Progress in low-field benchtop NMR spectroscopy in chemical and biochemical analysis

Abstract

The employment of spectroscopically-resolved NMR techniques as analytical probes have previously been both prohibitively expensive and logistically challenging in view of the large sizes of high-field facilities. However, with recent advances in the miniaturisation of magnetic resonance technology, low-field, cryogen-free "benchtop" NMR instruments are seeing wider use. Indeed, these miniaturised spectrometers are utilised in areas ranging from food and agricultural analyses, through to human biofluid assays and disease monitoring. Therefore, it is both intrinsically timely and important to highlight current applications of this analytical strategy, and also provide an outlook for the future, where this approach may be applied to a wider range of analytical problems, both qualitatively and quantitatively.

Chemical Constituents with GNMT-Promoter-Enhancing and NRF2-Reduction Activities from Taiwan Agarwood Excoecaria formosana

“…Comparing with (24R) 24-ethyl-7β-hydroperoxy-cholest-5-en-3β-ol and (24R) 24-ethyl-7α-hydroperoxy-cholest-5en-3β-ol [27], the chemical shift of C-6 was (δ C 126.0) in 7-β-stereoisomer, while the chemical shift of C-6 was (δ C 119.9) in 7-α-stereoisomer. Thus, the structure of Compound 1 was further confirmed by COSY and ROESY data ( 33.9 23 25.9 24 45.8 25 29.3 26 19.8 0.81 (d, 6.2) 27 19.0 0.82 (d, 6.2) 28 23.1 29 12.0 0.88 (t, 7.2)…”

“…From a biosynthetic point of view, the monomeric lignin precursors (6)(7)(8)(9)(10)(11), coumarins (17)(18)(19), and the condensation of lignin with coumarins-coumarinolignans (20)(21)(22)(23)(24)(25) were successively isolated from this plant. Therefore, we regarded Compounds 2 and 3 as natural plant constituents.…”

Benchtop Low-Frequency 60 MHz NMR Analysis of Urine: A Comparative Metabolomics Investigation

“…Metabolomics is a powerful approach which, in the space of a few decades, has developed considerably, and HF NMR analysis is one of the most commonly applied techniques to perform metabolomics studies. However, despite adoption in several domains, the application of LF spectrometers for this purpose remains limited [8,11,13]. Here, we have reported metabolomics analysis comparisons between the 1 H NMR profiles of T2D and control participant urine samples acquired by both high-and low-frequency NMR techniques.…”

“…However, HF NMR analysis also presents a number of disadvantages, such as cost, size, and transportation limitations, and often the requirement for specialist technical staff for instrumental operation. Moreover, the size of such high-resolution NMR facilities limits their accessibility to many researchers, and therefore precludes regular use outside of university-based NMR-dedicated laboratories, along with those in large industrial centres.Low-frequency (LF) applications of NMR have previously been explored in some detail [8][9][10], and the future of NMR-based metabolomics has also been recently discussed, with an emphasis on this approach providing a convincing solution for metabolic fingerprinting at 'point-of-care' sites or prospectively, even for personal use [11][12][13]. Moreover, LF 1 H NMR applications have recently been shown to distinguish between control and type 2 diabetic (T2D) participants, with potential use for point-of-care applications in a metabolomics study using a near-portable benchtop NMR spectrometer as a novel bioanalytical tool [11].…”

Examination of Prognostic Factors Affecting Long-Term Survival of Patients with Stage 3/4 Gallbladder Cancer without Distant Metastasis

“…First, this single institutional retrospective study extended to three decades, during which the therapy for GBC underwent numerous changes. These changes included differences in operative approaches, diagnostic imaging [32], techniques of perioperative management, and advances in adjuvant therapy and chemotherapy (such as various chemotherapy agents), infection control, use of antimycobacterial agents, nutritional management, and progress in strategies for biliary drainage. Second, treatment strategies varied depending on the era, as mentioned in the surgical policy section in the Methods.…”