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121.
无保护流体室温燐光法测定色氨酸的研究 总被引:1,自引:0,他引:1
建立了一种仅用KI为重原子微扰剂、Na2SO3为除氧剂的无保护流体室温燐光测定色氨酸的方法,详细研究了测定条件及有机溶剂的影响。本法的线性范围为1.2×10-7~1.0×10-5mol/L,检出限为1.1×10-8mol/L,相对标准偏差2.47%~3.24%。已用于大米、花生、大豆及竹笋中色氨酸的测定,与荧光法比较,分析结果相符。 相似文献
122.
《Analytical letters》2012,45(6):397-401
Abstract L-Tryptophan is condensed with formaldehyde to yield 2,3,4,5-tetra-hydro-β-carboline-4-carboxylic acid. The trimethylsilyl derivative of this compound is suitable for selective ion monitoring during combined gas chromatography - mass spectrometry since it affords a relatively abundant molecular ion of high MSS. 相似文献
123.
We describe the synthesis, crystal structure, and various microscopic studies of the palindromic tripeptide WPW derived from antimicrobial peptide indolicidin. The present study reveals that tripeptide 1 and 2 undergo self-assembly to form vesicular structures after prolonged incubation, thus giving an interesting insight into the contribution of l-proline and flanking tryptophan residues in the self-assembly process. These vesicles were also amenable to simple focused ion beam (FIB)-aided bisection and thus possible to mill these vesicles to create different shapes. The circular dichroism (CD) analysis indicates that incubation promotes and stabilizes the more favorable secondary structures for 1 and 2. Preliminary result shows that tripeptide 1 exhibits appreciable interaction with Tb3+ as determined by quenching in tryptophan fluorescence. 相似文献
124.
《Analytical letters》2012,45(1):176-185
A poly(methyl red) film-modified glassy carbon electrode was fabricated and the oxidation behavior of tryptophan at the modified electrode was investigated by cyclic and linear sweep voltammetry. The oxidation peak current of tryptophan at the modified electrode increased significantly, and the oxidation process was irreversible and adsorption-controlled. An analytical method was developed for the determination of tryptophan in a phosphate buffer solution at pH 3.5. The anodic peak current varied linearly with a tryptophan concentration in the range 1.0 × 10?7 to 1.0 × 10?4 mol/L with a limit of detection of 4.0 × 10?8 mol/L. The proposed method was successfully applied to determine tryptophan in composite amino acid injections. 相似文献
125.
Summary Ligand-exchange micellar electrokinetic chromatography has been used for the simultaneous separation of 16 positional and
optical isomers of the tryptophan family. The Cu(II) complex with L-hydroxyproline was used as the chiral selector. Two groups
of anionic surfactant, linear alkylbenzenesulfonates (LAS) and straight-chain alkyl sulfates such as sodiumn-decyl sulfate (SDeS), sodium dodecyl sulfate (SDS) and sodiumn-tetradecyl sulfate (STS), were used for simultaneous separation. The best result was obtained by use of SDS. The influence
of SDS concentration and of pH on the separation was investigated. The separation behavior in the absence of the Cu(II) complex
with L-hydroxyproline was also examined. Use of organic modifiers causes the resolution to decrease. Relationships between
the logarithm of the octanol-water partition coefficient (logP
OW) and resolution, and between logP
OW and migration time are discussed. 相似文献
126.
色氨酸是人类一种必需氨基酸,也是稻米中一种重要的限制性氨基酸。从4年份1256份材料中选择出272份有代表性的样品,采用碱水解-分光光度法测定了其色氨酸含量。比较不同定标方法的预测结果发现,运用改良的偏最小二乘法(modified partial least square,MPLS)的全局(Global)定标方法和局部(Lo-cal)飞速定标方法的预测效果较佳,基于精米粉光谱建立的方程的预测标准误差均为0.007%,外部验证决定系数分别为87.1%和87.4%,可用于定量分析;而基于糙米光谱建立的定标方程的预测效果略差,但仍具有良好的预测能力。研究结果表明,近红外光谱技术可作为水稻育种中间材料的快速筛选和食品工业中稻米原料的品质监控手段。 相似文献
127.
An effective chiral stationary phase (CSP) for enantioseparation of amino acids was established previously by bonding (18-crown-6)-2, 3, 11, 12-tetracarboxylic acid to silica gel. This CSP has recently been commercialized under the name of Chirosil-SCA. As a first step for developing a Chirosil-SCA simulated moving bed chromatographic process for separation of tryptophan enantiomers, the adsorption isotherm and mass-transfer parameters of each tryptophan enantiomer on the Chirosil-SCA CSP were determined in this study while using only water as a mobile phase. For this task, inverse method (IM) was applied on the basis of the initial guesses estimated from elution by characteristic point (ECP) method, which was found to be more advantageous in the aspects of both accuracy and computational efficiency than the case of utilizing individually only IM or ECP method. The results revealed that the adsorption behavior of each tryptophan enantiomer on the Chirosil-SCA could be well described by the Langmuir-Freundlich isotherm. The model predictions based on the determined parameter values were in close agreement with the experimental chromatograms from a series of single-component or mixture pulse tests that were performed under various feed concentrations and flow rates. It was also found that the Langmuir-Freundlich isotherm parameters of each enantiomer were largely affected by temperature. Such a marked dependence of the parameters on temperature was investigated quantitatively. The results of such an investigation indicated that as the temperature decreases, the adsorption affinities of both enantiomers become higher and the heterogeneity of the Chirosil-SCA becomes more pronounced. 相似文献
128.
129.
不同金属离子与色氨酸作用的荧光光谱研究 总被引:2,自引:0,他引:2
研究了不同金属离子对色氨酸的荧光强度的影响。结果表明,在一定条件下当达到一定浓度时,Cu(Ⅱ),Fe(Ⅲ),Mo(Ⅵ)对色氨酸的荧光有猝灭作用,而此时Zn(Ⅱ),Mn(Ⅱ),Cr(Ⅲ),Co(Ⅱ),Ca(Ⅱ)和Na(Ⅰ)则对色氨酸的荧光几乎没有影响。 相似文献
130.