在线热裂解/气相色谱-质谱分析3-吡啶甲酸茴香酯的热裂解产物

采用在线热裂解/气相色谱-质谱(Py/GC-MS)联用技术对3-吡啶甲酸茴香酯进行热裂解分析。通过酰氯化和酯化反应合成了新型目标化合物3-吡啶甲酸茴香酯,其分子式为C14H14NO3。目标化合物的结构经核磁氢谱(1H NMR)、核磁碳谱(13C NMR)、红外光谱(IR)和高分辨质谱(HRMS)进行确证,并通过热重-微热重-差示扫描量热(TG-DTG-DSC)分析方法对目标化合物的热稳定性进行分析。在空气氛围中,将目标化合物分别于300,600,900℃下进行热裂解,并通过气相色谱-质谱法对其挥发性热裂解产物进行定性和半定量分析。研究显示:目标化合物共经历了两次失重过程。第一次失重在129.9~158.9℃之间,失重2.3%;第二次失重在158.9~274.9℃之间,失重达90.1%,230.1℃时失重率最大。热裂解共产生44种产物,包括具有香味特征的大茴香醛、对甲基苯酚、松油醇、D-香茅醇、大茴香醚和茴香醚等化合物。其中裂解温度对裂解产物的种类和相对含量具有明显影响。300℃时α-二去氢菖蒲烯的相对含量最高,600,900℃时,相对含量最高的分别是大茴香醛和对甲基苯酚。苯甲醛、茴香醚和大茴香醚的相对含量随着温度的升高呈先增加后降低趋势;而对甲基苯酚含量则随着温度的升高而增加。根据主要裂解产物及其相对含量的变化,对目标化合物的裂解机理进行了初步探讨。     

裂解气相色谱法分析铸造用聚苯乙烯泡沫塑料热解产物

采用裂解气相色谱法研究了汽化模铸造工艺用聚苯乙烯泡沫塑料在４５０～１０００℃温度范围内热分解产物的分布,定量测定了４种主要蒸气态热分解产物的含量。结果表明,所采用的分析方法对研究铸造用高分子材料热分解产物行之有效,而且方法简单、快速、准确。     

Gas Chromatographic Determination of Trimethylsilyl Derivatives of Free Amino Acids from a Botanical Source

Abstract

The application of gas chromatography for the separation of TMS-amino acids from a botanical source was demonstrated. The trimethyl-silyl derivatives of the extracts from germ free tobacco tissue cultures were prepared by reacting amino acid extracts with bis(trimethylsilyl)-trifluoroacetamide (BSTFA) using acetonitrile as a reaction solvent following preliminary separation of the free acids by ion exchange chromatography. Gas chromatographic separation was accomplished with a 10% OV-11 glass column and temperature programming. The findings compare favorably with other chromatographic methods. Structures of the TMS-amino acids were confirmed by gas chromatography-mass spectrometry combination. Mass spectral data for each derivative is presented for the principal protein amino acids observed as well as γ-aminobutyric acid, asparagine, α-aminobutyric acid and β-alanine.     

裂解气相色谱-质谱法研究壬酸香草酰胺的热裂解

采用在线热裂解/气相色谱-质谱联用技术(Py/GC-MS)对壬酸香草酰胺(PAVA)的热裂解行为进行了研究,在氦气氛围中考察了不同裂解温度和裂解时间对PAVA裂解的影响,通过GC-MS对裂解产物进行定性和半定量分析。结果表明,随着裂解温度的升高,PAVA裂解率快速提高,裂解产物也进一步增多,当裂解温度达到700℃以上时,可裂解出壬酰胺、2-甲氧基-4-甲基苯酚、1-己烯、壬基腈、壬醛等14种产物。同一温度下随着裂解时间的延长,PAVA的裂解率逐步升高,裂解产物发生了进一步的裂解。根据热裂解产物及主要裂解产物的含量变化,初步推断了PAVA的裂解规律。     

High-Performance Liquid Chromatographic Analysis of Amino Acids in Edible Seaweeds after Derivatization with Phenyl Isothiocyanate

Summary A reversed-phase high-performance liquid-chromatographic method has been used for analysis of the amino acids in edible seaweed. Sample proteins were hydrolysed with hydrochloric acid and the amino acids produced were derivatized with phenyl isothiocyanate. The resulting phenylthiocarbamyl amino acids were chromatographed on an ODS2 column with UV detection at 254 nm. The mobile phase was a mixture of 0.14 M ammonium acetate buffer, pH 6.4, containing 0.05% triethylamine (A) and 60:40 (v/v) acetonitrile–water (B), at a flow rate of 1.1 mL min^–1; the elution gradient (min:A%) was: 0:90, 8:90, 10:70, 12:70, 18:52, 20:0, 25:0, 28:90, 35:90. Method precision for the different amino acids was between 1.33 and 3.88% (relative standard deviation); detection limits were between 6.9 and 14.3 ng mL^–1. The amino acid content of the algae analysed ranged from 22.4 ± 1.9 to 138.0 ± 5.6 mg g^–1 d.w. The amino acids present at highest concentrations were glutamic acid, alanine, and phenylalanine.     

