Ultra-High Mass Resolution MALDI-TOFMS System

The topographic effect of the matrix crystal leads to a difference in flight start position for the ions, resulting in a difference in flight time. In the conventional ion optical system, this time difference degrades the mass resolving power and also the mass accuracy obtained with external mass calibration. With its extended flight distance, the JMS-S3000 reduces this effect to the minimum and achieves highly reproducible mass resolving power and high mass accuracy with an external mass calibration. High mass-resolution and mass accuracy can be maintained for imaging analysis of a biological specimen in which a large number of mass spectra are acquired across a large area and the specimen surface is likely to be uneven.

The SpiralTOF™-plus 2.0 has realized a wide dynamic range by greatly improving the detection system. This makes it possible to simultaneously detect peaks with ion intensity differences of about 4 orders of magnitude. Also, the analysis of trace components has become easy in mass spectrometry imaging measurements, in addition to the conventional bulk sample measurements. Below is the measurement example of a mixture of polyethylene oxide and polypropylene oxide in the ratio of 1,000:1. In the case of polymer analysis, when combined with the Kendrick Mass Defect (KMD) analysis, it is possible to analyze trace components that are otherwise difficult to detect.

Industrial polymeric materials based on mixtures of polymers with different end groups or copolymers contain a wide variety of compounds. It is necessary to detect all the components in order to grasp the whole picture, which requires ultra-high mass resolution in a wide mass range. In addition, it is important to detect not only the base material but also trace components because multiple types of polymers and trace additives are blended for higher functionality.

MALDI MS imaging was initially developed to focus on high molecular weight compounds such as proteins and peptides. However, with the expanding applications of MALDI MS imaging, the interests have shifted to include smaller molecules such as lipids, pharmaceuticals, and pharmaceutical metabolites. Conventional MALDI - reflectron TOFMS has difficulty discerning small molecule signals from those of matrix. In the case of MALDI MS imaging, signals from unwanted molecules on the specimen surface will often interfere with signals from the target analytes. High selectivity by means of high mass-resolving power is essential for obtaining reliable target analyte spatial distributions. It is also important to maintain high mass-resolution and mass-accuracy for a long time even when measuring a sample surface with a large area and non-uniformity. SpiralTOF™-plus 2.0 is the only MALDI-TOFMS that meets imaging requirements with ultra-high mass-resolution and long flight distance to minimize loss of mass resolution due to sample surface non-uniformity. In addition, it also supports high-speed mass imaging analysis.

PE: Phosphatidyl ethanolamine, PC: Phosphatidyl Choline, GalCer: Galactosylceramide

Mass spectrometry imaging can be applied to polymers. Two spots are prepared by adding two antioxidants - Irgafos 168 (BASF) and Irganox 1010 (BASF) - to polymethylmethacrylate (PMMA). The ultraviolet irradiation was performed to the right spot only and its degradation was visualized by using mass spectrometry imaging. For polymers, it is possible to visualize the quantitative change in both polymers and additives. It is also possible to capture the changes in the average molecular weight and polydispersity.

For the detailed analysis of a protein, not only the intact protein but also enzymatic digest of the protein can be analyzed. Peptide mass fingerprinting allows identification of a protein.

* 3D-structure of RCSB PDB (www.rcsb.org) ID 1IGY (Harris, L.J., et al. (1998) J.Mol.Biol.

Previously, MALDI-TOFMS systems were not suitable for the analysis of small molecules as matrix-derived peaks and continuous chemical noise interfere with the signal from analyte molecules. The SpiralTOF ion optics have solved these problems.