1. Group for Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P. O. Box 676, São Carlos, SP, 13565-905, Brazil
2. Facultad Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Santa Rosa, La Pampa, Argentina
3. Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET), Instituto de Ciencias de la Tierra y Ambientales de La Pampa (INCITAP), Santa Rosa, La Pampa, Argentina
4. Department of Chemistry, Clemson University, Clemson, SC 29634, USA
5. Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC 27109, USA