高效液相色谱法拆分α-氨基酸的邻苯二甲酰衍生物对映体

建立用高效液相色谱拆分α-氨基酸的邻苯二甲酰衍生物对映体的方法。用多糖类手性固定相ChiralcelOD,ChiralpakAD,ChiralpakAS柱;5%异丙醇/正己烷(V/V)含0.1%三氟醋酸溶液为流动相;流速为1mL/min;检测波长:UV=254nm。考察了α-氨基酸的邻苯二甲酰衍生物在不同手性固定相(ChiralcelOD,ChiralpakAD,ChiralpakAS柱)上的对映体的手性分离。结果表明,α-氨基酸的邻苯二甲酰衍生物对映体在ChiralcelOD柱上的分离效果最佳(α=1.34~2.11),并且全部得到了基线分离。     

高效液相手性固定相法拆分1-苯乙烯基-3-己基丙炔醇

以纤维素衍生物为手性固定相,建立药物中间体1-苯乙烯基-3-己基丙炔醇对映体的HPLC手性分析方法。以正己烷与乙醇或异丙醇为流动相,在Chiralcel OD-H手性固定相上对1-苯乙烯基-3-己基丙炔醇进行了拆分,并考察了流动相组成、流速和柱温对该对映体分离的影响,获得较优分析条件,分析时间在15 min内,分离度大于1.5。结果表明,1-苯乙烯基-3-己基丙炔醇对映体在正己烷-异丙醇(体积比90:10)为流动相、流速为1.0 m L/min、柱温为25℃时,分离效果最佳。本方法可用于1-苯乙烯基-3-己基丙炔醇对映体的质量控制。     

氟西汀衍生物对映体在纤维素手性固定相上的拆分

用纤维素-三(3,5-二甲苯基氨基甲酸酯)(Chiraleel OD)手性固定相拆分了两种氟西汀衍生物对映体。使用15cm长色谱柱分离NBD-氟西汀衍生物的流动相为四氢呋喃／正己烷(25：75),分离DBD-氟西汀衍生物的流动相为四氢呋喃／正己烷(20：80);流速为1．0mL/min,荧光检测,柱温为室温。醇类改性剂作流动相甚至不能部分拆分氟西汀衍生物。实验考察了四氢呋喃含量和柱长对手性分离的影响,探讨了手性拆分氟西汀衍生物的机理。     

9-蒽醛衍生化-高效液相色谱法拆分α-氨基酸甲酯和几种脂肪胺对映体

采用高效液相色谱法,以9-蒽醛为衍生试剂,在5种多糖衍生物的手性固定相(CSPs)上对几种α-氨基酸甲酯对映体进行了手性分离。色谱条件如下: 流动相为含3%～10%(v/v)异丙醇的正己烷溶液,流速为1.0 mL/min,检测波长为254 nm。结果表明,α-氨基酸甲酯-9-蒽醛亚胺衍生物在Chiralcel OD柱或Chiralcel OD-H柱上的手性分离结果优于其他CSPs,而且在Chiralcel OD柱或Chiralcel OD-H柱上全部得到了基线拆分(α=1.24～5.47, Rs=2.56～13.90), L-对映体在这两种色谱柱上的保留强于D-对映体。同时还考察了几种脂肪胺在5种多糖衍生物手性固定相上的对映体拆分效果,结果表明脂肪胺的9-蒽醛亚胺衍生物在Chiralcel OD柱或Chiralcel OD-H柱上的分离效果良好。该法可用于其他α-氨基酸酯和胺类化合物对映体的分析。     

