat weathering at three sites in PA (Olivia Wilkins, 2012-14)*
  • Profiling PAHs in stream sediments along a land-use gradient (Minh Nyugen, 2009-10)*
  • Electrochemical methods for ascorbate detection in juice (Gerard Mattei, 2009)
  • Chemical characterization of a fluorescent siderophore produced by Pseudomonas fluorescens (Lauren Yura and Laura Romano, 2009; Rebecca Thompson and Kelly Maers, 2008)
  • N-glycan analysis of proteins isolated from marine bacteria (Jeff Rogers, 2007)
  • Source apportionment of PAHs in sediments from the Conodoguinet Creek, PA (Sunil Baidar, 2007)
  • Occurrence of fragrance compounds in sewage sludge (Sunil Baidar, 2007)
  • Chemical characterization of a fluorescent siderophore produced by Pseudomonas fluorescens (Jeff Rogers, Davia Palmieri, Kathleen Aioli, 2006)
  • Developing a protocol for the analysis of N-glycans in bovine fetuin (Sarah Yarnell, 2006)
  • Identifying N-glycans in marine bacteria (Megan Fikse, 2006)
  • Occurrence and speciation of PAHs in LeTort stream sediments using LLE and GC/MS (Matt Stachowiak, 2003)
  • Investigation of triclosan degradation during sewage treatment (Julie Vastine, 2002-03)*
  • Do cyanobacteria produce quorum sensing molecules? (Nick Ferenz, 2002)
  • Effect of nitrogen limitation on EPS production by two species of marine phytoplankton (Denise Sharbaugh, 2002)
  • Ultraviolet-B induced isomerization reaction of phenylpropanoid metabolism intermediates (Dana MacGregor, 2001-02)*
  • Solid-phase microextraction (SPME) GC/MS analysis of tea volatiles (Reena Kanabar, 2001)
  • Fe analysis in seawater using a novel competitive ligand, DHN (Lesley Riggs, 2001)
  • Quantitation of bisphenol A in PA streamwaters (Amy Michael, 2001)
  • Electrochemical Investigations of polysaccharide-metal interactions in aqueous systems (Denise Sharbaugh, 2000)
  • Structural characterization of fluorescent siderophores from Pseudomonas species (Danielle Klinger, 2000)
  • Effect of Fe on carbohydrate production in oceanic cyanobacteria (Dominic Cerminaro, 2000)
  • Isolation of Fluorescent Siderophores from Pseudomonas species (Theresa Urich, 2000)
Selected Presentations

*denotes Dickinson College undergraduate co-authors

*Macey Cohen, Jason Smith, and Witter AE.  August 2017.Comparative metabolite profiling of Solanum lycopersicumleaves in response to biotic and abiotic stressors. Presented at the 254thAmerican Chemical Society Meeting, August 2017, Washington, DC.  Poster presentation by Amy Witter.

*Eryn Nelson and Witter, AE.  August 2017.  Effect of sample preparation on the quantitation of glucosinolates in broccoli and kale cultivars using LC-MS.  Presented at the 254thAmerican Chemical Society Meeting, August 2017, Washington, DC.  Poster presentation by Eryn Nelson.

*Zev Greenberg and Witter, AE. August 2015.  Investigating the chemical composition of sealcoat emulsion in south-central Pennsylvania.Presented at the 250thAmerican Chemical Society Meeting, August 2015, Boston, MA.  Poster presentation by Zev Greenberg.

Witter, AE. August 2015.  Using reflective writing as an instrument to assess student learning in analytical chemistry.  Presented at the 250thAmerican Chemical Society Meeting, August 2015, Boston, MA.  Invited talk presented by Amy Witter.

Witter AE.  August 2014.  Nature’s Medicine Cabinet: An Interdisciplinary Course Designed To Enhance Student Learning by Investigating the Ecological Roles of Natural Products in Plant-Insect Interactions. Presented at the 248thAmerican Chemical Society Meeting, August 2015, San Francisco, CA.  Invited talk presented by Amy Witter.

Witter AE.  March 2014.  Coal-tar-based sealcoated pavement: A major polycyclic aromatic hydrocarbon (PAH) source to urban stream sediments. Presented at the Northeastern section meeting of the Geological Society of America. Invited talk.