有机锗氨基酸酯类系列化合物的快原子轰击质谱规律

为增强有机锗化合物的生物活性，合成了一系列有机锗氨基酸酯类倍半氧化物，并重点研究了它们的快原子轰击质谱（ＦＡＢＭＳ）。研究结果表明：该系列化合物的各碎片离子峰与其组成及结构均有很好的对应关系及很强的规律性     

Effect of Steric Hindrance on the Resolution of the Enantiomers of Alkyl Isothiocyanate Derivatives of Amino Acids on a Teicoplanin CSP Using a Methanol-Based Mobile Phase

The effect of steric hindrance on the resolution of the enantiomers of alkyl (i.e. methyl, ethyl, propyl, butyl, and tert-butyl) isothiocyanate derivatives of amino acids on a teicoplanin chiral stationary phase (CSP), with a methanol-based mobile phase, has been studied. Resolution was found to depend on the size of the alkyl group attached to the isothiocyanate reagent and deteriorated as the size of the group increased from methyl to tert-butyl under the same chromatographic conditions. This indicates that interaction between the isothiocyanate group and the chiral selector is important in chiral recognition. Better-than-baseline resolution was achieved for many amino acids with a basic amino or an amide group, for example histidine, lysine, arginine, and asparagine, because of increased solubility in the mobile phase after chemical derivatization. Revised: 22 September and 7 October 2005     

Amino Acid Derivatives and Oximes of Flavones

4-Ethoxyflavylium tetrafluoroborates with substituents in rings A and B were synthesized. Their reaction with nitrogen-containing nucleophiles was investigated. It was shown that derivatives of flavones at the carbonyl group are formed as a result of these reactions. The major distinctive physicochemical characteristics of the oximes of flavones and isoxazoles were determined.     

榴莲中脂肪酸成分的色谱-质谱分析

报道了用色谱－质谱分析榴莲中的脂肪酸及其含量。结果表明榴莲含有丰富的对人体有益的脂肪酸,是一种具有较高食用价值和药用价值的水果。     

Pyrolysis-GC/MS of Menthyl Esters of N-Benzoxycarbonyl Amino Acid

With the aid of a Pyrolysis-GC/TOF MS technique,the pyrolysis behaviour of two menthyl esters of N-benzoxycarbonyl amino acid was investigated.A clear pattern emerges involving the cleavage of the bond linking the menthyl ring to the carboxy group,followed by further degradation of the fragments.The major pyroproducts were p-menth-1-ene pyrolysed at a higher temperature or p-menth-2-ene pyrolysed at a lower temperature,and va-rious derivatives of cyclohexene pyrolyzed from the menthyl ring.In addition,some ...     

各种氨基酸衍生物在Chirasil—Val固定相上的气相色谱分离

本文叙述氨基酸及其对映体的全氟酰基烷基脂(O-异丙基、-异丁基、-正丁基;N(O,S)-三氟乙酰基,TFA、-七氟丁酰基,HFB)在Chirasil-Val上的洗脱特性。随烷基取代增大,保留时间增加;用HFB代替TFA,对映体的分离因子降低。此外,DL-氨基酸与另丁醇衍生,生成的对映及非对映衍生物在Chirasil-Val上可拆分成四个色谱峰。     

反相高效液相色谱测定依替巴肽注射液中氨基酸的含量

采用异硫氰酸苯酯为柱前衍生化试剂,结合反相高效液相色谱技术,建立了定量分析依替巴肽注射液中氨基酸组分的检测方法。优化色谱条件,选用Agilent XDB-C18色谱柱(5μm,150 mm×4.6 mm),以0.1 mol/L醋酸钠(冰醋酸调至pH 6.0)-乙腈(90∶10)为流动相A,乙腈为流动相B,梯度洗脱方式,检测波长为254 nm,流速为1.0 mL/min,进样体积为5μL,柱温为30℃。结果表明,在优化条件下,各氨基酸能实现有效分离,且在1.23～3.68 mmol/L浓度范围内,各氨基酸的线性关系良好,相关系数(r)为0.999 1～0.999 6。该方法显示了良好的准确性、重复性、稳定性及选择性,能对依替巴肽注射液中的氨基酸实现准确定量分析。     

一些土壤和有机肥中氨基酸测定方法研究

一些土壤和有机肥中氨基酸测定方法研究袁吕江，熊凤麒，王正银（西南农业大学中心实验室重庆６３０７１６）（西南农业大学土化系重庆６３０７１６）关键词液相色谱法，氨基酸，土壤，有机肥１前言我国耕作土含氮量为０．４～３．８ｇ／ｋｇ［１］，其中９０％～９８％为...     