2-戊基-3-苯基-2,3-环氧丙醇对映体在手性柱上的拆分研究

采用多糖类手性固定相,建立2-戊基-3-苯基-2,3-环氧丙醇对映体的高效液相色谱(HPLC)手性分析方法。考察了手性柱类型、流动相组成、流速及柱温对2-戊基-3-苯基-2,3-环氧丙醇对映体拆分的影响。结果表明,以Chiralcel OD-H色谱柱(25×0.46cm,5μm)分离,采用正己烷-异丙醇(V/V,90∶10)作流动相,在流速为0.8 mL·min-1,柱温25℃,检测波长210nm的条件下,2-戊基-3-苯基-2,3-环氧丙醇对映体能达到基线分离,且具有较好的重复性和稳定性,可用于对映体的拆分及质量控制。该方法也适用于2-戊基-3-苯基-2,3-环氧丙醇类似物质的手性拆分。     

纤维素键合手性固定相拆分喹禾灵对映体

采用Chiralpak IC(纤维素-三(3,5-二氯苯基氨基甲酸酯)键合在5μm硅胶上)键合型手性柱,建立了喹禾灵对映体的高效液相色谱拆分方法。系统考察了流动相组成、流速和柱温对喹禾灵对映体分离效果的影响。结果表明,在正己烷-异丙醇(95∶5,体积比)为流动相,流速1.0 mL/min,柱温25℃的条件下,喹禾灵对映体能获得基线分离,分离度Rs为3.97,R-构型先出峰,两对映体的检出限均为0.045 mg/L,定量下限均为0.15 mg/L。在15～35℃柱温范围内,lnα对1/T Van’t Hoff曲线呈良好的线性关系,相关系数(r2)大于0.99,分离因子α随温度升高而降低,焓变差和熵变差热力学参数显示,喹禾灵对映体的拆分过程受焓控制。     

纤维素键合手性固定相拆分6种萘满酮衍生物对映体

使用Chiralpak IC（纤维素-三（3,5-二氯苯基氨基甲酸酯）共价键合硅胶）手性柱,建立了采用手性固定相高效液相色谱拆分6种 α -芳基萘满酮类衍生物对映体的方法。考察了流动相中有机改性剂的种类和比例、柱温和流速对对映体分离的影响。结果显示6种化合物在异丙醇为改性剂的条件下均可获得较高的对映体分离度。热力学研究表明6种化合物对映体的手性拆分过程均受焓驱动影响,且低温有利于对映体分离。最终推荐分离化合物Ⅰ对映体的流动相是正己烷-异丙醇（90：10,v/v）;分离化合物Ⅱ、Ⅲ、Ⅳ对映体的流动相是正己烷-异丙醇（99：1,v/v）;分离化合物Ⅴ对映体的流动相是正己烷-异丙醇（85：15,v/v）;分离化合物Ⅵ对映体的流动相是正己烷-异丙醇（80：20,v/v）。柱温为25℃,流速为1.0 mL/min。6种化合物对映体均可在Chiralpak IC手性固定相上得到完全分离,证明该色谱柱对6种化合物具有较高的对映体选择性。     

柱前衍生化高效液相色谱手性固定相法拆分手性氰醇

利用正相高效液相色谱法在多糖衍生物手性固定相(OJ-H、OD-H、AD-H或AS-H)上成功地分离了一系列(31个)氰醇对映体的乙酰化或丙酰化衍生物,并拆分了3个脂肪族氰醇对映体的乙酰化衍生物。探讨了这些外消旋体在这四支手性柱上的色谱行为,通过考察流动相组成、流速、进样浓度和温度等因素对对映体拆分效果的影响,优化了色谱分离条件。方法已应用于脂肪酶催化转酯化拆分反应中手性氰醇衍生物的光学纯度的鉴定。     

