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Department of Environmental Health

Center for Environmental Genetics

 Analytical & Mass Spectrometry of Small Molecules

Analytical and mass spectrometry services fall under the umbrella of the University of Cincinnati / Agilent Technologies Metallomics Center of the Americas. Services include a variety of analyses, including metals, particular metal forms, and other substances, such as environmental contaminants and metabolites. Projects that require as-yet-undeveloped methods will require particular interactions with the PIs for the different sample types, including tissues, body fluids, cell inoculants, cells, and cellular compartments.

The Metallomics Core provides sample service, methods development for metal speciation studies, and other applications not involving metals and training for students, postdoctoral fellows, and other technical personnel as necessary and desirable for the various projects. Both state-of-the-art elemental and molecular mass spectrometric instrumentation are available for a full range of analyses. The training component trains users on ICP-MS, LC-ICP-MS, LC-UV, LC-CHIP IonTrap MS, and GC-ICP-MS to the point that they are able to run samples and interpret results on their own with appropriate protocols.

The Center also trains in a variety of sample-preparation methods, such as total digestion and various extraction techniques (with a green chemistry focus), solid-phase extractions (SPE; solid-phase micro-extractions, stir-bar absorptive extractions, Tenax columns, microcolumn ion-exchange, or reversed-phase sample preparations), and state-of-the-art microwave extractions via the CEM-Explorer 24 computer-controlled multi-sample unit.

Services Provided by Analytical and Mass Spectrometry of Metals and Small-to-Large Molecules

Total metal analyses, either single or multiple metals. Metals include metalloids plus halogens, S and P. During the past years, metals have included As and Cr but can extend to Pb, Mn, Hg. and others. Samples may be solid, liquid, and gaseous and prepared or not by the Core.

Metal/metalloid speciation analyses. The Core has developed several As, Cr, Sn, Se, and nonmetal speciation methods that can be applied to any type of samples. Other metals such as Hg can also be analyzed to determine speciation and total amounts. The Core will handle anything from the intact sample through preparation, separation, detection, and interpretation, depending on PI needs. The Core uses the full complement of high-performance liquid chromatography methods (LC) with various detectors. It can also do GC with FID, quad-MS, TOF-MS (exact mass capabilities), and ICP-MS detectors. Various sample types can be accommodated: tissues, body fluids, and cultured cells.

 Any work done in conjunction with the Mass Spectrometry core follows Center protocols and charge rates.

Organic analyses for a wide variety of metabolites, peptides, and metalloproteins. With mass spectrometric methods, metal, metalloid, P, S, Br, or I functionality, quantitative analyses with speciation can be detected at levels below parts per million.

Metal proteomics studies involving metals associated with proteins or those more tightly bound. The Core is be able to utilize 1-D or 2-D gels to determine metal or element functionality for the 200 or so spots typical of a 2-D gel. Analysis will focus on particular heteroatoms to screen for molecular mass spectrometric identification. This may be helpful for acquiring quantitative information in, for example, numbers of phosphorylation sites and location. Spots of interest can then be taken to MALDI and/or ESI-MS, which follows a general protein identification scheme for which the initial ICP-MS has lessened the complexity.

Typical turn-around time: 1 to 2 weeks from reception of order to delivery of the report. In critical situations, the Core has been able to expedite service. The primary cause of delay is instrument down time; however, the Core has service contracts on the Agilent instrumentation, so these delays are typically only a few days.