Simple device for preparing ethereal diazomethane without resorting to codistillation

Fales, Henry M.; Jaouni, T.; Babashak, J. F.

doi:10.1021/ac60335a020

Cited by 296 publications

(98 citation statements)

References 4 publications

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“…The carboxylic acid forms of the vitamin K aglycones were converted to their methyl ester derivatives by reaction with freshly prepared ethereal diazomethane generated on a small scale by a modification of a method described elsewhere (35). In brief, a mixture of 5 M KOH ( ‫ف‬ 20 ml) and diethyl ether ( ‫ف‬ 15 ml) was placed into a small, screw-capped bottle (100 ml capacity; Duran), and solid MNNG was gradually added until sufficient diazomethane was generated to turn the upper ether layer yellow (caution: only perform in a well-ventilated fume hood).…”

Section: Methylation Of Aglyconesmentioning

confidence: 99%

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

Harrington

Soper

Edwards

et al. 2005

Journal of Lipid Research

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We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their aglycone structures, 2-methyl-3-(3 -3 -carboxymethylpropyl)-1,4-naphthoquinone (5C-aglycone) and 2-methyl-3-(5 -carboxy-3 -methyl-2 -pentenyl)-1,4-naphthoquinone (7C-aglycone), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversedphase (C 18 ) solid-phase extraction (SPE), and the predominantly conjugated vitamin K metabolites were hydrolyzed with methanolic HCl. The resulting carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE. Final analysis was by reversed-phase (C 18 ) HPLC with a methanol-aqueous mobile phase. Metabolites were detected by amperometric, oxidative ECD of their quinol forms, which were generated by postcolumn coulometric reduction at an upstream electrode. The assay gave excellent linearity (typically, r 2 у 0.999) and high sensitivity with an on-column detection limit of Ͻ 3.5 fmol ( Ͻ 1 pg). The interassay precision was typically 10%. Metabolite recovery was compared with that of an internal standard [2-methyl-3-(7 -carboxy-heptyl)-1,4-naphthoquinone] added to urine samples just before analysis. Using this methodology, we confirmed that the 5C-and 7C-aglycones were major catabolites of both phylloquinone (vitamin K 1 ) and menaquinones (vitamin K 2 ) in humans. We propose that the measurement of urinary vitamin K metabolite excretion is a candidate noninvasive marker of total vitamin K status. -Harrington, D. J., R. Soper, C. Edwards, G. F. Savidge, S. J. Hodges, and M. J. Shearer. Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection. J. Lipid Res.

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Section: Methylation Of Aglyconesmentioning

confidence: 99%

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

Harrington

Soper

Edwards

et al. 2005

Journal of Lipid Research

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“…[16][17][18] The merits of the P&T method for two other methods were validated according to quantitative data, the coefficient of variation, and the lower limit of determination calculated from the standard deviation.…”

mentioning

confidence: 99%

Purge-and-Trap Gas Chromatography/Mass Spectrometry for the Analysis of Carboxylic Acids by Esterification

Ehara

Sakamoto

2000

ANAL. SCI.

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“…Under these conditions HHA eluted between 9 and 10 min, and MA eluted between 13 and 14 min. We also reacted extracts with a diethyl ether solution of diazomethane (11) to convert HHA to the more hydrophobic methyl ester, Me-HHA (Table 1). We analyzed the methylated extracts by reverse-phase HPLC using 13% methanol and 87% aqueous acetic acid (1%) as the eluant.…”

mentioning

confidence: 99%

Identification of 6-hydroxy-trans,trans-2,4-hexadienoic acid, a novel ring-opened urinary metabolite of benzene.

Kline

Robertson

Grotz

et al. 1993

Environ Health Perspect

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We studied the in vivo metabolism of benzene in mice to ring-opened compounds excreted in urine. Male CD-1 mice were treated intraperitoneally with benzene (110-440 mg/kg), [14C]benzene (220 mg/kg) or trans, trans-muconaldehyde (MUC; 4 mg/kg), a microsomal, hematotoxic metabolite of benzene. Urine, collected over 24 hr, was extracted and analyzed by HPLC with a diode-array detector and by scintillation counting. In addition to trans,trans-muconic acid, previously the only known ring-opened urinary benzene metabolite, a new metabolite, 6-hydroxy-trans,trans-2,4-hexadienoic acid, was detected in urine of mice treated with either benzene or MUC. We identified the new metabolite based on coelution of metabolites and UV spectral comparison with authentic standards in unmethylated and methylated urine extracts. Results presented here are consistent with the intermediacy of MUC in the in vivo metabolism of benzene to ring-opened metabolites. Images p310-a

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Simple device for preparing ethereal diazomethane without resorting to codistillation

Cited by 296 publications

References 4 publications

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

Purge-and-Trap Gas Chromatography/Mass Spectrometry for the Analysis of Carboxylic Acids by Esterification

Identification of 6-hydroxy-trans,trans-2,4-hexadienoic acid, a novel ring-opened urinary metabolite of benzene.

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