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Charlita Rosal, M.S.
Research Environmental Scientist

Environmental Chemistry, Environmental Sciences, NERL/ORD


Expertise / Research

Individual Research Mission

Impact of Contributions on Scientific/Regulated Community

Conventional sample introduction for GC/MS analysis of organics uses 1-uL sample volume. Sometimes, the level of pollutants is very low that even with sample preconcentration (via extraction of a large volume of sample and condensation of extract down to less than 1 mL), detection is not possible. Increasing analyte load by injecting large volume of extract (e.g., 20 uL) enhances sensitivity to compensate for the limited detection sensitivity of mass spectrometer. Large-volume injection (LVI)-GC/MS is useful in exposure assessment of sensitive ecosystems and baseline monitoring of pristine environments.

Because of the different levels of toxicity each species exhibits, elemental speciation is critical in assessing risk for a more sensible and cost-effective clean-up goals. CE-ICP/MS is a technique that provides excellent resolution and sensitivity while utilizing a very small-size sample volume (nL) for analysis so that sample collection and transport are minimized, thus saving cost and time. Most of all, the technique is “green” (generating very low amounts of wastes) which responds to EPA’s mission of pollution prevention.

Professional Experience January 1997 - present:

Environmental Research Scientist, U.S. EPA, National Exposure Research Laboratory, Environmental Sciences Division (USEPA/NERL/ESD), Environmental Chemistry Branch, Las Vegas, Nevada.

June 1991 - January 1997: Environmental Scientist, USEPA/NERL/ESD, Characterization and Monitoring Branch.

November 1980 - October 1982: Science Research Specialist I, Phil. Atomic Energy Commission, Phil.

November 1979 - November 1980: Nuclear Technician, Phil. Atomic Energy Commission, Phil.

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Bradford, D. F., E. M. Heithmar, N. G. Tallent-HalsellL, G. Momplaisir, C. G. Rosal, K. E. Varner, M. S. Nash, and L. A. Riddick. Temporal Patterns and Sources of Atmospherically Deposited Pesticides in Alpine Lakes of the Sierra Nevada, California , USA. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 44(10):4609-4614, (2010). Published 05/24/2010.

Rosal, C., Riddick, L., Momplaisir, G-M., Heithmar, E., Varner, K.. Ferguson, P. Pulsed-Splitless and Large-Volume Injection in Capillary Gas Chromatography Mass Spectrometry for the Determination of Ultra-trace level Pesticide Residues from Lake Waters [PDF, 1 pp., 655 KB], presented at the National Environmental Monitoring Conference, Washington, D.C., July 22, 2003.

Rosal, C., Riddick, L., Heithmar, E., Momplaisir, G-M., Varner, K., Ferguson, P., Bradford, D., and Tallent-Halsell, N. Analysis of Low-Level Pesticides from High-Elevation Lake Waters by Large-Volume Injection GC/MS, presented at PITTCON 2003, Orlando, FL, March 13, 2003.

Rosal, C.G., Momplaisir, G-M., and Heithmar, E.M. Determination of Roxarsone, an Arsenic Animal-Feed Additive, and its Transformation Products in Chicken Manure by CE-ICPMS and µHPLC-ICPMS [PDF, 1 pp., 189 KB], presented at the 2002 Winter Conference on Plasma Spectrochemistry, Scottsdale, AZ, January 8, 2002.

Rosal, C.G., Momplaisir, G-M., and Heithmar, E.M. National Park Aquatic Samples: Multielements by Inductively Coupled Plasma Mass Spectrometry [PDF, 1 pp., 891 KB], presented at the 2000 Winter Conference on Plasma Spectrochemistry, Fort Lauderdale, FL, January 14, 2000.

Rosal, C.G. and Dupont, R.R. Subsurface Monitoring for Assessing In Situ Biocontainment of Petroleum Contaminated Ground-Water Plumes, presented at the Technical Support Project Meeting, Las Vegas, NV, 1995.

Rosal, C.G. Polonium-210 in Lake Mead Fish, presented at the 1992 Pacific Conference on Chemistry and Spectroscopy, Foster City, CA, October 21, 1992


Borden, R.C., Goin, R.T., Kao, C., and Rosal, C.G. 1996. "Enhanced Bioremediation of BTEX Using Immobilized Nutrients: Field Demonstration and Monitoring," EPA/600/R-96/145.

Pohlmann, K.F., Icopini, G.A., and Rosal, C.G. 1995. "Evaluation of Field-Filtration Variables for Representative Samples of Trace Metals is Ground Water. Ground Water Sampling - A Workshop Summary," EPA/600/R-94/205.

Rosal, C.G. 1995. "EMSL-LV UST Monitoring Research Projects. Underground Tank Technology Update," vol. 9, no.1.

Pohlmann, K.F., Icopini, G.A., McArthur, R.D. and Rosal, C.G. 1994. "Evaluation of Sampling and Field-Filtration Methods for the Analysis of Trace Metals," EPA/600/R-94/119.


GC-MSD ChemStation Data Analysis and Reporting, Anaheim, CA, December 18-29, 2001.

5973 GC-MSD Troubleshooting and Maintenance, November 27-29, 2001.

Chemical Mechanisms in Toxicology, April 1999.

Toxicology: Principles and Applications, April 1999.

Sample Introduction for ICP/AES and ICP/MS, March 7, 1999.

Introduction to Capillary Electrophoresis and Troubleshooting CE Methods and Systems, August 18-19, 1999.

LC/MS: Fundamentals and Applications, ACS short course,

Principles of Ground Water Hydrology, Nashville, TN, July 16-18, 1991.

Interregional Training Course on the Preparation and Control of Radiopharmaceuticals, sponsored by the International Atomic Energy Agency, Athens, Greece, November 1-26, 1982.


Environmental Sciences | Research & Development
National Exposure Research Laboratory
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