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The HPLC separation of enantiomers of underivatized non-protein amino acids was investigated by using a column packed with octadecylsilanized silica coated with N,S-dioctyl-D-penicillamine as a chiral ligand-exchange phase (Sumichiral OA-5000). Good enantiomeric separations were achieved with a variety of -amino acids carrying aliphatic or aromatic side chains, cyclic imino acids, and -amino acids, together with -methyl--amino acids, by optimizing the amount (0–20%, v/v) of 2-propanol as the organic component and the concentration (1–5 mM) of Cu2+ as the complexing metal ion in the aqueous-organic eluent. 相似文献
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《Analytical letters》2012,45(4):867-882
Abstract The enantiomeric separation by high-performance liquid chromatography of underivatized non-protein amino acids was investigated by using a column packed with octadecylsilanized silica coated with N,S-dioctyl-D-penicillamine as a chiral ligand-exchange phase (Sumichiral OA-5000). Excellent to good separations of enantiomers were achieved with a variety of nonprotein amino acids carrying aliphatic or aromatic side-chains by optimizing the amount (0-20%, v/v) of the organic component (2-propanol) and the concentration (1-5 mM) of the complexing metal ion (Cu2+) in the hydro-organic eluent. 相似文献
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Nikita Sarvin Ruslan Puzankov Georgii Vasiyarov Pavel N. Nesterenko Sergey M. Staroverov 《Molecules (Basel, Switzerland)》2023,28(1)
Macrocyclic glycopeptide antibiotics immobilized on silica are one of the effective classes of stationary phases for chiral recognition and HPLC separation of a wide range of optically active compounds. Enantioselectivity primarily depends on the chemical structure of the chiral ligand, immobilization chemistry, and separation conditions. In the present work, three new chiral stationary phases (CSPs) based on macrocyclic antibiotic eremomycin were prepared and investigated for enantioseparation of amino acids. Two eremomycin derivatives, including simple non-substituted amide and bulky adamantyl amide, provided important information on the role of the carboxylic group in the eremomycin structure in the chiral recognition mechanism concerning amino acid optical isomers. One more CSP having a chlorine atom in the same position elucidates the role of the first aromatic ring in the eremomycin structure as a crucial point for chiral recognition. CSP with immobilized chloreremomycin was the most successful among the phases prepared in this work. It was additionally investigated under various separation conditions, including the type and content of the organic solvent in the eluent, the effects of different additives, and the concentration and pH of the buffer. Importantly, an efficient enantioselective separation of amino acids was achieved with pure water as the eluent. 相似文献
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A novel norvancomycin-bonded chiral stationary phase (NVC-CSP) has been synthesized by use of the chiral selector norvancomycin, which differs from vancomycin because of the presence of leucine rather N-methylleucine. The enantiomers of some neutral and basic chiral drugs, for example warfarin, benzoin, bendroflumethiazide, and praziquantel, were directly separated by high-performance liquid chromatography in the reversed-phase mode. The effect of conditions such as organic modifier concentration, column temperature, pH, and mobile phase flow rate on retention and enantioselectivity were investigated. It was shown that hydrophobic, steric, and ionic interactions were present between the analyte and the macrocycle in this chromatographic system. Vant Hoff plots afforded the thermodynamic data R,SH° and R,SS°; the negative values obtained indicated the process of enantiomer separation was enthalpy-controlled. In an attempt to improve the resolution of some very polar acidic compounds (dansyl-amino acids) norvancomycin was used as stationary phase chiral selector and chiral mobile-phase additive simultaneously, better results were obtained as the result of a synergistic effect. It was also shown experimentally that the newly synthesized NVC-CSP behaved somewhat differently from the earlier reported vancomycin-bonded CSP, probably because of the different structures of norvancomycin and vancomycin. 相似文献
