New article in Wiadomości Chemiczne


Sylwia Jopa, Adam Mames, Tomasz Ratajczyk

Nuclear Magnetic Resonance based methods are currently being widely utilized
in many fields of science, medicine, and industry. The impressive amount of success that has been made with NMR has been possible because an enormous effort has been expended to improve the low level of NMR sensitivity. However, the issue of low NMR sensitivity is still a serious problem, and NMR still cannot be utilized in many important cases where the concentrations of NMR active species are low-this is why the boosting of the NMR signal is currently one of the most important research fields in the NMR area. Here, the problem of low NMR sensitivity is discussed through the presentation of methodologies aimed at increasing NMR sensitivity and their novel applications. First, a short general overview of the NMR and its sensitivity problem will be presented. Having clearly identified the problem, the main technologies that will be utilized for the improvement of NMR sensitivity will be introduced. First, we will concisely, and with appropriate references, present methodologies that can increase NMR sensitivity via the design of novel superconducting magnets, the application of cryotechnology for the design of noiseless probe heads, and other hardware and software approaches. Next, the most promising and powerful method for NMR signal enhancement which is known as hyperpolarization will be discussed.
First, noble gas hyperpolarization and CIDNP will be briefly presented. We will
describe the basic mechanism and applications of these methods. Next, our attention will be paid to the DNP approach, and the origin and applications of the DNP effect will be presented, in particular from the point of view of its utilization in medical diagnostics and material sciences. The most extensive part of our discussion will be devoted to the parahydrogen-based methods, which include hydrogenable Parahydrogen Induced Polarization and Signal Amplification by Reversible Exchange. In the introduction to these methods, the properties of hydrogen molecules, which are the main driving forces of PHIP, will be presented.
The mechanism of the boosting of NMR signals will be presented for hPHIP and
SABRE. The application of these methods will be presented, with the central focus being on their applications in catalysis and medical diagnostics. In the context of medical applications, the hyperpolarization of biorelevant molecules will be presented. Finally, a summary and future prospects for the development of methods of NMR signal enhancement, particularly in the context of hyperpolarization, will be discussed.