伊枯草菌素A发酵过程中游离氨基酸的HPLC分析

建立一种快速、高效测定游离氨基酸含量的异硫氰酸苯酯(PITC)柱前衍生高效液相色谱法,并利用此方法分析检测iturin A发酵过程中游离氨基酸的动态变化。以异硫氰酸苯酯(PITC)为衍生化试剂,采用Venusil-AA(4.6 mm×250 mm,5μm)氨基酸分析专用柱,并优化HPLC检测色谱条件。结果表明:梯度洗脱程序、流动相pH值、色谱柱温对分析时间、色谱峰分离及峰型具有重要影响。当最优色谱条件为:流动相A为0.1 mol/L无水乙酸钠缓冲溶液(pH6.4±0.1)-乙腈(66∶5),流动相B为乙腈-水(4∶1),流速1.0 mL/min,检测波长254 nm,色谱柱温40℃,梯度程序洗脱,35 min内可完全分离16种氨基酸,且各氨基酸在一定浓度范围内线性关系良好(R2均大于0.9986),加标回收率在83.84%-108.02%之间,RSD值均小于2.77%。该方法耗时短、操作简便、准确可靠,具有良好的精密度和稳定性。通过此方法研究分析伊枯草菌素A发酵过程中各游离氨基酸含量变化规律,发现其氨基酸浓度变化规律大致分为三类。     

用高效液相色谱定量分析分支链氨基酸

目的：周2,4-二硝基氟苯（DNFB）对分支链氨基酸衍生后,采用优化的高效液相色谱（HPLC）对其进行定量分析。方法：色谱柱为AgilentZORBAXEclipsAAA（4．6mm×150mm,5-Micron）,流动相为乙酸盐缓冲液（pH6．4）-乙腈,流速1．0mL／min,检测波长360nm。结果：用HPLC法测定分支链氨基酸的浓度为20-200mg／L时线性关系良好,3种分支链氨基酸的R。均在0．9997以上,平均回收率高,RSD≤0．56％（n=6）。结论：此方法快速、准确、重现性好,适合于对发酵液中分支链氨基酸的定量分析。     

高效液相色谱法制备人面果中二苯甲酮异构体环大叶藤黄醇和异大叶藤黄醇的研究

本研究报道了一种制备人面果中π键二苯甲酮异构体环大叶藤黄醇和异大叶藤黄醇的液相色谱研究方法。实验中通过色谱柱以及流动相考察,在分析色谱柱上实现了液相方法的建立、模拟及筛选试验,并在半制备色谱柱上实现了放大试验和进样量考察。优化后的色谱条件可实现异构体达到2.5的分离度,并在浓度0.2μg/μL时的进样量达到500μL,单体化合物环大叶藤黄醇和异大叶藤黄醇可通过液相色谱、核磁共振DEPT谱及质谱予以确认。该研究表明,常规C_(18)色谱柱能够对π键异构体进行拆分,将加快更多具有生物活性的二苯甲酮单体化合物的发现。     

反相高效液相色谱法测定发酵液中L-精氨酸含量

建立了一种用反相高效液相色谱测定发酵液中精氨酸含量的方法。以丙氨酸为内标物,2,4-二硝基氟苯为柱前衍生剂,用C18色谱柱在柱温30℃下,于362nm波长处检测,精氨酸质量浓度在0．Sg／L～1g／L时,其峰面积与内标物峰面积的比值和精氨酸的质量浓度的线形相关系数大于0．9998,加标回收率在104％左右。     

青藏高原红景天药材的HPLC指纹图谱

利用高效液相色谱法建立了青藏高原红景天的色谱指纹图谱。固定相采用C28反相色谱柱,流动相为甲醇：0．1%磷酸水(v／v=15：85);检测波长220nm;流速为1．0mL／min。通过比较发现红景天样品的8个主要共有峰．可作为鉴别红景天药材的主要依据。方法简便快速。为中药品种的鉴定提供了较全面的信息。     