基于直链淀粉衍生物手性固定相的高效液相色谱-串联质谱法拆分4种β-受体阻滞剂对映体及其分离机制的探讨

建立了以直链淀粉衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛4种β-受体阻滞剂对映体的方法。考察了手性固定相的种类、流动相改性剂和添加剂的体积分数、柱温和流速等对4种药物对映体分离的影响。结果表明:在Chiralpak AD-H手性色谱柱上,在正己烷-乙醇-二乙胺(20∶80∶0.03,v/v/v)为流动相、流速0.550 mL/min、柱温40℃的条件下,普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛对映体均达到基线分离,分离度分别为1.37、1.80、2.09和4.70。通过热力学研究及对映体结构分析对拆分机理进行了探讨,发现4种药物对映体的手性拆分均为焓驱动过程,而固定相的手性空腔对不同药物的拆分影响较大。研究结果为β-受体阻滞剂的深入研究提供了参考方法。     

柱前衍生化-HPLC测定仲丁胺对映体的纯度

用3, 5-二硝基苯甲酸对仲丁胺进行柱前衍生, 将其衍生物在CHIRALCEL OD-H手性固定相上拆分, 并通过二极管阵列紫外检测器对其衍生物进行检测, 建立了一种拆分仲丁胺消旋体、测定仲丁胺光学纯度的新方法. 以正己烷和乙醇或异丙醇为流动相, 在CHIRALCEL OD-H手性固定相上对仲丁胺衍生物进行了拆分, 并考察了流动相组成和柱温对该对映体衍生物分离的影响, 获得较好的分析条件, 分离因子大于1.2. 非手性试剂柱前衍生化法测定仲丁胺光学纯度与旋光度方法比较, 结果一致. 方法可用于仲丁胺对映体的质量控制.     

Iodide analysis by ion chromatography on a new stationary phase of polystyrene-divinylbenzene agglomerated with polymerized-epichlorohydrin-dimethylamine

A new stationary phase for iodide ion analysis has been developed. The cationic polymerepichlorohydrin-dimethylamine(PEPI-DMA) was served as modifier in synthesizing polyelectrolyte sorbents and the macroporous polystyrene-divinylbenzene(PS-DVB) resin was used as support. The positively charged polymer(PEPI-DMA) was electrostatically bonded to a negatively charged particle(PS-DVB sulfonated). The new stationary phase was characterized by scanning electron microscopy(SEM), Fourier transform infrared(FTIR), elemental analysis, chemical adsorption and desorption measurements. The chromatographic evaluation of the new stationary phase was performed using various anions with a conductivity detector. The new stationary phase was also applied to the determination of iodide directly with a DC amperometric detector using a platinum working electrode and an Ag/Ag Cl reference electrode. The chromatographic conditions were optimized and the eluent solution contained 5 mmol/L HNO3 and 15 mmol/L Na NO3 at a flow rate of 1.0 m L/min and column temperature of 30 8C. The applied voltage of the DC amperometric detector was 0.9 V. Under the optimum conditions, the linear range of the method was 0.2–50 mg/L for iodide ion with a correlation coefficient of 0.9990. The detection limit was 0.05 mg/L(calculated at S/N = 3) and the relative standard deviations(RSD, n = 6) were all less than 1% for retention time, peak area and peak height. This method was also utilized for the determination of iodide ions in samples of povidone iodine solution and kelp samples with satisfactory results.     

Optimization of the determination of inorganic and organic selenium species using high-performance liquid chromatography-electrothermal atomic absorption spectrometry

The liquid chromatographic simultaneous separation of selenite, selenate, selenocystine and selenomethionine was studied with a selenium-specific detector; electrothermal atomic absorption spectrometry. Three chromatographic modes were compared; two ion-pairing ones using either a cationic or an anionic reagent and ion-exchange. Separation parameters such as composition, pH and concentration of the mobile phase were investigated. The influence of chromatographic conditions on the sensitivity of the detector is studied. The ion-exchange method was determined to give the best results, with detection limits ranging from 8 to 17 μg l⁻¹ within a 30 min separation time. An application of this method to the analysis of seleno compounds present in a selenium-rich yeast after enzymic hydrolysis extraction is presented.     

