With the widespread use of nuclear magnetic resonance (NMR) technology in analytical applications, there is no question that NMR instruments are a commonplace sight in chemistry laboratories around the world. NMR instruments have undergone technological advances over the years, and today’s systems can deliver high-quality spectra with ease while maintaining very high levels of throughput. The benefits of using an NMR over analytical methods such as those of IR and UV-Vis spectroscopies include increased accuracy, sensitivity, reproducibility, and resolution. Perhaps the biggest advantage of NMR spectroscopy is its ability to provide unparalleled structural information.
What Is NMR?
NMR spectroscopy is a powerful analytical technique, which uses the phenomenon of nuclear magnetic resonance to obtain detailed information about the molecular makeup of a sample. NMR spectroscopy is used in many fields, including medicine, biochemistry, chemical engineering, molecular biology, physics, and materials science. Before we discuss the benefits of NMR spectroscopy in biology, we must first explain what NMR is, how it works, and why it is so beneficial for analyzing a wide range of sample types.
NMR spectroscopy uses nuclei that possess a spin, coupling them to a magnetic field. In the presence of a magnetic field, nuclei align with the direction of the field. If a radiofrequency pulse is applied to this system, there is a perturbation of the orientation of nuclei. As the radiofrequency pulse subsides, the nuclei return to their initial states of alignment with the magnetic field, leaving behind a measurable temporal signature.
This signature comes in the form of a decaying curve which is a consequence of relaxation of nuclei from a state of higher energy into a lower energy state.
NMR spectra represent a complex mathematical transformation of the signal of the relaxation of nuclei; namely, a so-called Fourier transformation is applied to the complex decay curve in order to obtain a nicely shaped peak that is easier to “read” for the user. The obtained peaks contain a wealth of information, as their shapes (called “multiplicities”) are indicative of the type of functional group in the molecule, and their intensities are proportional to the concentration of the nuclei, i.e. the concentration of the compound the nuclei belong to.
These technical and conceptual challenges were overcome through improvements in both sample preparation and NMR spectroscopy, making today’s NMR a powerful tool for a wide range of applications.
How Does NMR Spectrosocpy Work?
NMR spectroscopy is a technique for determining the molecular structure of matter. It relies on the magnetic properties of certain atomic nuclei. When placed in a magnetic field, certain nuclei will absorb electromagnetic radiation and subsequently relax, yielding a decaying signal. This signal is then transformed from the time domain into the frequency domain, giving rise to a characteristic NMR signal.
The key parts of an NMR instrument are the probe that contains radiofrequency coils for excitation of the sample nuclei and subsequent signal detection and the supermagnet that surrounds the probe. This magnet is placed into bulky housing and is cooled down to almost absolute zero, by utilizing a combination of liquid nitrogen and liquid helium.The fundamental application of a is to determine the structure of organic molecules or biological molecules by measuring the relaxation of previously excited NMR-active nuclei.
NMR spectroscopy is primarily used in solution state; however, solid-state NMR spectroscopy is a developing field with various applications being perfected recently.
Applications of NMR Chemical Testing
Nuclear magnetic resonance or NMR is a powerful analytical technique used to identify unknown organic and inorganic compounds. NMR is powerful due to its ability to give detailed information about the sample under investigation in a short time. NMR is used to identify unknown compounds, verify the purity and structure of known compounds, and determine the molecular structure of organic and inorganic compounds. The ability to identify molecules and study their chemical bonds is critical in modern-day chemistry and required for a broad range of industrial applications such as organic synthesis and pharmaceuticals.
NMR spectroscopy helps identify and quantify these molecules. The human body contains tens of thousands of different chemical compounds made up of numerous elements; each of which is a key ingredient in a wide range of chemical reactions. By studying the spectrum of these compounds, an NMR instrument can (with the help of a human) determine which compounds are present in the sample. The spectra of compounds give more information about the chemical nature of the reactions taking place within a sample. Finally, an NMR instrument produces data that is often considered the gold standard in quality assurance.
We are used to seeing spectra of the chemical compounds we are trying to understand in the lab. Compound spectra change depending on their three-dimensional structure. This structure confirmed by defining peaks at specific frequency ranges associated with specific atomic configurations and states of matter. NMR instruments are mostly used as tools of organic chemistry. As the instruments became more refined, users got the opportunity to practice biomolecular NMR, applying the method to proteins, and even complex biological mixtures such as human blood, urine, or plant extracts.
Since NMR requires intense, bulky, and energy-consuming equipment, physicists have been looking for more energy-efficient and compact NMR devices. Portable NMR instruments are finding their applications even in the biomedical fields. Due to the non-destructive nature of the method (the sample is preserved), NMR spectroscopy is a candidate for analysing materials and even complex biological tissues, giving it potential in medical diagnostics.
What are the Benefits of Using a High-Resolution NMR Instrument?
High-resolution NMR instruments are extremely useful for a variety of industrial applications. These instruments are capable of providing extremely useful information about complex mixtures of compounds, and they can be used to provide information that is not readily available from other types of analytical instruments, without destroying the sample.
As the number of NMR samples being generated worldwide continues to grow, micro and nanotechnology-based systems that convert NMR signals into digital information have emerged as a fit for a variety of uses. It also has a range of applications, from the examination of tissue samples and environmental samples to chemical metabolite identification. Applications in chemistry, bioanalytical sciences, materials science, and medicine are all represented by the range of NMR instrumentation on the market today.
Having a broad array of analytical capabilities, the technology landscape certainly favors an increasing number of NMR systems that are more capable of analyzing more complex mixtures. These systems are becoming an increasingly popular choice for the industry like types of products become more complex and problems become more challenging.
Conclusion
Nuclear magnetic resonance (NMR) is a technology used to characterize molecular structures and measure certain physical properties of materials, such as their chemical environment or the local magnetic field generated by the material.
NMR spectroscopy is a powerful tool for characterizing molecular structures and measuring certain physical properties of materials, such as their chemical environment or the local magnetic field generated by the material. NMR spectroscopy has proven to be vital to a wide range of applications across a number of industries, and it continues to be one of the most widely used spectroscopic techniques.
