Dr. Gerardo Gamez
Title: Assistant Professor
Education: Ph.D., Indiana University, 2006, Postdoctoral Study, Swiss Federal Institute of Technology
(ETH) Zurich, 2006-2009
Research Area: Analytical Chemistry
Office: Chemistry 328-B
Webpage: Research Group
Principal Research Interests
The main focus of the Gamez group is to develop novel techniques to overcome challenges
encountered in the analysis of relevant materials and biological systems. One area
in which we are interested is chemical imaging: the ability to obtain spatially resolved
chemical landscapes is critical for understanding the mechanisms in biological systems
and guiding the development of novel materials. One of the challenges faced in chemical
imaging is obtaining elemental maps of large areas in a fast manner such that it becomes
practical for routine analysis. We are overcoming this challenge by developing a glow
discharge optical emission spectroscopy technique (i). Another challenge in chemical
imaging is that typical analysis techniques that provide high spatial resolution do
not give chemically-rich information, and vice versa. We are overcoming this challenge
by coupling near-field spectroscopies with scanning force microscopy (ii). Another
area in which we are interested is mass spectrometry: the ability to obtain elemental,
structural, molecular, and isotopic information is also critical for many relevant
samples. One of the challenges in mass spectrometry is the sample preparation that
allows the introduction of solid samples into the mass spectrometer and is typically
the bottleneck in the analysis. We are overcoming this challenge by developing ambient
ionization techniques (iii).
- Chemical Imaging
- Optical Spectroscopy
- Mass Spectrometry
1. Glow discharge optical emission spectroscopy (GDOES) is a cathodic sputtering technique
that has gained wide interest because it allows quantitative elemental depth profiling
from surfaces (with nm resolution) with high sample throughput. However, the lateral
resolution in GDOES is typically limited by the sputtered area (mm). Very recent developments
showed the possibility to obtain laterally resolved information from within the sputtered
area by operating the GD in pulsed power mode, which opened the possibility to map
large areas (100 cm2) simultaneously in a matter of seconds. This research avenue
will serve to enable fast chemical imaging and improve the understanding of glow discharge
2. Areas of research where nanoscales are encountered require analysis techniques to
aid in their development. The problem is that typically techniques with high spatial
resolution do not give rich chemical information, and vice versa. In this research
avenue near-field laser sampling will be coupled to optical and mass spectrometries
to develop techniques that yields rich chemical information with nanoscale spatial
resolution. Also, an improved understanding of laser-material interactions will be
3. Ambient ionization mass spectrometry has gone through a spectacular growth in a short
amount of time because they enable desorption, extraction, ionization with little
to no sample preparation. There has been a multitude of techniques developed along
with a myriad of proof-of-principle applications. Although application development
is still growing, there is a need to further understand the fundamental processes
and overcome quantitation problems. This research avenue will focus on studying the
mechanisms and matrix effects encountered in ambient ionization while developing new
applications, such as monitoring medication metabolites.
Members in the group get experience in several disciplines outside of chemistry,
including biology and materials science. The multi-component character of the research
projects allows the early-stage and experienced researchers to obtain and hone skills
in instrument development (from design to implementation), method development, and
fundamental experiment design.
- "Ultrafast Elemental Mapping of Materials Combinatorial Libraries and High-throughput
Screening Samples via Pulsed Glow Discharge Optical Emission Spectroscopy"., Gamez, G.; Mohanty, G.; Michler, J., J. Anal. Atom. Spectrom., 2013, accepted.
- "Push-broom Hyperspectral Imaging for Elemental Mapping with Glow Discharge Optical
Emission Spectrometry"., Gamez, G; Frey, D.; Michler, J.; J. Anal. Atom. Spectrom., 2012, 27 (50-55).
- "Glow Discharge Techniques in the Chemical Analysis of Photovoltaic Materials"., Schmitt, S.W.; Venzago, C.; Hoffmann, B.; Sivakov, V.; Hofmann, T.; Christiansen,
S.H.; Michler, J.; Gamez, G.Prog. Photovoltaics.Res. Appl., 2012, DOI: 10.1002/pip.2264.
- "Real-time, In Vivo Monitoring and Pharmacokinetics of Valproic Acid via a Novel Biomarker
in Exhaled Breath"., Gamez, G.; Zhu, L.; Disko, A.; Chen, H.; Azov, V.; Chingin, K.; Krämer, G.; Zenobi,
R. Chem. Comm., 2011, 47 (4884-4886).
- "Material Ejection and Redeposition Following Atmospheric Pressure Near-Field Laser
Ablation on Molecular Solids"., Zhu, L.; Gamez, G.; Schmitz, T. A.; Krumeich, F.; Zenobi, R. Anal. Bioanal. Chem., 2010, 396 (163-172).
- "What Can We Learn From Ambient Ionization Techniques?", Chen, H.; Gamez, G.; Zenobi, R. J. Am. Soc. Mass. Spectr., 2009, 20 (1947-1963).
- "Rapid Detection of Melamine in Untreated Milk and Wheat Gluten by Ultrasound-assisted
Extractive Electrospray Mass Spectrometry (EESI-MS)"., Zhu, L.; Gamez, G.; Chen, H.; Chingin, K.; Zenobi, R. Chem. Commun., 2009, 5 (559-561).
- "Towards Nanoscale Molecular Analysis at Atmospheric Pressure by a Near-Field Laser
Ablation Ion Trap/Time-of-Filght Mass Spectrometer"., Schmitz, T.; Gamez, G.; Setz, P. D.; Zhu, L.; Zenobi, R. Anal. Chem., 2008, 80 (6537-6544).
- "Photoelectron Emission as an Alternative Electron Impact Ionization Source for Ion
Trap Mass Spectrometry"., Gamez, G.; Zhu, L.; Schmitz, T.; Zenobi, R. Anal. Chem., 2008, 80 (6791-6795).
- "Atmospheric-Pressure Chemical Ionization Source. Part I: Ionization of Compounds
in the Gas Phase"., Andrade, F. J.; Shelley, J.; Wetzel, W. C.; Webb, M. R.; Gamez, G.; Ray, S. J.;
Hieftje, G. M. Anal. Chem., 2008, 80 (2646-2653).