一种氨基酸衍生物消旋的新方法

报道了一种氨基酸衍生物消旋的新方法。以苯甘氨酸甲酯为反应模板,考察了催化剂、反应时间、反应温度和溶剂对氨基酸酯消旋的影响。在最优反应条件［甲苯为溶剂,DABCO 20 mol%和邻羧基苯甲醛20 mol%为催化剂,于50 ℃反应6 h］下,消旋率可达100%。     

手性锌卟啉与氨基酸酯的分子识别性能

通过紫外-可见光谱滴定法, 研究了手性锌卟啉配合物[p-(L-Leu)C2O-TPPZn]与手性氨基酸酯客体在CHCl3中的分子识别行为. 实验结果表明, D型氨基酸酯的缔合常数比L型的大, 且缔合常数按K(AlaOCH3)相似文献   

Hydrolysis of Lipophilic Amino Acid Esters Catalyzed by Metallomicelles

Metallomicelles as the model of hydrolytic metalloenzymes have begun recently¹. Examples are the metal-ion complexes of lipophilic imidazoles² and pyridines³ co-micelled with surfactants. Herein we report the complexes of a novel macrocyclic 12-membered di-oxotetraamine ligand bearing bis-hydroxy groups as functional pendants which can mimic the catalytic function of carboxypeptidase A in micellar media.     

糖基修饰的氨基酸类化合物的合成

通过对5种氨基酸酯化和氨基保护得到苄氧羰基氨基酸甲酯, 经肼解制备苄氧羰基氨基酸酰肼, 然后分别与3种不同的糖基异硫氰酸酯反应, 制备了相应的目标化合物15个, 且产率均在60%以上. 所有新化合物均经元素分析, IR, MS和¹H NMR确证. 同时探索了苄氧羰基氨基酸甲酯肼解的最佳反应条件.     

氨基酸衍生物PMV，PML和PMA的电喷雾质谱研究

应用电喷雾（ESI）质谱及其多级串联质谱（MS~n）技术研究了三个氨基酸衍 生物N-(N-亚甲基-2-吡咯烷酮）-缬氨酸（PMV），N，N-二-（N-亚甲基-2-吡咯烷 酮）-亮氨酸（PML）和N，N-二-（N-亚甲基-2-吡咯烷酮）-β-丙氨酸（PMA）在电 喷雾条件下的质谱行为。在此条件下三个氨基酸衍生物PMV，PML和PMA可以质子化 形式PMVH~+，PMLH~+和PMAH~+存在，并且检测到它们的Na~+和K~+的加合物。在电 喷雾条件下PMV，PML和PMA优先采取C-N键的断裂，并且通过分子间的氢键作用形成 了许多二聚和三聚物种。     

Catalytic Hydrolysis of Lipophilic Amino Acid Esters by Metallomicelles as Carboxypeptidase A Models

Metallondcellesasthemodelofhydrolyticmetalloenzymes.havebegunrecently'.Exam-plesarethemetal-ioncomplexesoflipophilicinddazoles2andpyridines'co-ndcelledwithsurfactantS.Hereinwereportthecomplexesofanovelmacrocyclicl2-membereddioxotetradrineligandbearingbis-hydroxygroupsasfunctionalpendantSwhichcanmindcthecatalyticfunctionofcarboxypeptidaseAinndcellarmedia.2,6-Dioxo-l,4,7,lo-tetraazacyclo1(O.2Og,1.onuno1)'anddodecylglycidylether(O.54g,2.2nunol)'wererefluxedinEtOH(3OoInL)for24h.Thesolventwase…     

Ion-Molecule Reaction Products Found in the Mass Spectra of Trimethylsilyl Derivatives

Abstract

Mass spectrometric studies of trimethylsilyl derivatives of glycerophosphates revealed the presence of several ions of mass greater than M⁺. It is suggested that these ions are formed by the reaction of abundant fragment ions containing positively charged silicon with neutral molecular species.