基因重组胰高血糖素样肽-1衍生多肽的表达和产物纯化与鉴定

为研究利用基因重组方法生产人胰高血糖素样肽-1（GLP-1）衍生多肽的最佳表达及纯化条件,选用大肠杆菌偏爱密码子,以含人GLP-1的质粒为模板,用PCR方法合成全长人GLP-1衍生多肽基因,并定向插入到高效表达载体pMFH中,用大肠杆菌BL21进行表达,融合蛋白经Ni-NTA柱纯化后,用C18 Sep-Pak 反相柱脱盐,然后融合蛋白经甲酸水解,水解产物经Ni-NTA柱和高效液相色谱（HPLC）纯化制备后,目的肽由质谱鉴定。 实验结果表明：利用载体pMFH在BL21中,GLP-1衍生物的最佳诱导表达温度为37℃、诱导剂异丙基-β-D-硫代半乳糖苷（IPTG）的最佳浓度为0.6mmol/L,最佳诱导表达时间为6h;HPLC分析和制备GLP-1衍生物最佳条件为：流动相A(10% CNCH3∶90% H2O,0.1％TFA),流动相B(100% CNCH3,0.1% TFA),流速1ml／min,30 min线性梯度洗脱,B相至70%,检测波长280nm;质谱鉴定GLP-1衍生物的分子量为5.492kDa,与理论值相符合。在最佳表达及纯化条件下可得GLP-1衍生多肽的产量可达到11.6mg/L发酵产物,纯度≥98%。     

HPLC法测定血竭药材中血竭素含量的改进

本文对药其中血竭药材中血竭素的含量测定方法进行了改进,采用中性溶剂提取后用Merk RPC18柱色谱柱,流动相乙腈-0．05mol／L KH2PO4(每1000mL中含1mL H3PO4)(45：55)．流速：1mL／min分离．检测波长为440nm。实验结果显示该方法稳定、简单、快速、准确。     

高效液相色谱法测定酵母中麦角固醇含量

本文建立了酵母中麦角固醇含量高效液相色谱测定方法。其色谱条件为,色谱柱ＨＹ Ｐｅｒｓｉｌ ＢＤＳ Ｃ１８ ５ｕ反相柱,流动相为甲醇：水（９７：３）,紫外检测波长为２８３ｎｍ。酵母样加碱乙醇皂化、提取、洗涤、蒸干、定量测定。结果表明：标准曲线范围是０．０２－０．８ｍｇ／ｍｌ线性良好,最低限量为０．０１ｍｇ／ｍｌ;日内及日间ＲＳＤ（ｎ＝４）分别在２．１－４．０％和２．４－４．８％,回收率为９６．０－９     

固相萃取-高效液相色谱法测定复合薯片中丙烯酰胺

建立了一种利用固相萃取小柱与高效液相色谱联用,采用光电二极管阵列检测器测定复合薯片中丙烯酰胺的方法。以0．1％的甲酸水溶液为提取试剂,采用Waters Oasis HLB固相萃取小柱（200mg／6cc）对提取液净化处理,然后以流动相为甲醇／水（5：95,V：V）,流速为0．6mL／min,检测波长为210nm,利用AgilentC18反相色谱柱进样分析。在该条件下丙烯酰胺的回收率达80％以上,最低检测限小于10ng／mL。该方法操作简便、重复性好、稳定性高,可用于油炸复合薯片中丙烯酰胺的快速检测。     

