Director, Mass Spectrometry Facility
Senior Research Scientist, Senior Researchers and Specialists
Mehdi Moini

Contact Information

Office
WEL 1.408B
Office Phone
471-7344
Fax
471-1420

Education

PhD, Michigan State University (1985); Postdoctorate, University of Florida (1986-7)

Bioanalytical Mass Spectrometry and Instrumentation

My area of research is mass spectrometry with emphasis on the development of new instrumentation for rapid and sensitive proteomics and metabolomics. Our present active areas of research include:

Development of Capillary Electrophoresis to Mass Spectrometry Interface and Its Application to High Throughput Proteomics and Metabolomics

In this area we have introduced three novel CE to MS interfaces. The most recent one, the "porous junction" design, enables us to interface very narrow capillaries (50 proteins in ~1/2 hour. In the area of metabolomics, we have introduced a sensitive CE/ESI-MS technique for the analysis of small molecules such as amino acids and their D/L enantiomers in one run. Recent developments in this area include capillary isoelectric focusing to mass spectrometry interfacing using both ESI and MALDI. Currently, the latter techniques are being evaluated using standard protein mixtures.

Enhanced Sensitivity of Detection under ESI-MS through the Use of Complexation Agents

Recently, we introduced a technique to enhance the sensitivity of detection of small molecules under ESI. At this time, we have applied this technique to the analysis of compounds containing a primary amine. The key finding of this study is detection of primary amines (including several neurotransmitters), amino acids, and their D/L enantiomers in one run at attomole levels through the use of a complexation reagent (18-crown-6-tetracarboxylic acid) and using only ~ 1 nL of sample. The technique uses underivatized compounds in conjunction with underivatized CE capillaries, thereby, significantly reduces cost and analysis time.

Development of Multi-inlet Mass Spectrometry for High Throughput Proteomics

In this area we have developed a patented design in which a mass spectrometer can have multiple nozzles that can be interfaced to multiple HPLCs or CEs. At this time, we have interfaced up to eight HPLCs or 8 CE capillaries to one TOF-MS and have simultaneously analyzed 8 protein digests with high mass accuracy in less than an hour. This design is especially important in proteomics and metabolomics, when several protein digests are analyzed simultaneously, significantly reducing the analysis time.

Development of Ion-Trap Ion-Mobility Time-of-Flight Mass Spectrometry

Recently, we have successfully analyzed the sub-cellular proteomics of the ribosomal proteins of E. coli (~55 proteins) in ~1/2 hour using CE/ESI-MS. However, the analysis of ~1000 proteins with this technique is too complicated, and, therefore, we are in the process of developing a new 2-D technique based on the use of CE in conjunction with ion mobility time-of-flight MS. The technique would be used to analyze more complex proteins and provide information regarding 3 dimensional structures of proteins.

Representative Publications

  • "Capillary Electrophoresis to Mass Spectrometry Interface Using a Porous Junction" Anal. Chem. 75 (2003): 2188-2191.

  • "Capillary Electrophoresis Mass Spectrometry and its Application to the Analysis of Biological Mixtures" Anal. Bioanal. Chem. 373 (2002): 466-480.

  • "Analysis of Carbonic Anhydrase in Human Red Blood Cells Using Capillary Electrophoresis Electrospray Ionization Mass Spectrometry" Anal. Chem. 74 (2002): 3772-3776.

  • "Analysis of Underivatized Amino Acid Mixtures using HPLC/ Dual Oscillating Nebulizer Atmospheric Pressure Microwave Induced Plasma Ionization-Mass Spectrometry." J. Am. Soc. Mass Spectrom. 12 (2001): 117-122.

  • "Development of Multi-ESI-sprayer, Multi-atmospheric-pressure-inlet Mass Spectrometry and its Application to Accurate Mass Measurement Using Time-of-flight Mass Spectrometry" Anal. Chem. 72 (2000): 20 & 885.

  • "CE/ESI-MS Analysis of Underivatized D/L-Amino Acids and Several Small Neurotransmitters at Attomole Levels Through the use of 18-Crown-6-Tetracarboxylic Acid as a Complexation Reagent/ Back Ground Electrolyte" Anal. Chem. (1999)