Fatty Acid Esterification with N,N-Dimethylformamide Dialkyl Acetals for GC Analysis

Thénot, Jean-Paul; Horning, E. C.; Stafford, M.; Horning, M. G.

doi:10.1080/00032717208069552

Cited by 121 publications

(15 citation statements)

References 4 publications

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“…Because JA extracts prepared from leaf samples are green, determination of excess reagent is not possible. Therefore, we compared the efficiency of derivitization with diazomethane with that of N, N'-dimethylformamide dimethyl acetal (Thenot et al 1972) for which the number of moles of reagent is easily determined gravimetrically. Samples of ground, frozen tissue were extracted, and the pooled acetone-citric acid extracts were divided into duplicate aliquots representing 4.3202 g tissue (shoots) and 4.1377 g tissue (roots) each.…”

Section: Methodsmentioning

confidence: 99%

Quantification, correlations and manipulations of wound-induced changes in jasmonic acid and nicotine in Nicotiana sylvestris

Baldwin

Zhang

Diab

et al. 1997

Planta

283

201

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Jasmonic acid (JA) is thought to be part of a signal-transduction pathway which dramatically increases de-novo nicotine synthesis in the roots and increases whole-plant (WP) nicotine pools in response to the wounding of the leaves in Nicotiana sylvestrisSpegazzini and Comes (Solanaceae). We report the synthesis of a doubly labeled JA ([1, 2-13 C]JA) and use it as an internal standard to quantify by gas chromatography-mass spectrometry the changes in root and shoot JA pools in plants subjected to differing amounts of standardized leaf wounding. Wounding increased JA pools 10-fold locally in damaged leaves within 90 min and systemically in the roots (3.5-fold) 180 min after wounding. If JA functions as an intermediary between stimulus and response, quantitative relationships among the stimulus, JA, and the response should exist. To examine these relationships, we varied the number of punctures in four leaves and quantified both the resulting JA in damaged leaves after 90 min and the resulting WP nicotine concentration after 5 d. We found statistically significant, positive relationships among number of leaf punctures, endogenous JA, and WP nicotine accumulation. We used two inhibitors of wound-induced nicotine production, methyl salicylate and indole-3-acetic acid, to manipulate the relationships between wound-induced changes in JA and WP nicotine accumulation. Since wounding and the response to wounding occur in widely separated tissues, we applied inhibitors to different plant parts to examine their effects on the local and systemic components of this response. In all experiments, inhibition of the wound-induced increase in leaf JA 90 min after wounding was associated with the inhibition of the nicotine response 5 d after wounding. We conclude that wound-induced increases in leaf JA are an important component of this longdistance signal-transduction pathway.Abbreviations: JA = jasmonic acid; WP = whole plant; MSA = methyl salicylate

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Section: Methodsmentioning

confidence: 99%

Quantification, correlations and manipulations of wound-induced changes in jasmonic acid and nicotine in Nicotiana sylvestris

Baldwin

Zhang

Diab

et al. 1997

Planta

283

201

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“…The solvent and CuO extracts were converted to trimethylsilyl (TMS) derivatives by reaction with 100 ll of N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 10 ll of anhydrous pyridine at 70°C for 1.5 h. The extracts from base hydrolysis were first derivatized with N,N-dimethylformamide dimethyl acetal (Thenot et al 1972) and then with BSTFA and pyridine. After cooling, hexane was added to dilute the extracts prior to GC-MS analysis.…”

Section: Phospholipid Fatty Acid Analysismentioning

confidence: 99%

Soil warming and nitrogen deposition alter soil organic matter composition at the molecular-level

et al. 2015

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Rising temperatures and nitrogen (N) deposition, both aspects of global environmental change, are proposed to alter soil organic matter (SOM) biogeochemistry. For example, increased plant productivity and enhanced microbial decomposition of litter and SOM may reduce soil carbon stocks and fertility. To better understand SOM biogeochemical shifts at the molecular-level, we employed an array of biomarker and nuclear magnetic resonance (NMR) techniques to investigate the composition and degradation of SOM components in the forest floor and mineral soil horizons of warmed (5°C above average soil temperature) and N fertilized (5 g m -2 year -1 N applied in the growing season) plots from the soil warming 9 nitrogen addition study at the Harvard Forest, MA, USA. Biomarker analyses indicated increased plant-derived inputs into the forest floor under N fertilization. Soil warming promoted the decomposition of plant-derived aliphatic and cyclic compounds in the forest floor. Cutin degradation was observed in the heated forest floor which also exhibited relatively higher microbial activity. Lignin oxidation was also observed but was most pronounced in the mineral horizon of the heated plots. These results suggest that continued soil warming may promote the degradation of lignin-and cuticle-derived SOM. N fertilization also enhanced lignin oxidation but to a lesser extent likely due to a decline in microbial activity. 1 H NMR spectra of the mineral soils revealed enrichment of plant-derived alkyl structures and microbial-derived organic matter with both soil warming and N fertilization. Overall, this study shows that the decomposition and accumulation of molecularly distinct SOM components occurs with soil warming and N amendment and may subsequently alter soil biogeochemical cycling.

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“…Acid-catalyzed methylation could not be used because of the risk of addition of methanol to the conjugated double bond systems, as described by Christie (19). Alternative methylation methods, found in the literature, include diazomethane methylation (20) and those where the methylation reaction takes place in the injection port of the GC (21,22). However, the method adopted was initial hydrolysis of the oil to obtain the FFA, which were then methylated with methylchloroformate according to Hušek (18).…”

Section: Resultsmentioning

confidence: 99%

Analysis of seed oil from ricinus communis and dimorphoteca pluvialis by gas and supercritical fluid chromatography

Borch-Jensen

Jensen

Mathiasen

et al. 1997

J Americ Oil Chem Soc

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The seed oils from Dimorphoteca pluvialis and Ricinus communis contain hydroxy fatty acids. Dimorphoteca pluvialis contains ∆-9-hydroxy-10t,12t-octadecadienoic acid (dimorphecolic acid) and R. communis contains ∆-12-hydroxy9c-octadecenoic acid (ricinoleic acid). The oils were derivatized and analyzed to determine the content of hydroxy fatty acids. The trimethylsilyl fatty acid methyl ester (TMS-FAME) derivatives were analyzed by capillary gas chromatography (GC), and the free fatty acid (FFA) derivatives and the oils were analyzed by capillary supercritical fluid chromatography (SFC). Further, mass spectroscopy of the TMS-FAME derivatives was performed to check the purity of the derivatives. The results from the GC analyses of TMS-FAME corresponded to the results found by SFC analysis of the FFA. The content of ricinoleic acid in the glycerolipids of R. communis was 87.7 wt%, and the content of dimorphecolic acid in D. pluvialis was 54.0 wt%. The methods were evaluated with respect to the cost, ease, and time needed for sample preparation and analysis. JAOCS 74, 277-284 (1997).

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Fatty Acid Esterification with N,N-Dimethylformamide Dialkyl Acetals for GC Analysis

Cited by 121 publications

References 4 publications

Quantification, correlations and manipulations of wound-induced changes in jasmonic acid and nicotine in Nicotiana sylvestris

Quantification, correlations and manipulations of wound-induced changes in jasmonic acid and nicotine in Nicotiana sylvestris

Soil warming and nitrogen deposition alter soil organic matter composition at the molecular-level

Analysis of seed oil from ricinus communis and dimorphoteca pluvialis by gas and supercritical fluid chromatography

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