Comprehensive Multiphase NMR Spectroscopy of Intact ¹³C-Labeled Seeds

Abstract

Seeds are complex entities composed of liquids, gels, and solids. NMR spectroscopy is a powerful tool for studying molecular structure but has evolved into two fields, solution and solid state. Comprehensive multiphase (CMP) NMR spectroscopy is capable of liquid-, gel-, and solid-state experiments for studying intact samples where all organic components are studied and differentiated in situ. Herein, intact (13)C-labeled seeds were studied by a variety of 1D/2D (1)H/(13)C experiments. In the mobile phase, an assortment of metabolites in a single (13)C-labeled wheat seed were identified; the gel phase was dominated by triacylglycerides; the semisolid phase was composed largely of carbohydrate biopolymers, and the solid phase was greatly influenced by starchy endosperm signals. Subsequently, the seeds were compared and relative similarities and differences between seed types discussed. This study represents the first application of CMP-NMR to food chemistry and demonstrates its general utility and feasibility for studying intact heterogeneous samples.

In vivo comprehensive multiphase NMR

“…13 C NMR is a simple and effective approach to obtain metabolic information in vivo and does not require water suppression. In this case, as only low‐power decoupling was used, the experiment will bias 13 C attached to protons with relatively narrow line shape (i.e., liquids and gels) and discriminate against true solids . If absolute quantification is required with each phase being represented equally, then the recently published approach of stepped decoupling, specifically developed for 13 C quantification in multiphase samples, should be employed …”

“…In many ways, CMP NMR can be thought of as changing NMR technology to match natural samples, rather than changing the sample to match a specific NMR technique. CMP NMR has permitted the study of structural interactions and processes in unaltered heterogeneous samples, including soil, swelling of rubber by biofuels, intact plants, and to follow biological processes (seed growth) …”

Comprehensive multiphase NMR spectroscopy: A new analytical method to study the effect of biodiesel blends on the structure of commercial rubbers

“…Therefore this probe permits to study all phases within sample in their native state, without any physical separation. This approach has enabled the studies of chemical composition and the interactions in complex multiphase samples [29]. Typically, one-dimensional NMR [30,31] as well as measurements of relaxation rates [32,33], residual dipolar couplings [34][35][36], and other techniques are employed to understand the structure and aging of elastomers.…”

Advancements in waste water characterization through NMR spectroscopy: review

“…For example, high-resolution magic angle spinning (HR-MAS) [21][22][23][24] and, more recently, comprehensive multiphase probes (CMPs) [25] permitted the use of a single hybrid NMR probe to obtain solution-state, gel-state (HR-MAS) and solidstate experiments that are available today. [26,27] This technology allowed for the study of both structures and interactions as well as between phases in the native state to fully understand unaltered complex systems. Thus, the ability of NMR to provide information on the molecular scale for analytes of different physical states, while employing little or no pretreatment, makes it highly suitable for environmental studies.…”