共查询到20条相似文献,搜索用时 185 毫秒
1.
2.
4.
乙酰葡萄糖异硫氰酸酯柱前手性衍生化拆分氨基酸立体异构体的反… 总被引:1,自引:0,他引:1
本文用乙酰葡萄糖异硫氰酸酯(GITC)作柱前手性衍生化试剂,反相高效液相色谱法拆分氨基酸立体异构成。研究了不同构型氨基酸与GITC反应后所生成的衍生物的紫外吸收响应特点。探讨了16种氨基酸GITC衍生物的色谱分离情况。 相似文献
5.
]本文应用高效液相色谱(L,L)-二肽叔丁酰胺型键合硅胶手性固定相拆分N-乙酰基--氨基酸甲酰、N-乙酰基--二茂铁基丙氨酸乙酯及N-叔丁氧羰驶基亮氨酰亮氨酸甲酯等对映异构体、结果表明:部分固定相对氨基酸衍生物对映异构体有拆分效果;大部分固定相对二茂铁基丙氨酸衍生物对映异构体有较好拆分效果;所有固定相对由(D,D)-及(L,L)-亮氨酰亮氨酸衍生物构成的外消旋体均有良好的拆分效果,分离系数最高达1.79。本文对部分化合物对映异构体的拆分机制进行了初步探讨。 相似文献
6.
7.
8.
本文利用含氢有机硅化合物与含双键的氨基酸酯的加成反应,合成了5种新的有机硅氨基酸衍生物。介绍了一种合成N-烷基取代氨基酸酯的新方法。对新化合物进行了元素和光谱分析鉴定。 相似文献
9.
含氟β-氨基酸及其衍生物具有特殊的生理活性, 其合成方法的研究近年来受到广泛关注. 以直接氟化法和间接氟化法分类, 概述了含氟β-氨基酸及其衍生物的合成方法及最新研究进展, 对一些已知化合物的生理活性及药用价值作了初步归纳. 相似文献
10.
胶束电动毛细管色谱分离氨基酸和磷酸化氨基酸 总被引:2,自引:0,他引:2
本文报道了胶束电动毛细管色谱分离、汞灯诱导荧光电荷耦合器件检测分析氨基酸和磷酸化氨基酸的 4-氟 - 7-硝基苯 - 2 - 口恶 - 1 ,3-丫唑衍生物。研究表明 ,在 p H9.35的 1 0 mmol/L硼砂和 1 0 mmol/L十二烷基硫酸钠的电泳缓冲介质中 ,5种氨基酸和 3种磷酸化氨基酸在 1 0 min内完全分离 ,检测灵敏度为 1 .2 1× 1 0 - 8~ 5 .2 1×1 0 - 8mol/L ,分离效率达 7.3× 1 0 5~ 3.0× 1 0 5/m理论塔板数 ,结果令人满意 相似文献
11.
This work focuses on the development of a suitable working procedure for preconcentration of amino acids enantiomers from water samples using a solid phase extraction. The three types of ion exchangers with various capabilities have been used. The effect of experimental conditions in SPE procedure employing strong anion exchange (SAX), weak (WCX) and strong cation exchange (SCX) cartridges (such as sample volume, pH, origin of elution solvent and its volume) on effective preconcentration of the model set of amino acids has been studied in detail. The enantiomers of isolated and preconcentrated amino acids have been analysed by GC on three capillary columns coated with chiral selectors. The different amino acids derivatives have been investigated in order to achieve optimal resolution of biogenic amino acids and their enantiomers. The best separation of amino acid enantiomers has been obtained on a Chirasil-L-Val column analysing their N-TFA methyl esters. It has been shown that SCX-SPE cartridge with sulfonic groups attached on silicagel support is most suitable for isolation and preconcentration of amino acids from water samples. For this sample treatment procedure, the overall recovery of extraction process has been calculated as an average value from three measurements. It has been found, that recoveries are practically identical for both enantiomers of a particular amino acid and varies in the range 75-99% depending on the type of amino acid. The effectivity of this sample preparation and GC method has been verified by preconcentration of amino acids from orange juice fortified by racemic mixture of some selected amino acids. 相似文献
12.
