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AMUSE Concept

 

Christina Y. Hampton                                                                                              

Office:  ES&T L2-110

Office Phone:  404-385-4427

E-mail: christina.hampton@gatech.edu

 

Education

2004 - Present     Georgia Institute of Technology, Ph.D. Student, Analytical Chemistry

2003                   Western Washington University, B.S. Chemistry

2001                   Pierce Community College, A.A.S.

 

Honors and Awards

2007 Molecular Biophysics Trainee, Georgia Institute of Technology

2007 Pfizer Graduate Travel Award

2006 Molecular Biophysics Trainee, Georgia Institute of Technology

2006 Richard A. Schaeffer ASMS Travel Award Recipient, Extrel

2006 CETL/BP Outstanding Teaching Assistant Nominee, Georgia Institute of Technology

2005 Outstanding Teaching Assistant in the School of Chemistry & Biochemistry, Georgia Institute of Technology

2004 GAANN Fellowship, Georgia Institute of Technology

2002 Harborstone Credit Union Scholarship, Western Washington University

1999 Outstanding Math Student, Pierce Community College

 

Research Interests

Arrays of Micromachined Ultrasonic Electrospray (AMUSE) Ion Sources

The increasing use of mass spectrometry (MS) in proteomics and metabonomics has generated an urgent need for the development of higher throughput ionization sources which are not subject to the intrinsic limitations of conventional electrospray ionization (ESI), namely, the requirement for high voltages (1-5 kV) to produce liquid atomization, limited dynamic range due to charge transport restrictions and the need to use organic solvent to improve gaseous ion formation. We have shown that the Array of Micromachined UltraSonic Electrosprays (AMUSE), invented and developed by Fedorov and Degertekin [1], and demonstrated on a mass spectrometry system jointly with our group [2], has the potential of overcoming these limitations. The AMUSE decouples the processes of droplet formation and droplet charging by acoustically forcing the ejection of micron-sized droplets from an array with 400 1-5 micron diameter nozzles using an RF potential, while applying a low voltage (100 V) DC potential directly to an aqueous analyte solution. A Venturi device incorporated into the setup increases the linear velocity of the droplet flow causing a corresponding increase in the ion transfer efficiency. Thus far, we have demonstrated the effectiveness of the AMUSE for ionizing standard compounds prepared in acidified aqueous solvent mixtures, even in the absence of DC potentials and our most recent experiments to measure the internal energy deposition of this source using thermometer compounds suggest that ionization by the AMUSE may be softer than that of conventional ESI, producing ions with more controllable salvation shells, supporting our hypothesis that the AMUSE could find widespread applicability in proteomics and suggesting that it may be useful in studies designed to probe protein conformation and macromolecular assemblies.

[1] Fedorov, A. G. and Degertekin, F. L., "Electrospray Systems and Methods", U.S. Patent 7,208,727 (04/24/2007) and U.S. Patent App. 11/594,489 (10/25/2006).

[2] Aderogba, S., et al., Appl. Phys. Lett., 86, 203110-203113 (2005).

AMUSE Ejection Movie (3.8 MB)  This movie shows ejection by the AMUSE.

Venturi-Assisted AMUSE Movie (4.3 MB)  This movie shows the increase in the linear velocity of the ejected droplets produced by the AMUSE as a result of coupling a Venturi device to the AMUSE.

Direct Analysis in Real Time (DART) Screening of Drugs

In many areas of SE Asia, small combination packs of 4-5 drugs ('yaa chud' in Thai) are sold in shops and pharmacies for the treatment of malaria and its associated health effects. These yaa chud are sold without prescription or medical assessment and may contain pharmaceuticals that can effectively treat malaria but more often contain drugs that treat malarial symptoms.  This practice poses a serious health threat as these non-efficacious drugs will not improve the long-term health of the patient, may be contraindicated in pregnancy or childhood, and may increase the spread of drug-resistant malaria. DART is a high-throughput ionization source was used to screen a set of 50 yaa chud bags (182 pills) purchased along the Thai-Burma Border. Only 14% of these yaa chud contained medicine that could have cured malaria while 82% contained medicines that were contraindicated in pregnancy.

 

Click here to see the results of this survey Yaa Chud Compilation.