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《Analytical letters》2012,45(8):1565-1579
Abstract The synthesis of a new chiral agent, (R,R) (-)N, N'-trans-1, 2-dihexylcyclohexanediamine, for the chromatographic resolution of racemates is reported. Highly selective separations of D- and L-isomers of free and Dns-amino acids were accomplished on a reversed-phase column using in the mobile phase a Cu(II) complex of the above chiral selector. The procedure was extended to resolve diastereomeric derivatives, which were obtained by reaction of an optically active amine with o-phthaldeyde in the presence of N-acetyl-L-cysteine. 相似文献
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Two crystalline degradation products (CDP-1-M and CDP-1-m) are formed from vancomycin by hydrolytic loss of ammonia. The CDP are structurally similar to vancomycin, with two carboxyl groups, but are biologically inactive. In this work the CDP of vancomycin have been covalently linked to silica gel and their ability to resolve racemic mixtures, their stability, and their loading has been evaluated by HPLC. Elemental analysis and scanning electron microscopy were used to monitor the surface of this new stationary phase. Enantiomeric separation was achieved for some compounds that have not been previously been separated on other chiral stationary phases. 相似文献
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键合偶联双奎宁手性固定相的制备和手性拆分性能;手性固定相;奎宁;高效液相色谱;拆分 相似文献
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Xinxin Han Jeffrey W. Remsburg Lingfeng He Thomas E. Beesly Daniel W. Armstrong 《Chromatographia》2008,67(3-4):199-210
Two new synthetic polymeric chiral stationary phases (CSPs) based on trans-(1S,2S)-cyclohexanedicarboxylic acid bis-4-vinylphenylamide (I) and trans-N,N′-(1R,2R)-cyclohexanediyl-bis-4-ethenylbenzamide (II) monomers were prepared and evaluated by normal phase high performance
liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). A variety of chiral compounds were separated on
these two new CSPs. The different orientation of the amide groups in the two CSPs resulted in a striking difference in the
enantioselectivity properties of these two CSPs. Their differences in enantioselectivity with HPLC and SFC were compared. 相似文献
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Evaluation of the Temperature Responsive Stationary Phase Poly(N-isopropylacrylamide) in Aqueous LC for the Analysis of Small Molecules 总被引:1,自引:0,他引:1
F. Lynen J. M. D. Heijl F. E. Du Prez R. Brown R. Szucs P. Sandra 《Chromatographia》2007,66(3-4):143-150
Liquid chromatography columns were packed with a temperature responsive stationary phase based on poly(N-isopropylacrylamide) (PNIPAAm) attached to aminopropyl silicagel. This polymer shows hydrophilic properties below 32 °C and
becomes hydrophobic above that temperature. The temperature responsive properties of the coupled phase are demonstrated using
only water as mobile phase, whereby an increase in retention is observed with raising temperature. Mixtures of compounds covering
a wide polarity range and including phenones, alkylbenzenes, phenols, alkylated benzoic acids, anilines, sulfonamides and
carbamates were analyzed and the retention, peak shapes and plate counts were compared under identical conditions. For retained
solutes, an increase in retention as a function of the temperature between 25 and 55 °C could be noted, whereby this was higher
for the analytes containing a longer hydrophobic chain. Compounds with similar hydrophobic chains, but containing additional
polar functions showed increased retention and improved peak shapes, suggesting a mixed mode interaction mechanism also at
temperatures well above the transition temperature of the polymer. Weak acids and bases could be analyzed by pH adjustment.