Bernal JL Nozal MJ Toribio L Diego C Mayo R Maestre R 《Journal of chromatography. A》2008,1192(2):266-272
A method using supercritical fluid extraction (SFE) and gas chromatography-mass spectrometry (GC/MS) for obtaining the amino acid profiles of genetically modified maize and soybean is proposed. SFE is carried out in a homemade modular system where amino acids are extracted with carbon dioxide modified with 35% of methanol, in conditions optimized by a central composite design. Once extracted, the amino acids are determined by GC/MS. The method has been applied to three samples of maize derived from MON810, other from NK 603 and a Roundup ready soybean sample. The profiles are compared with those obtained from their corresponding isogenic non-transgenic varieties. Although differences are directly observed in some cases by visual comparison of the chromatograms, the application of ANOVA shows more significant differences. In general terms, isogenic varieties seem to have higher content of several amino acids. 相似文献
13.
A modification of a procedure by Hage [1] is proposed for the gas chromatographic evaluation of the content of free medium-chain fatty acids and related ethyl esters in beer. The method involves extraction of free fatty acids and ethyl esters by SPE using C18 bonded phase columns, derivatization of free fatty acids and related ethyl esters with diazomethane, and GC analysis using an SP-2340 capillary column. The results obtained have shown the method to be rapid and highly reproducible. The technique has been compared with other methods used for determination of free fatty acids. 相似文献
14.
Analysis of amino acids by gas chromatography-mass spectrometry (GC–MS) requires at least one derivatization step to enable solubility in GC–MS-compatible water-immiscible organic solvents such as toluene, to make them volatile to introduce into the gas chromatograph and thermally stable enough for separation in the GC column and introduction into the ion-source, and finally to increase their ionization by increasing their electronegativity using F-rich reagents. In this work we investigated the long-term stability of the methyl esters pentafluoropropionic (Me-PFP) derivatives of 21 urinary amino acids prepared by a two-step derivatization procedure and extraction by toluene. In situ prepared trideuteromethyl ester pentafluoropropionic derivatives were used as internal standards. GC–MS analysis (injection of 1 µL aliquots and quantification by selected-ion monitoring of specific mass fragments) was performed on days 1, 2, 8, and 15. Measured peak areas and calculated peak area ratios were used to evaluate the stability of the derivatives of endogenous amino acids and their internal standards, as well as the precision and the accuracy of the method. All analyses were performed under routine conditions. Me-PFP derivatives of endogenous amino acids and their stable-isotope labelled analogs were stable in toluene for 14 days. The peak area values of the derivatives of most amino acids and their internal standards were slightly higher on days 8 and 15 compared to days 1 and 2, yet the peak area ratio values of endogenous amino acids to their internal standards did not change. Our study indicates that Me-PFP derivatives of amino acids from human urine samples can easily be prepared, are stable at least for 14 days in the extraction solvent toluene, and allow for precise and accurate quantitative measurements by GC–MS using in situ prepared deuterium-labelled methyl ester as internal standard. 相似文献
15.
Potential of fermentation profiling via rapid measurement of amino acid metabolism by liquid chromatography-tandem mass spectrometry 总被引:8,自引:0,他引:8
Dalluge JJ Smith S Sanchez-Riera F McGuire C Hobson R 《Journal of chromatography. A》2004,1043(1):3-7
Monitoring amino acid metabolism during fermentation has significant potential from the standpoint of strain selection, optimizing growth and production in host strains, and profiling microbial metabolism and growth state. A method has been developed based on rapid quantification of underivatized amino acids using liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) to monitor the metabolism of 20 amino acids during microbial fermentation. The use of a teicoplanin-based chiral stationary phase coupled with electrospray tandem mass spectrometry allows complete amino acid analyses in less than 4 min. Quantification is accomplished using five isotopically labeled amino acids as internal standards. Because comprehensive chromatographic separation and derivatization are not required, analysis time is significantly less than traditional reversed- or normal-phase LC-based amino acid assays. Intra-sample precisions for amino acid measurements in fermentation supernatants using this method average 4.9% (R.S.D.). Inter-day (inter-fermentation) precisions for individual amino acid measurements range from 4.2 to 129% (R.S.D.). Calibration curves are linear over the range 0-300 microg/ml, and detection limits are estimated at 50-450 ng/ml. Data visualization techniques for constructing semi-quantitative fermentation profiles of nitrogen source utilization have also been developed and implemented, and demonstrate that amino acid profiles generally correlate with observed growth profiles. Further, cellular growth events, such as lag-time and cell lysis can be detected using this methodology. Correlation coefficients for the time profiles of each amino acid measured illustrate that while several amino acids are differentially metabolized in similar fermentations, a select group of amino acids display strong correlations in these samples, indicating a sub-population of analytes that may be most useful for fermentation profiling. 相似文献
16.
