A Novel and Rapid Method for the Preparation of Methyl Esters for Gas Chromatography: Application to the Determination of the Fatty Acids of Edible Fats and Oils

McCreary, D K; Kossa, Walter C.; Ramachandran, S.; Kurtz, Richard R.

doi:10.1093/chromsci/16.8.329

Cited by 64 publications

(21 citation statements)

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“…In this case, the carboxylic end of the resulting fragment is converted to an alkoxycarbonyl group whereas the hydroxyl remains unchanged: 3 A further class of alkylating reagents, comprising tetramethylammonium hydroxide (TMAH), trimethylanilinium hydroxide and trimethylsulfonium hydroxide provides an efficient transformation of carboxylic acids into methyl esters under thermal conditions. [23][24][25][26][27][28][29] The reaction can be accomplished in a sealed tube at 300°C 30 or, most conveniently, on-line in the flash heater of a gas chromatograph at 250-300°C or even in a Curie-point pyrolyzer connected to a gas chromatograph/mass spectrometer:…”

Section: Diazomethane Is Usually Prepared By Reaction Of Nitrosomethymentioning

confidence: 99%

Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

Halket

Заикин

2004

Eur J Mass Spectrom (Chichester)

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The review is devoted to alkylation (arylation) as a widely employed derivatization procedure for the protection of OH (carboxylic acids, phosphoric acids, sulfonic acids, alcohols, polyols, phenols, enols), SH (thiols) and NH (amines, amides) groups in order to increase volatility, to improve the chromatographic properties and, if possible, mass spectral properties of derivatives. Chemical aspects of derivatization and various alkylation (arylation) reagents and reaction procedures are described. Specific mass spectral (electron ionization, chemical ionization) features of derivatives helpful in identification, structure elucidation, profiling and quantitative determination of the above-mentioned polar compounds by coupled gas chromatography or high-performance liquid chromatography are discussed. Some common analytical applications of the procedures in organic chemistry, clinical chemistry, environmental chemistry etc. are briefly summarized.

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Section: Diazomethane Is Usually Prepared By Reaction Of Nitrosomethymentioning

confidence: 99%

Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

Halket

Заикин

2004

Eur J Mass Spectrom (Chichester)

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“…16 Analysis of platelet fatty acids was performed by gas chromatography using an HP Model 5700 gas chromatograph (Hewlett-Packard, Palo Alto, Calif.) equipped with a flame ionization detector, a 50-mx 0.53-mm capillary column isothermal at 250°C, and a flow rate of N 2 of 10 ml/min. This approach permits quantification of fatty acid methyl esters with 16 and more carbon atoms.…”

Section: Platelet Fatty Acid Compositionmentioning

confidence: 99%

n-3 fatty acids and leukocyte chemotaxis. Effects in hyperlipidemia and dose-response studies in healthy men.

Schmidt

Pedersen

Varming

et al. 1991

Arterioscler Thromb

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Dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFAs) has been shown to inhibit neutrophil and monocyte chemotaxis in healthy subjects and, with respect to neutrophils, also in various patient groups. We studied the effect of dietary supplementation with n-3 PUFAs on monocyte and neutrophil chemotaxis in patients with hyperlipidemia. Chemotaxis was investigated with the under-agarose assay, using autologous serum and iV-formylmethionyl-leucyl-phenylalanine as chemoattractants. The patients were examined before and after 6 weeks of supplementation with 6 g n-3 PUFAs daily. Monocyte chemotaxis was reduced after n-3 PUFA supplementation in type Ha patients but was unaffected in patients with type IV hyperlipidemia. Furthermore, monocyte chemotaxis was increased in untreated type Ha patients compared with normocholesterolemic controls. We also studied the dose-response effects of n-3 PUFAs on monocyte and neutrophil chemotaxis in healthy men given 13, 4, and 9 g n-3 PUFAs daily for 6-week periods. Monocyte and neutrophil chemotaxis was reduced after n-3 PUFA supplements in a dose-dependent fashion, with the majority of the effect observed after the low dose. These results lend support to the notion of an antiatherosclerotic effect of n-3 PUFAs and may provide an explanation for the hitherto-unexplained effect of low doses of n-3 PUFAs in coronary heart disease. (Arteriosclerosis and Thrombosis 1991;ll:429-435)

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“…The fat from the surface layer was removed using a Pasteur pipette, stored at −20 °C, and solubilized in dichloromethane (1:9). The methyl esters were formed according to the method of McCreary, et al (1978) and quantified by gas chromatography (GC).…”

Section: Methodsmentioning

confidence: 99%

Supplementation with corn oil and palm kernel oil to grazing cows: ruminal fermentation, milk yield, and fatty acid profile

2016

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-The effect of supplementation with corn oil (CO) and its mixture with palm kernel oil (CO:PKO 75:25) to grazing cows on ruminal fermentation, milk yield, and its fatty acid (FA) profile was evaluated. The treatments were: one control treatment (C) without oil and two treatments with 720 g d −1 /cow of CO or CO:PKO (ether extract: 22.7 g kg −1 for control treatment, 66 g kg −1 for CO, and 65 g kg −1 for CO:PKO). Six multiparous Holstein cows (6.3±1.8 yr, 597±11.5 kg body weight (BW), 160±29 d in milk; mean ± standard deviation) were assigned to a double 3 × 3 × 3 Latin square design. Cows grazed (3 kg DM/100 kg BW) a Cenchrus clandestinus (previously Pennisetum clandestinum) pasture and were supplemented with 0.9 kg d −1 DM corn silage, 4.2 kg d −1 DM concentrate, and 9 g Cr 2 O 3 . The mixture of concentrate and oils was offered twice a day. The addition of oils increased milk yield (kg d −1 ) (C: 21.4, CO: 23.6, CO:PKO: 23.9) and milk fat concentration (g kg milk −1 ) (C: 31.5, CO: 34.0, CO:PKO: 34.0). Compared with control, conjugated linoleic acid (18:2 c9 t11 CLA) proportion (g 100 g −1 FA) in milk fat was higher for oil treatments (C: 0.68, CO: 1.56, CO:PKO: 1.01). Voluntary intake and digestibility were not different among treatments. The molar ratio of acetate, propionate, and butyrate was not different among treatments, but the molar concentration of volatile fatty acids (VFA) was lower for CO and CO:PKO, resulting in a lower estimated methane (CH 4 ) production (mL/100 mol VFA) for CO and CO:PKO treatments. Supplementing CO and CO:PKO to grazing dairy cows increases milk yield without affecting voluntary intake or diet digestibility. The proportion of conjugated linoleic acid increases more for CO than for CO:PKO.

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A Novel and Rapid Method for the Preparation of Methyl Esters for Gas Chromatography: Application to the Determination of the Fatty Acids of Edible Fats and Oils

Abstract: A rapid, mild, and convenient transesterification of triglycerides was obtained using 0.2 N-methanolic (m-trifluoro-methylphenyl) trimethylammonium hydroxide. The method yielded results comparable to those obtained using methanolic sodium methoxide.

Cited by 64 publications

References 0 publications

Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

Derivatization in Mass Spectrometry– 3. Alkylation (Arylation)

n-3 fatty acids and leukocyte chemotaxis. Effects in hyperlipidemia and dose-response studies in healthy men.

Supplementation with corn oil and palm kernel oil to grazing cows: ruminal fermentation, milk yield, and fatty acid profile

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