The MacroIMS, manufactured by TSI, is a macroion mobility spectrometer (IMS) for use in analyzing macromolecular structures and characteristics. This instrument is capable of analyzing large molecular structures that would otherwise be too great in mass for traditional mass spectrometers to analyze. Specializing in nanoparticle analysis, this IMS instrument is capable of analyzing molecules ranging in mass from 4 kDa to over 100 MDa. Such particles include anything in a range of mixtures of proteins, biocomplexes, and other macromolecules. Scans of molecular concentrations from 10 pM to 100nM can be returned as quickly as 30 seconds. Such variety and efficiency of scan time makes this instrument well suited for research environments.
The MacroIMS operates through the separation of molecules based on their mobility in a carrier buffer gas. The first step of this process is an ionization source generating gas-phase macroions from the solution phase. This is done via a charge-reduced nanoelectrospray ionization (nanoESI) source, which uses a 25 um ID tip on a silica capillary. Once the molecules are ionized and in the gas phase, they are transferred to the drift cell. It is here that the large molecular weight macromolecules are separated. Under the influence of laminar flow in an electric field, macroions are separated in the annulus of concentric tubes. Adjusting this electric field allows for trajectory changes in molecules, and thus changes separation parameters. A central tube accepts the desired molecules for analysis while preventing others from entering the analytical system.
The MacroIMS is ideal for studying the properties of a variety of macromolecules using the equipped system of Gas-phase Electrophoretic Mobility Macromecule Analysis (GEMMA). Such applications include lipoprotein analysis, virus identification, protein separations, and other organic structural investigations. IMS instruments are ideal for those molecules that have too high a mass for traditional mass spectrometry, but are not large enough for direct light scattering detection. Such instances include the analysis of viruses and protein complexes with proteins as large as 13 MDa. A wide variety of proteins have been visualized with this instrument, making it an invaluable tool for the biotechnology industry, especially for those businesses investigating drug efficacy and the long term stability of immunoglobulins.