1. Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, Texas 79968, United States
2. University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, Texas 79968, United States
3. Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, Connecticut 06504, United States
4. Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 West University Ave., El Paso, Texas 79968, United States