2种HPLC-柱后衍生化-荧光检测法测定远志中黄曲霉毒素的比较

对远志中测定黄曲霉毒素的2种柱后衍生化方法(碘衍生化和光化学衍生化)进行分析比较。样品经过免疫亲和柱净化，HPLC-柱后衍生化-荧光检测器检测；采用C₁₈(250 mm×4.6 mm,5μm)色谱柱，荧光检测。柱后衍生化系统：(1)碘衍生化法，以甲醇-乙腈-水(25∶20∶55)为流动相；衍生溶液为0.05%碘溶液，流速为0.3 m L·min^-1，衍生反应温度为70℃；(2)光化学衍生化法，以甲醇-乙腈-水(35∶15∶50)为流动相。碘衍生化方法中，黄曲霉毒素B₂、G₂在3.8～19 pg范围内线性关系良好，B₁在10.4～52 pg范围内线性关系良好，G₁在10.8～54 pg范围内线性关系良好；在光化学衍生化方法中，黄曲霉毒素B₂、G₂在1.9～45.6 pg范围内线性关系良好，B₁在5.2～124.8 pg范围内线性关系良好，G₁在5.4～129.6 pg范围...     

Reversed-phase HPLC enantioseparation of pantoprazole using a teicoplanin aglycone stationary phase—Determination of the enantiomer elution order using HPLC-CD analyses

A direct HPLC method was developed for the enantioseparation of pantoprazole using macrocyclic glycopeptide-based chiral stationary phases, along with various methods to determine the elution order without isolation of the individual enantiomers. In the preliminary screening, four macrocyclic glycopeptide-based chiral stationary phases containing vancomycin (Chirobiotic V), ristocetin A (Chirobiotic R), teicoplanin (Chirobiotic T), and teicoplanin-aglycone (Chirobiotic TAG) were screened in polar organic and reversed-phase mode. Best results were achieved by using Chirobiotic TAG column and a methanol-water mixture as mobile phase. Further method optimization was performed using a face-centered central composite design to achieve the highest chiral resolution. Optimized parameters, offering baseline separation (resolution = 1.91 ± 0.03) were as follows: Chirobiotic TAG stationary phase, thermostated at 10°C, mobile phase consisting of methanol/20mM ammonium acetate 60:40 v/v, and 0.6 mL/min flow rate. Enantiomer elution order was determined using HPLC hyphenated with circular dichroism (CD) spectroscopy detection. The online CD signals of the separated pantoprazole enantiomers at selected wavelengths were compared with the structurally analogous esomeprazole enantiomer. For further verification, the inline rapid, multiscan CD signals were compared with the quantum chemically calculated CD spectra. Furthermore, docking calculations were used to investigate the enantiorecognition at molecular level. The molecular docking shows that the R-enantiomer binds stronger to the chiral selector than its antipode, which is in accordance with the determined elution order on the column—S- followed by the R-isomer. Thus, combined methods, HPLC-CD and theoretical calculations, are highly efficient in predicting the elution order of enantiomers.     

Chiral recognition ability and solvent versatility of bonded amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase: enantioselective liquid chromatographic resolution of racemic N-alkylated barbiturates and thalidomide analogs

The chiral recognition ability and solvent versatility of a new chiral stationary phase containing amylose 3,5-dimethylphenylcarabamate immobilized onto silica gel (CHIRALPAK IA) is investigated. Thus, the direct enantioselective separation of a set of racemic N-alkylated barbiturates and 3-alkylated analogs of thalidomide was conducted using different nonstandard solvents as eluent and diluent, respectively in high-performance liquid chromatography (HPLC). The separation, resolution, and elution order of the investigated compounds were compared on both immobilized and coated amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA and Chiralpak AD, respectively) using a mixture of n-hexane/2-propanol (90:10 v/v) as mobile phase with different flow-rates and fixed UV detection at 254 nm. The effect of the immobilization of the amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase on silica (Chiralpak IA) on the chiral recognition ability was noted as the bonded phase (Chiralpak IA) was superior in chiral recognition and possesses a higher resolving power in most of the reported cases than the coated one (Chiralpak AD). A few racemates were not or poorly resolved on the immobilized Chiralpak IA or the coated Chiralpak AD when using standard solvents were most efficiently resolved on the immobilized Chiralpak IA upon using nonstandard solvents. Furthermore, the immobilized phase withstands the nonstandard (prohibited) HPLC solvents such as dichloromethane, ethyl acetate, tetrahydrofuran, methyl-tert-butyl ether, and others when used as eluents or as a dissolving agent for the analyte itself. The direct analysis of a real sample extracted from plasma using DCM on Chiralpak IA is also shown.     

