Microflow NMR:  Concepts and Capabilities

Olson, Dean L.; Norcross, James A.; O'Neil–Johnson, Mark; Molitor, P. F.; Detlefsen, David J.; Wilson, and Aaron G.; Peck, Timothy L.

doi:10.1021/ac035426l

Cited by 130 publications

(120 citation statements)

References 22 publications

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“…Because a large number of analyses were conducted, a rapid UPLC method was hydrogens in molecular formula) suggested further oxidation of the JA moiety. However, the complete characterization of both compounds had to rely on CapNMR (25), and thus their isolation from larger quantities of wounded plant material (500 g) was needed.…”

Section: Profiling Of Oxygenated Fatty Acids By Uplc-tof-msmentioning

confidence: 99%

Spatial and Temporal Dynamics of Jasmonate Synthesis and Accumulation in Arabidopsis in Response to Wounding

Glauser

Grata

Dubugnon

et al. 2008

Journal of Biological Chemistry

310

290

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A new metabolite profiling approach combined with an ultrarapid sample preparation procedure was used to study the temporal and spatial dynamics of the wound-induced accumulation of jasmonic acid (JA) and its oxygenated derivatives in Arabidopsis thaliana. In addition to well known jasmonates, including hydroxyjasmonates (HOJAs), jasmonoyl-isoleucine (JA-Ile), and its 12-hydroxy derivative (12-HOJA-Ile), a new wound-induced dicarboxyjasmonate, 12-carboxyjasmonoyl-L-isoleucine (12-HOOCJA-Ile) was discovered. HOJAs and 12-HOOCJA-Ile were enriched in the midveins of wounded leaves, strongly differentiating them from the other jasmonate metabolites studied. The polarity of these oxylipins at physiological pH correlated with their appearance in midveins. When the time points of accumulation of different jasmonates were determined, JA levels were found to increase within 2-5 min of wounding. Remarkably, these changes occurred throughout the plant and were not restricted to wounded leaves. The speed of the stimulus leading to JA accumulation in leaves distal to a wound is at least 3 cm/min. The data give new insights into the spatial and temporal accumulation of jasmonates and have implications in the understanding of long-distance wound signaling in plants.

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Section: Profiling Of Oxygenated Fatty Acids By Uplc-tof-msmentioning

confidence: 99%

Spatial and Temporal Dynamics of Jasmonate Synthesis and Accumulation in Arabidopsis in Response to Wounding

Glauser

Grata

Dubugnon

et al. 2008

Journal of Biological Chemistry

310

290

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“…The current SNR of this probe is diminished compared with the commercially available small volume microcoil probes (3,25,38) or those previously constructed in our laboratory (10,13,16). We believe that a significant loss of signal results from the use of the transmission line element.…”

Section: -Ll Nmr Probementioning

confidence: 88%

Design and construction of a microcoil NMR probe for the routine analysis of 20‐μL samples

Henry

Park

et al. 2008

Concepts Magn Reson

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Recent advances in microcoil NMR have provided commercially available, robust methodologies for analyzing mass and volume limited samples in the low microliter regime, and the technology has been applied in a number of areas. Unfortunately, due to constraints on sample size and the limited solubility of some compounds of interest, the application of this approach to certain areas of development, such as the structural analysis of chromatography eluates, is restricted. A current challenge is to provide an option within a previously unexplored sample size regime (tens of microliters) while still taking advantage of the increase in mass sensitivity afforded by solenoidal microcoil NMR. In this article, we present the design and construction of a microcoil NMR probe with a custom detection cell for the routine analysis of 20-lL samples. The detection cell is comprised of a CO 2 -laser-heated HF-etched borosilicate active volume with fused silica transfer lines added to provide sample input and output. This setup produces an enlarged sample bubble within the detection coil and provides easy connection with 1/16 in. standard LC connections, lending itself to applications with HPLC-NMR, online SPE and similar separation techniques, as well as higher-throughput robotic automation. NMR performance characteristics determined using standard compounds showed the probe exhibited reasonable resolution (<0.01 ppm), although sensitivity was less than optimal due to tuning constraints. Future improvements and opportunities are also discussed.

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“…6 Direct 13 C observation using solenoidal capillary probe (cell volume 5 mL, sensitive volume 1.5 mL, 330 mg of menthol, 150 MHz observation frequency); broad signals between 80 ± 120 ppm are probe background. Reproduced from [71] by permission of the American Chemical Society.…”

Section: Discussionmentioning

confidence: 99%

“…However, the main potential of microcoils is in their combination with microflow liquid Review 799 chromatography, resulting in capillary HPLC-NMR [67], [68], [69], [70], [71], [72], [73], [74]. Stopped-flow capillary HPLC-NMR was recently used for the identification of isoflavonoids in plant material [75].…”

Section: Other New Trends In Nmr Hyphenationmentioning

confidence: 99%

Untitled

2005

Planta Med

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IntroductionIn the first part of this review [1], the use of direct NMR hyphenation in natural products research has been discussed. The direct HPLC-NMR methods were defined as methods in which the NMR data acquisition is performed on the HPLC column eluate [1]. This implies either a direct connection between the NMR spectrometer and the HPLC apparatus, or use of storage capillaries in which the HPLC eluate is temporarily stored prior to acquisition of NMR data.Many useful results related to natural products have been obtained using direct HPLC-NMR methods [1] [30]. However, the direct combination of state-of-the-art separation technology with the most powerful and versatile tool for structure elucidation of organic molecules in solution suffers from various practical problems. In short, these practical limitations are due to somewhat contradictory requirements of HPLC and NMR with respect to solvents and time-scale of the experiment, and thus compromises are necessary in order to hyphenate these two techniques. For example, 1 H-NMR spectra are preferably acquired in deuterated solvents, but use of deuterated solvents for HPLC is expensive and the selection is limited. Some useful HPLC eluents, such as buffers with high ionic strengths, are directly undesirable in direct HPLC-NMR hyphenation. Gradient elution of HPLC columns, required in most separations, implies constantly changing magnetic susceptibility and field homogeneity in the NMR flowprobe, not to mention variations of analyte chemical shifts with solvent composition. Hyphenated NMR Methods in Natural Products AbstractThis review describes the principles and performance of a novel and highly promising hyphenated technique, HPLC-SPE-NMR, which is based on post-column analyte trapping by solid-phase extraction. The analytes are subsequently eluted from the SPE cartridges using deuterated solvents. This indirect HPLC-NMR hyphenation offers numerous advantages compared to direct HPLC-NMR methods. Multiple trapping leads to a dramatic increase of analyte amounts available for NMR, enabling acquisition of high-quality 2D NMR data within a short time. Other new developments, including combination of solenoidal coil capillary flow-probes with microflow HPLC, are also discussed. Fast extract dereplication using these techniques enables focusing of isolation efforts on truly novel and promising natural products, based on precise structural data obtained with crude extracts or fractions.

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Microflow NMR: Concepts and Capabilities

Cited by 130 publications

References 22 publications

Spatial and Temporal Dynamics of Jasmonate Synthesis and Accumulation in Arabidopsis in Response to Wounding

Spatial and Temporal Dynamics of Jasmonate Synthesis and Accumulation in Arabidopsis in Response to Wounding

Design and construction of a microcoil NMR probe for the routine analysis of 20‐μL samples

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