Direct extract derivatization for determination of amino acids in human urine by gas chromatography and mass spectrometry

Namera, Akira; Yashiki, Mikio; Nishida, Munehiro; Kojima, Tohru

doi:10.1016/s1570-0232(02)00075-2

Cited by 69 publications

(40 citation statements)

References 8 publications

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“…There is no need to extract FFAs into the organic phase before derivatisation or to evaporate water; consequently loss of watersoluble SCFFAs is prevented. Moreover, the ECF derivatisation reaction is a two-step reaction, and it is a simple and fast procedure (Namera, Yashiki, Nishida, & Kojima, 2002) that facilitates improved reproducibility and satisfactory derivatisation efficiency. Alkyl chloroformates were described as the preferred derivatising reagents of carboxylic acids as they react very rapidly under mild conditions (Christie, 1993).…”

Section: Derivatisation Proceduresmentioning

confidence: 99%

Novel method for quantification of individual free fatty acids in milk using an in-solution derivatisation approach and gas chromatography-mass spectrometry

Amer

Nebel

Bertram

et al. 2013

International Dairy Journal

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a b s t r a c tAn ethyl chloroformate free fatty acid (ECF-FFA) method was developed for quantification of free fatty acids (FFAs) in milk. The method is based on gas chromatography mass spectrometry with ECF insolution derivatisation and was optimised for the comprehensive analysis of FFAs (C 4 eC 18:3 ) in bovine milk. Good estimations of all FFAs, including the most water-soluble short chain free fatty acids were achieved by using in-solution derivatisation, which can be ascribed to the fact that an extraction of the milk samples with an organic phase is avoided. FFA standard solutions and raw milk samples were used to validate the proposed method. Correlation coefficients of >0.999 were obtained for all of the standards. Both the repeatability and the within three days stability of the analytical method were high (RSD <4%) for the quantified FFAs in milk. Method recovery of spiked milk samples with three different levels of FFAs was in the range 94e103%.

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Section: Derivatisation Proceduresmentioning

confidence: 99%

Novel method for quantification of individual free fatty acids in milk using an in-solution derivatisation approach and gas chromatography-mass spectrometry

Amer

Nebel

Bertram

et al. 2013

International Dairy Journal

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“…These methods include capillary electrophoresis (CE) [2][3][4][5][6][7][8][9], capillary electrophoresis coupled to electrospray ionization mass spectrometry [10], micellar electrokinetic capillary chromatography [11], high performance liquid chromatography [12][13][14][15][16], ion exchange chromatography [17,18], gas chromatography [19], gas chromatography-mass spectrometry [20], and stripping square wave voltammetry [21]. The official method presented in the European Pharmacopoeia for their pure form assay involves titrimetry with hydrochloric acid using methyl red mixed solution as indicator (ARG) and potentiometric titrimetry with hydrochloric acid (HIS) or perchloric acid (LYS) [22].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Determination of Essential Basic Amino Acids in Pharmaceuticals by Capillary Isotachophoresis

Kubacák¹,

Mikuš

Valášková

et al. 2006

Archiv der Pharmazie

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Capillary isotachophoresis (ITP) in cationic regime of the separation with conductometric detection has been used for the separation and determination of basic amino acids (arginine, histidine, and lysine) in pharmaceutical preparations. Several electrolyte systems of different compositions and pH were examined. The optimized ITP electrolyte system consisted of 10 mmol/L potassium acetate adjusted to pH 4.0 with acetic acid as the leading electrolyte with the electroosmotic-flow (EOF) suppressing additive, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC), and 10 mmol/L beta-alanine as the terminating electrolyte. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid and highly reproducible assay of these amino acids. Good quantitation was obtained in short analysis times (a single analysis took about 10 min). The minimal sample pretreatment and low running costs make the proposed ITP method a good alternative to commonly used analytical methods. The obtained results suggest that the proposed method is suitable for routine assay of basic amino acids in pharmaceuticals.