Predictability of Enantiomeric Chromatographic Behavior on Various Chiral Stationary Phases Using Typical Reversed Phase Modeling Software

Pharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics‐based columns (Chirobiotic V and T), polysaccharide‐based chiral column (Chiralpak AD‐RH), and protein‐based chiral column (Ultron ES‐OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. Chirality 25:506–513, 2013. © 2013 Wiley Periodicals, Inc.     

Enantiomeric separation and recognition mechanism of 2-arylpropionic acid derivatives by high-performance liquid chromatography using a chiral column

An optical resolution of the amide derivatives of ibuprofen and the carbamate-alkylester derivatives of the trans-alcohol metabolite of loxoprofen and an analogous compound, CS-670, was studied by chiral high-performance liquid chromatography (HPLC). The chiral columns SUMIPAX OA-4000 and OA-4100 were used to investigate the enantiomeric separation behavior of these derivatives using both reversed and normal mobile phases. A better separation factor (α) of the amide and the carbamate ester derivatives was obtained in the normal mobile phase than in the reversed mobile phase HPLC. In addition, the recognition mechanisms of both amide and carbamate ester enantiomers were investigated by ¹H-nuclear magnetic resonance (NMR). It is suggested that the important driving forces for the enantiomeric separation are the formation of hydrogen bonding and the charge transfer complex between these derivatives and an active site of the chiral stationary phase. © 1995 Wiley-Liss, Inc.     

Enantiomeric separation of mineralocorticoid receptor (hMR) antagonists using the Chiralcel OJ-H HPLC column with novel polar cosolvent eluent systems

This study demonstrates the increased versatility of the Chiralcel OJ-H stationary phase when using various alcohol/acetonitrile mobile phases. This chiral stationary phase has traditionally been employed in the normal phase mode and more recently with neat alcohols as eluents. Selected isomeric human mineralocorticoid receptor (hMR) antagonist pharmaceutical candidates and synthetic intermediates were separated using the Chiralcel OJ-H HPLC column with novel polar cosolvent eluent systems. The capacity factors, resolution, and selectivity of the chiral separations were assessed while varying the alcohol/acetonitrile composition and alcohol identity. The mixed polar eluents provide separations that are nearly always superior to both the traditional hexane-rich and single-alcohol "polar organic" eluents for the compounds tested in this article.     

Manipulation of chiral resolution for isoxazoline-based IIb/IIIa receptor antagonists using various mobile phase additives in subcritical fluid chromatography

Subcritical fluid chromatography (SubFC) using a carbon dioxide-methanol mobile phase is used for the chiral resolution of IIb/IIIa receptor antagonist enantiomers. The chiral resolution of three analogs, each containing two chiral centers, is optimized using various mobile phase additives. The effects that acidic, basic, and neutral additives have on retention, efficiency, and resolution are examined. The additive that gives the best resolution was found to be dependent upon the functionality and charge of the chiral analyte. For charged analytes, additives that act as competing ions of the same charge as the chiral analyte dramatically improve efficiency and resolution. Resolution of neutral chiral analyte enantiomers is also greatly affected by the choice of mobile phase additive. Chirality 10:338–342, 1998. © 1998 Wiley-Liss, Inc.     