Simultaneous determination of thirteen kinds of amino acid and eight kinds of acylcarnitine in human serum by LC–MS/MS and its application to measure the serum concentration of lung cancer patients 下载免费PDF全文
Easy‐to‐use early cancer detection methods based on metabolomics using serum samples have been developed recently. Among metabolites, amino acids and acylcarnitine are two of the most suitable candidates for diagnosing lung cancer. The purpose of the present study was to develop a novel, sensitive and specific liquid chromatography–tandem mass spectrometry (LC–MS/MS) method to simultaneously determine 13 amino acids and 8 acylcarnitines in lung cancer patients in serum. After derivatization, the 21 analytes were separated using a C18 column with gradient elution program in 14 min, obtaining recovery within 90.4–113.8% and precision within 0.3–14.8%. The method was successfully applied in concentration determination of lung cancer patients and healthy controls. The results showed that the serum concentration of lung cancer patients were significant from those of healthy controls. 相似文献
17.
Hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method for the simultaneous determination of l‐valine,l‐leucine,l‐isoleucine,l‐phenylalanine,and l‐tyrosine in human serum 下载免费PDF全文
Beibei Gao Qingyun Yuanzi Hongwen Zhang Yongqing Wang Ning Ou Hongwen Zhou 《Journal of separation science》2015,38(22):3876-3883
l ‐Valine, l ‐leucine, l ‐isoleucine, l ‐phenylalanine, and l ‐tyrosine are important proposed biomarkers for the early detection and diagnosis of type 2 diabetes. A simple and selective hydrophilic interaction chromatography with tandem mass spectrometry method was developed for the simultaneous determination of these amino acids in human serum, using stable isotope‐labeled amino acids as internal standards. Chromatographic separation was carried out on a Syncronis HILIC column (150 mm × 2.1 mm, 5 μm) with the column temperature of 35°C and a mobile phase consisted of acetonitrile/120 mM ammonium acetate (89:11, v/v), and the run time was 11.0 min. The mass spectrometric analysis was performed using a QTRAP 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. As these five amino acids are endogenous compounds in serum, we used the corresponding stable isotope‐labeled amino acids to evaluate the matrix effect and recovery in serum. The matrix effect was 98.7–107.3%, and the recovery was 92.7–102.3%. Calibration curves spiked unlabeled amino acids in water were linear over the range of 0.200–100 μg/mL. The accuracy, inter‐, and intraday precision were below 10.2%. Analytes were stable during the study. This assay method has been validated and applied to the early diagnosis research of type 2 diabetes. 相似文献
18.
气相色谱/质谱法分析孔石莼中的脂肪酸 总被引:3,自引:0,他引:3
建立了孔石莼脂肪酸的气相色谱/质谱(GC/MS)测定方法。使用Folch法提取了孔石莼中的总脂,经过2 mol/L HCl-甲醇溶液的甲酯化处理后,采用GC/MS法对其脂肪酸组成进行了分离分析,同时结合有机质谱学规律,分别对饱和脂肪酸甲酯、单不饱和脂肪酸甲酯和多不饱和脂肪酸甲酯的裂解规律和质谱特征进行了分析归纳。通过质谱数据库检索和标准品对照,鉴定出孔石莼中的24种脂肪酸,其中9,12,15-十八碳三烯酸、4,7,10,13-十六碳四烯酸和6,9,2,15-十八碳四烯酸3种主要多不饱和脂肪酸占总脂肪酸含量的45.14%。通过对孔石莼中脂肪酸的分析,表明特征离子在脂肪酸甲酯尤其是多不饱和脂肪酸甲酯的定性方面具有很好的应用价值。 相似文献
19.
Summary The chromatographic behavior of twelve dansyl DL amino acids, one D isomer and eleven L isomers on RP18W/UV254, RP18W/F254s, and Sil C18–50 UV254 plates developed with aqueous—organic solutions containing bovine serum albumin (BSA) as chiral complexing agent has been extensively investigated. Enantiomeric resolution is highly dependent on mobile phase pH and ionic strength, and on the concentration of both BSA and organic modifier. All the racemates have been resolved within a development time of 1 h 30 min. The selectivity factors () for the dansyl amino acids have been compared with those from planar chromatography for the corresponding DNP, DNPy, and Fmoc amino acids, and with those of the same dansyl derivatives on a column prepared from BSA bound to silica gel. 相似文献