High Resolution (HR) Mass Spectrometry

Mass spectrometry is an analytical technique based on two-ion chemistry in the gaseous state. As in other analysis techniques, the basic purpose of a mass spectrometer is to convert the sample into measurable products that indicate the structure of the original molecule. In this case the products formed are gaseous ions whose masses and relative abundances constitute the mass spectrum.

A typical electron impact ionization mass spectrometry (EI-MS) experiment begins with volatilization shown by the action of high baleiro (10-5, 10-6 Torr). Subsequently, a stream of molecules in the gas phase collide with a group of accelerated electrons (20-70 eV). The molecules are thus ionized, giving rise to radical cations that undergo fragmentation. The ions are conducted through a device that selects the fragments they receive or a detector based on the mass/charge ratio they possess.

As described, the technique requires that the sample be placed in the gas phase for further analysis, or that it requires high bearings and high temperatures in the ionization source. This establishes, in principle, a strong limitation in the analysis of two low-volatile composts, of a polar nature, of high molecular weight, or with low thermal stability.

To solve these problems, a series of techniques were developed, including those known as Electrospray Ionization (ESI) and Matrix-Assisted Laser Ionization (MALDI).

The high-resolution mass equipment installed in the service offers a resolution ranging from 7,000 in the case of the smallest TOF to the oldest 6,000,000 in the case of FT-ICR.