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“…3,14) In contrast to the previously reported methods, this derivatization method with ethyl chloroformate using the HPLC-MS system offers the advantages of less time required for the derivatization process and the ability to be performed in aqueous media. 33) In addition, this derivatization demonstrated satisfactory derivatization efficiencies with good yield in a short reaction time and enhanced data collection 34) because not only the levels of 5-HT, DA and their metabolites were simultaneously determined, but each peak area of 5-HT, DA and their metabolites was significantly expanded and more sensitive than those generated when using the HPLC-ECD method.…”

Section: Application Of the Methods To Real Biological Samplesmentioning

confidence: 97%

Simultaneous Measurement of Serotonin, Dopamine and Their Metabolites in Mouse Brain Extracts by High-Performance Liquid Chromatography with Mass Spectrometry Following Derivatization with Ethyl Chloroformate

Park

Myung

Kim

et al. 2013

Biological & Pharmaceutical Bulletin

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In order to measure the levels of serotonin (5-hydroxyltryptamine, 5-HT), dopamine (DA), 3,4-hydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3-MT) and homovanillic acid (HVA) simultaneously, an effective derivatization method followed by high-performance liquid chromatography (HPLC) coupled to electrochemical ionization mass spectrometry was used. The derivatization reaction of biological samples with ethyl chloroformate occurred rapidly at room temperature in aqueous conditions, and the resulting derivatives were isocratically separated with good selectivity using a C18 reversed-phase column within 30 min. The study results showed that the new derivatization procedure offers an excellent means of simultaneous determination of 5-HT, DA and their metabolites in mouse brain homogenates, which are important in a number of physiological and behavioral functions.Key words neurotransmitter; HPLC-MS; ethyl chloroformate; derivatization Dopamine (DA) and serotonin (5-hydroxyltryptamine, 5-HT), which are widely distributed as a monoamine neurotransmitter in the central nervous system (CNS), 1) play important physiological and behavioral roles such as the control and regulation of affective behavior, sleep, reward system, motor and cognitive functions.2) Changes of DA and 5-HT basal levels have been linked to some CNS-related disorders such as depression, panic disorder, schizophrenia and Parkinson's disease (PD).2,3) PD is pathologically characterized by the death of dopaminergic neurons in the substantia nigra pars compacta 4) and caused by neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahypyridine (MPTP), which produces a clinical syndrome similar to PD. Because the administration of MPTP is known to affect the dopaminergic neurons in the nigrostriatal system with subsequent depletion of DA and its metabolites, 5,6) the measurement of 5-HT, DA and their metabolites is necessary to discover and test new drugs for treating these disorders. 7)Various analytical methods have been widely investigated for determining the level of monoamine neurotransmitters and their metabolites, including high-performance liquid chromatography (HPLC) coupled with electrochemical detection (ECD), dual ECD, fluorescence detection (FLD), FLD/ECD system, chemiluminescence detection and mass spectrometer (MS) and gas chromatography (GC) coupled with MS in biological samples such as plasma, rat brain, and mouse brain and in vitro experiments.8-10) HPLC-ECD, which is the most common analytical technique used to determine monoamines and their metabolites, has the advantages of low cost and fast speed 11) but maintaining its routine use is problematic due to sudden noise problems.12) The HPLC-FLD method is used to measure fluorescent derivatives of monoamine neurotransmitters by a derivatization procedure, 13) which was performed by benzylamine and 1,2-diphenylethylenediamine in a two-step reaction in weakly alkaline media and in the presence of potassium hexacyanoferrate (III).14) However, since this protocol requires the vigorous reaction ...

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Direct extract derivatization for determination of amino acids in human urine by gas chromatography and mass spectrometry

Cited by 69 publications

References 8 publications

Novel method for quantification of individual free fatty acids in milk using an in-solution derivatisation approach and gas chromatography-mass spectrometry

Novel method for quantification of individual free fatty acids in milk using an in-solution derivatisation approach and gas chromatography-mass spectrometry

Simultaneous Determination of Essential Basic Amino Acids in Pharmaceuticals by Capillary Isotachophoresis

Simultaneous Measurement of Serotonin, Dopamine and Their Metabolites in Mouse Brain Extracts by High-Performance Liquid Chromatography with Mass Spectrometry Following Derivatization with Ethyl Chloroformate

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