Witter AE.  March 2014.  Investigating PAH sources along an urbanizing land-use gradient using chemical, spatial, and statistical tools. Presented at the Department of Environmental Protection, Harrisburg, PA.  Invited talk by Amy Witter

Witter, AE. August 2012.  Using chemical ecology and problem-based learning as a context to    teach undergraduate analytical chemistry.  Presented at the 244thAmerican Chemical    Society Meeting, August 2012, Philadelphia, PA.  Invited talk presented by Amy Witter.

Witter AE.  July 2012.  Nature’s Medicine Cabinet: An Interdisciplinary Course Designed To Enhance Student Learning by Investigating the Ecological Roles of Natural Products in Plant-Insect Interactions. Presented at the 22nd Biennial Conference on Chemical Education, July 29-August 1, 2012, State College, PA.  Invited talk presented by Amy Witter.

*Nguyen MH, and Witter AE.  April 2011. Analysis of PAHs and oxy-PAHs in stream sediments along an increasingly urbanized land use gradient, Conodoguinet Creek Watershed, Cumberland County, PA.  Poster presentation by Minh Nguyen at the 14thAnnual Environmental Chemistry Student Symposium, Penn State University, April 8-9, 2011.

Witter AE.  March 2010.  Water for a thirsty world: a seminar course designed for incoming first-year students. 239thAmerican Chemical Society Meeting, March 20 -23, San Francisco CA.  Invited talk presented by Amy Witter.

Witter AE, *Baidar S, and Sak, PB, August 2009. Distribution of PAHs in sediments along a rural-urban gradient in central PA:  Assessing input sources and transport pathways using compositional analysis, GIS, and multivariate methods. 238thAmerican Chemical Society Meeting, August 17-19, Washington, DC.  Poster presentation by Amy Witter.

*Baidar S, and Witter AE, April 2006. Investigating the occurrence and transport of fragrance compounds in biosolids  from a solid-waste treatment plant, Carlisle, PA.  Presented at the Dickinson College Science Dinner.

*Airola LK, *Palmeri D, *Rodgers J, and Witter AE.April 2006.  Isolation and analysis of a siderophore produced by Pseudomonas fluorescens. Presented at the Dickinson Science Dinner.

Witter AE, *Sharbaugh D, and Hutchins, DA. March 2003. Effects of nitrogen limitation on the composition of phytoplankton-derived dissolved organic matter revealed through carbohydrate analysis. 225th American Chemical Society Meeting, August 23-27, New Orleans, LA.  Poster presentation by Denise Sharbaugh.

*Fan X, Witter AE, *Klinger D, *Lam M, Mathers D,and Mabury SA. August 2002. Quantitative determination of nicotine and cotinine in urine and sputum using a combined SPME-GC/MS method. 224thAmerican Chemical Society Meeting, August 18-21, Boston, MA.  Poster presentation presented by X. Fan.

Witter AE, and Hutchins, DA.  February 2001. Effect of Fe limitation on biomolecule production by marine phytoplankton and cyanobacteria.  Invited talk at 2001 American Society for Limnology and Oceanography, February 12-16, Alburquerque, NM.

Witter AE, *Cerminaro D, *Sharbaugh D, and Hutchins, DA. August 2000.  Effect of Fe limitation on LPS and EPS composition in marine cyanobacteria. 220thAmerican Chemical Society Meeting, August 20-24, Washington, DC. Poster presentation by Amy Witter.



Select service since 1999:

  • Faculty Advisor for Goldwater Fellowship applicants, 2017
  • Faculty Member, President’s Commission for Women, Gender and Sexuality, 2016-17.
  • Biochemistry and Molecular Biology Program Chair, 2017-18
  • Dickinson College Appeals Committee
  • Member of the working group to develop Division III learning goals (January 2013)
  • Member of the Faculty and Personnel Committee, 2007-2010. (Served as Chair, 2009-2010)
  • Chemistry Department Chair; 2006-2007; 2010-2012; 2018-2020
  • Member of Science Executive Committee, 2006 - 2007; 2010-2012
  • Member of Academic Programs and Standards Committee, 2001-2004
  • Member of New Science Building Working Committee, 2001-2003.

Select service in the chemical sciences: 

  • Consultant, Cumberland County Crime Laboratory, Carlisle, PA 2017 - present
  • Served as a chemistry summer camp instructor at Shippensburg University teaching chemistry to students in grades 3-5. (5+ years)
  • Served as an instructor for the Dickinson Connect program during Summer 2015-16.
  • Served as a judge for Carlisle Area School District Science Fair.