This is demonstrated for mixtures of benzoic acid derivatives and sulfamide drugs. A carbamate pesticide mixture was analyzed
at 55 °C with water (pH 5.5) as mobile phase and ESI-MS detection. Temperature responsive stationary phases open perspectives
for green chromatography. 相似文献
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In recent years, the synthesis of chiral tetrahedral clusters has been studied extensively and various types are accessible , which are a kind of organometallic compounds with greatly growing interest due to their potential application to asymmetric reaction catalysts. As an efficient 相似文献
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采用高效液相色谱法在装有大环糖肽抗生素键合相的手性柱上拆分了7种氨基带有芴甲氧羰基(fluorenylmethoxycarbonyl,Fmoc)保护的氨基酸对映体。比较了Fmoc-缬氨酸和相应的不带保护基的缬氨酸对映体在不同流动相体系中的色谱保留行为;考察了甲醇-醋酸-三乙胺流动相体系中醋酸和三乙胺的浓度以及它们二者的浓度之比对N-Fmoc氨基酸对映体拆分效果的影响。实验结果表明分离温度及流动相流速的变化也会对分离结果产生影响。该法简便快速,已成功地用于这类氨基酸的光学纯度测定。 相似文献
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在正相条件下,探讨了手性化合物联萘酚、联萘酚二醋酸酯、联萘酚二磺酸酯、二溴代联萘酚、氢化安息香以及萘普生在涂敷型淀粉衍生物手性固定相Lux Amylose-2上的拆分,考察了流动相中极性醇添加剂的种类及含量、柱温等对手性拆分及对映体洗脱顺序的影响。氢化安息香获得理想的拆分,分离度可达17.76;联萘酚二醋酸酯、联萘酚二磺酸酯和二溴代联萘酚得到基线或部分分离,分离度分别为3.43、2.56和1.47;萘普生未得到拆分。联萘酚拆分中观察到溶剂诱导及温度诱导对映异构体洗脱顺序反转的现象,R-联萘酚表现出少见的吸热保留特征。结合这些现象对手性识别机理进行了探讨。 相似文献
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手性胺酰胺型液相色谱手性固定相的制备及几种氨基酸衍生物的拆分 总被引:1,自引:0,他引:1
用(R)-1-苯基2-对甲基苯基乙基胺(PTE)与L-异亮氨酸制得含两个手性中心的手性选择剂,以琥珀酸酐作为连接臂,将手性选择剂键合到氨基丙基硅胶上制得手性固定相。以正己烷-异丙醇为流动相,利用该固定相对氨基酸衍生物进行高效液相色谱手性拆分,并考察了流动相中异丙醇含量对手性拆分的影响。结果表明,该手性固定相对所分析的氨基酸衍生物大部分都具有一定的拆分能力。当异丙醇含量为1%时,亮氨酸与苯丙氨酸的苯甲酰甲酯衍生物获得基线分离。当异丙醇含量为20%时,亮氨酸、缬氨酸、丙氨酸、谷氨酸的3,5-二硝基苯甲酰甲酯衍生物获得基线分离。 相似文献
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手性锌卟啉对咪唑类客体的分子识别及圆二色光谱的研究 总被引:2,自引:0,他引:2
研究了手性α,α,α,β-四-[邻(叔丁氧羰L-酪氨酸)氨基苯基]卟啉 锌[α,α,α,β-ZnT(o-Boc)TyrTAPP](1)和手性α,α,α,β-四-[邻(叔 丁氧羰L-丙氨酸)氨基苯基]卟啉锌[α,α,α,β-ZnT(o-BocAla)TAPP](2)对 咪唑、2-甲基咪唑、N-甲基咪唑和2-乙基-4-甲基咪唑的分子识别行为,分别 求得主体(1)对咪唑类分子识别的缔合常数顺序为K(Im)>K(2-MeIm)>K(N-MeIm) >K(2-Et-4-MeIm),主体(2)对咪唑类分子识别的缔合常数顺序为K(2-MeIm)>K (Im)>K(2-Ek-4-MeIm)>K(N-MeIm),并用圆二色光谱(CD)研究了主体1和2对咪唑 在客体在CHCl3中分子识别的光谱行为,与热力学的结果做了比较。 相似文献
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Antal Pter Gabriella Trk Gza Tth Wolfgang Lindner 《Journal of separation science》2000,23(11):628-636
A quinine‐derived chiral anion‐exchange stationary phase was used for the direct high‐performance liquid chromatographic separation of the enantiomers of the N‐protected unusual β‐substituted α‐amino acids, β‐methylphenylalanine, β‐methyltyrosine, β‐methyltryptophan, and β‐methyl‐1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid. The readily prepared 2,4‐dinitrophenyl and tert‐butyloxycarbonyl derivatives were well separated, and in most cases the separation of all four stereoisomers of these β‐methyl‐α‐amino acids could be obtained in one chromatographic run. The elution sequences of the enantiomers of the different derivatives were determined and revealed a dependence on the type of the N‐protecting group. In this context, the effects of different protecting groups (acetyl, tert‐butyloxycarbonyl, benzoyl, 3,5‐dinitrobenzoyl, benzyloxycarbonyl, 3,5‐dinitrobenzyloxycarbonyl, 2,4‐dinitrophenyl, and 9‐fluorenylmethoxycarbonyl) on the chromatographic behavior were investigated. 相似文献