 

LC/MS-based Metabolism of Calpain Inhibitors

Many acute and chronic neurological disorders such as stroke, spinal cord and head injuries and multiple sclerosis are characterized by severe axonal degeneration. Calpain inhibitors are a class of drugs that prevent axonal degeneration by reducing the level of intracellular calcium and deactivating calpain proteases preventing axonal destruction. We have developed a LC/MS method to quantify the levels of these drugs and their metabolites in serum and tissue samples in an effort to determine the appropriate therapeutic dose as well as to track the distribution of these drugs throughout the body. We are also developing an atmospheric-pressure MALDI method to increase the throughput of these analyses as the limiting factor the LC/MS method is the long time that it takes to prepare and analyze the samples.

Publications

  1. "Comparison of the Internal Energy Deposition of Direct Analysis in Real Time and Electrospray Ionization Time-of-Flight Mass Spectrometry Ionization Techniques", Glenn A. Harris, D. M. Hostetler, Christina. Y. Hampton, F. M. Fernandez, 2009, Accepted.

  2. "A Comprehensive Comparison of Support Vector Machine Classifiers of Ovarian Cancer Metabolomic Data", W. Guan, M. Zhou, Christina Y. Hampton, A. Gray, J. F. McDonald, F. M. Fernandez, BMC Bioinformatics, 2009, In Preparation.

  3. "A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR - implications for therapeutic failure and drug resistance", Sivong Sengaloundeth, Michael D. Green, Facundo M. Fernandez, Ot Manolin, Khamlieng Phommavong, Vongsavanh Insixiengmay, Christina Y. Hampton, Leonard Nyadong, Dallas Mildenhall, Lamphet Khounsaknalath, Lamphone Syhakhang, Paul N. Newton, accepted in Malaria J.

  4. "Liquid Chromatography and Ambient Ionization Time-of-flight Mass Spectrometry for the Analysis of Genuine and Counterfeit Pharmaceuticals", Facundo M. Fernández, Christina Y. Hampton, Leonard Nyadong, Arti Navare, Mark Kwasnik in LC/TOF-MS for Accurate Mass Analysis: Principles and Applications, ed. by I. Ferrer and E.M. Thurman, Wiley: 2009.

  5. "Characterisation of 'Yaa Chud' Medicine on the Thailand-Myanmar Border: Selecting for Drug-resistant Malaria and Threatening Public Health", Paul N. Newton, Christina Y. Hampton, Krystyn Alter-Hall, Thanongsak Teerwarakulpana, Sompol Prakongpan, Ronnatrai Ruangveerayuth, Nicholas J. White, Nicholas P. J. Day, Mabel B. Tudino, Natalia Mancuso, Facundo M. Fernández, Am. J. Trop. Med. Hyg., 2008, 79, 662-669.

  6. "Comparison of Internal Energy Deposition of Venturi-assisted Ionization Sources", Christina Y. Hampton, Catherine J. Silvestri, Thomas P. Forbes, Mark J. Varady, J. Mark Meacham, Andrei G. Fedorov, F. Levent Degertekin, Facundo M. Fernández, J. Am. Soc. Mass Spectrom., 2008, 19(9), 1320-1329.

  7. "A forensic epidemiological investigation into the criminal fake artesunate trade: an international collaboration between police, scientists, and health workers", Paul N Newton, Facundo M. Fernández, Aline Plancon-Lecadre, Dallas Mildenhall, Michael D Green, Li Ziyong, Eva Maria Christophel, Souly Phanouvong, Stephen Howells, Eric MacIntosh, Paul Laurin, Nancy Blum, Christina Y. Hampton, Kevin Faure, Leonard Nyadong, C.W.R. Soong, Budiono Santoso, Wang Zhiguang, John Newton, Kevin Palmer, PLoS Med., 2007, 5(2), e32.

  8. "Analytical Performance of a Venturi-assisted Array of Micromachined UltraSonic Electrosprays (AMUSE) Coupled to Ion Trap Mass Spectrometry for the Analysis of Peptides and Proteins", Christina Y. Hampton, Thomas P. Forbes, Mark J. Varady, J. Mark Meacham, Andrei G. Fedorov, F. Levent Degertekin, Facundo M. Fernández, Anal. Chem., 2007, 79, 8154-8161.

  9. "Characterization of Solid Counterfeit Drug Samples by Desorption Electrospray Ionization and Direct-analysis-in-real-time Coupled to Time-of-flight Mass Spectrometry". Facundo M. Fernández, Robert B. Cody, Michael D. Green, Christina Y. Hampton, Rose McGready, Sivong Sengaloundeth, Nicholas J. White, Paul N. Newton. ChemMedChem, 2006, 1, 702-705.