Effect of Chromatographic Conditions on Enantioseparation of Bovine Serum Albumin Chiral Stationary Phase in HPLC and Thermodynamic Studies

Twelve chiral compounds were enantiomerically resolved on bovine serum albumin chiral stationary phase (BSA‐CSP) by high‐performance liquid chromatography (HPLC) in reversed‐phase modes. Chromatographic conditions such as mobile phase pH, the percentage of organic modifier, and concentration of analyte were optimized for separation of enantiomers. For N‐(2, 4‐dinitrophenyl)‐serine (DNP‐ser), the retention factors (k) greatly increase from 0.81 to 6.23 as the pH decreasing from 7.21 to 5.14, and the resolution factor (R_s) exhibited a similar increasing trend (from 0 to 1.34). More interestingly, the retention factors for N‐(2, 4‐dinitrophenyl)‐proline (DNP‐pro) decrease along with increasing 1‐propanol in mobile phase (3%, 5%, 7% and 9% by volume), whereas the resolution factor shows an upward trend (from 0.96 to 2.04). Moreover, chiral recognition mechanisms for chiral analytes were further investigated through thermodynamic methods. Chirality 25:487–492, 2013. © 2013 Wiley Periodicals, Inc.     

A fluorescent electrophilic reagent, 9-fluorenone-4-carbonyl chloride (FCC), for the enantioresolution of amino acids on a teicoplanin phase under the elution of the methanol-based solvent mixture

Summary. A fluorescent electrophilic reagent, 9-fluorenone-4-carbonyl chloride (FCC), is chosen to functionalize amino acids in alkaline medium before their HPLC resolution. FCC reacts with both primary and secondary amino acids to produce stable and highly fluorescent derivatives suitable for sensitive and efficient chromatographic determination and resolution on a teicoplanin chiral stationary phase (CSP) using the methanol-based solvent mixture as the mobile phase. The detection limit is in the picomole range and approximately 0.01% of the d-enantiomer in an excess of the l-enantiomer is detectable. However, the resolution is not reproducible under the elution of either the water- or the acetonitrile-based mobile phase. The increase in solubility of analyte in the mobile phase seems to be responsible. Upon comparison under the optimal chromatographic conditions, the resolution is better than that for the 9-fluorenylmethyl chloroformate (FMOC) or 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatives reported previously.     

Optimization of chiral resolution using packed columns with carbon dioxide-based mobile phases

Optimization of chiral resolution, using carbon dioxide based mobile phases, must take into consideration the individual contributions of analyte retention, selectivity, and efficiency. Each of these factors may be independently affected by changes in pressure, temperature, or state of the mobile phase. The ability to control retention by different means reflects an advantage of carbon dioxide based mobile phases over conventional HPLC mobile phases. Utilization of this advantage requires that the effects of each of these factors on each contributor to resolution be known. The cumulative effect that each of these variables has on retention, selectivity and efficiency suggests that maximum resolution is obtained using low pressures and temperatures. Maximum resolution (at fixed k′) results from low temperatures and high pressures. The latter may be of more practical importance when speed of analyses and detection limits are considered. Chirality 9:672–677, 1997. © 1997 Wiley-Liss, Inc.     

Normal phase chiral HPLC of methylphenidate: comparison of different polysaccharide-based chiral stationary phases.

A comparison of the enantiomeric resolution of (+/-)-threo-methylphenidate (MPH) (Ritalin) was achieved on different polysaccharide based chiral stationary phases. The mobile phase used was hexane-ethanol-methanol-trifluoroacetic acid (480:9.75:9.75:0.5, v/v/v/v). Benzoic acid and phenol were used as the mobile phase additives for the enantiomeric resolution of MPH on Chiralcel OB column only. The alpha values for the resolved enantiomers were 1.34, 1.29, 1.30, and 1.24 on Chiralpak AD, Chiralcel OD, Chiralcel OB (containing 0.2 mM benzoic acid in mobile phase), and Chiralcel OB (containing 0.2 mM phenol in mobile phase) columns, respectively. The R(s) values were 1.82, 1.53, 1.19, and 1.10 on Chiralpak AD, Chiralcel OD, Chiralcel OB (containing 0.2 mM benzoic acid in mobile phase), and Chiralcel OB (containing 0.2 mM phenol in mobile phase), respectively. The role of benzoic acid and phenol as mobile phase additives is discussed.