Mass spectrometry was taught to measure individual molecules

Dutch physicists have managed to create a mass spectrometer which can directly measure the mass of individual molecules. Earlier mass spectrometers worked with molecular ensembles, which led to a number of difficulties in the measurement of large molecules: the overlap of the spectrum and more complexity in the measurement of the charge of ionized molecules. The new method allows to analyze each molecule separately and avoid these problems. Soon the invention will be widely distributed in gene therapy, write the scientists in the journal Nature Methods.

The trajectory of a neutral particle (atom or molecule) is not affected by electric and magnetic fields. But if you take away a few electrons, the particle will acquire a charge and its trajectory in the field will start to bend. The nature of the bending of the trajectory in the field will be determined by the mass of the particle and its charge. Physicists measure the deflection from a straight path, from which it is easy to obtain the ratio of the mass of the particle to its charge. Hence — if you know the charge — physics find the mass of a molecule or atom. This technique is called mass spectrometry.

In turn, mass spectrometry is divided into many variants. Almost all of them are based on finding the mass of a molecule and its constituent units from the schedule of readings about the relationship of mass-to-charge. The problem is that for large molecules (e.g. protein) to obtain data on the charge after ionization is not so simple. Scientists analyze the successive peaks of the measurement of a variety of molecules to find data about the charge and only then determine the mass of the molecule.

Moreover, the minor structural changes of the molecules lead to the wide variation in the spectrum of masses and provoke unwanted overlap that negatively affect measurement accuracy. The solution to this problem is the measurement of each molecule separately.

A group of physicists led by Tobias Werner (Tobias Wörner P.), Utrecht University solved this problem. Scientists have demonstrated a single-particle mass spectrometry with the detection of charge on the basis orbitrap electrode around which the ions revolve. Orbitrap is not a new device, but was used only for many-particle measurements. In the new work, the molecules reach orbitrap one.

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