Capture of the volatile carbonyl metabolite of flecainide on 2,4-dinitrophenylhydrazine cartridge for quantitation by stable-isotope dilution mass spectrometry coupled with chromatography

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• 作者：Laszlo Prokai^a ; ^{Laszlo.Prokai@unthsc.edu} ; Szabolcs Szarka^a ; Xiaoli Wang^a ; ¹ ; Katalin Prokai-Tatrai^a ; ^b
• 关键词：Volatile carbonyl metabolite ; 2 ; 4-Dinitrophenylhydrazine (DNPH) cartridge ; 15N-labeled internal standard ; GC&ndash ; MS ; LC&ndash ; MS
• 刊名：Journal of Chromatography A
• 出版年：2012
• 期刊代码：47_00219673
• 类别：ch
• 出版时间：6 April, 2012
• 卷：1232
• 期：Complete
• 页码：281-287
• 文件大小：750 K

摘要

Carbonyl compounds are common byproducts of many metabolic processes. These volatile chemicals are usually derivatized before mass spectrometric analysis to enhance the sensitivity of their detections. The classically used reagent for this purpose is 2,4-dinitrophenylhydrazine (DNPH) that forms the corresponding hydrazones. When DNPH is immobilized on specific cartridges it permits solvent-free collection and simultaneous derivatization of aldehydes and ketones from gaseous samples. The utility of this approach was tested by assembling a simple apparatus for the in vitro generation of trifluoroacetaldehyde (TFAA) and its subsequent capture on the attached DNPH cartridge. TFAA was generated via cytochrome P450-catalyzed dealkylation of flecainide, an antiarrhythmic agent, in pooled human liver microsomes. Stable-isotope dilution mass spectrometry coupled with GC and LC using negative chemical ionization (NCI) and electrospray ionization (ESI) was evaluated for quantitative analyses. To eliminate isotope effects observed with the use of deuterium-labeled DNPH, we selected its ¹⁵N₄-labeled analog to synthesize the appropriate TFAA adduct, as internal standard. Quantitation by GC-NCI-MS using selected-ion monitoring outperformed LC-ESI-MS methods considering limits of detection and linearity of the assays. The microsomal metabolism of 1.5 渭mol of flecainide for 1.5 h resulted in 2.6 卤 0.5 渭g TFAA-DNPH, corresponding to 9.3 卤 1.7 nmol TFAA, captured by the cartridge.