Application of an electrochemical detector to the determination of procarbazine hydrochloride by high-performace liquid chromtography

An amperometric flow-through detector with a carbon paste working electrode was utilized as a high-performance liquid chromatographic (HPLC) detector to determine procarbazine hydrochloride, an antineoplastic agent, in both buffer solution and biological fluids. The HPLC system included an amino-cyano stationary phase and an aqueous (pH 7)-methanolic mobile phase which enabled the separation of procarbazine from its only electroactive degradation product, N-isoprophyl-a- (2-methylhydrazono)-p-toluamide. The electrochemical detector, with an approximate limit of detection of 2 ng procarbazine injected, was 20 times more sensitive to procarbazine than a typical UV detector. The low dead volume (I μl) and superior selectivity of the electrochemical detector enabled the HPLC determination of procarbazine in untreated human urine and plasma.     

Micropacked column gas chromatography with vapour of organic substance as the mobile phase

Summary Retention behaviours of aromatic hydrocarbons were examined by using the vapour of an organic substance as the mobile phase and silica gel as the stationary phase. Gas chromatographic separation of aromatic hydrocarbons was demonstrated by using a system comprising a liquid chromatographic (LC) pump, a micropacked column for LC, a column oven and a UV detector.     

Determination of Homocystine as Dabsyl Derivative by Hplc Using Precolumn Derivatization

ABSTRACT

An HPLC method has been developed for the determination of homocystine. Homocystine was converted to its chromophoric dabsyl derivative and was chromatographed by a reversed phase chromatographic column (μ-Bondapak C) with pH = 3 phosphate buffer-acetonitrile (60:40) as isocratic mobile phase. The derivative was detected by a variable wavelength detector operating at 436 ran. A linear relationship was obtained between peak areas and homocystine concentrations over the range of 0.54-2.68 μg/20 μl.     

Determination of phenobarbital in plasma by micellar liquid chromatography

A new liquid chromatographic procedure for the determination of phenobarbital in plasma samples is described. The proposed system uses a Spherisorb octadecyl-silane ODS-2 C(18) analytical column, a guard column of similar characteristics, and a 0.03 M CTAB-3% 1-propanol at pH 7 mobile phase. The UV detector was set at 250 nm. Butabarbital was used as internal standard. Sample preparation only required the addition to the plasma samples of a 0.1 M SDS solution at pH 3 and centrifugation before injection into the chromatographic system. The limit of detection was 0.83 microg/mL of phenobarbital in plasma samples. The coefficients of variation were lower than 7. 5%.     

高效阴离子交换色谱在易极化阴离子痕量分析中的应用

以45 mmol/L的 NaOH溶液作淋洗液,采用强亲水性的IonPac AS16阴离子交换分析柱和脉冲安培检测器,在15 min内分离检测了Br-,S2O2-3,I-和SCN-4种易极化阴离子,检测限(以3倍信噪比计)分别为0.5,0.2,0.05和2 μg/L (进样25 μL)。痕量离子的标准溶液平行9次进样测定的相对标准偏差为0.8%～3.7%。而在相同的色谱条件下,抑制型电导检测器对上述4种阴离子的检测限分别为1,1,2和10 μg/L,平行9次进样测定的相对标准偏差为0.9%～4.7%。通过实验比较可知,脉冲安培检测器的灵敏度是抑制型电导检测器的2～40倍。在测定上述易极化阴离子时,脉冲安培检测器具有选择性强、精密度好和灵敏度高等优点。     

Fluorescence high performance liquid chromatographic determination of 3 alpha-hydroxysteroids in urine of 21-hydroxylase deficiency

A fluorescence high performance liquid chromatographic method using an immobilized 3 alpha-hydroxysteroid dehydrogenase column as a post-column enzymatic reactor was developed for the determination of corticosteroid metabolites in the urine of subjects with congenital adrenal hyperplasia. 3 alpha-Hydroxysteroids, such as pregnanetriol, pregnanediol and pregnanetriolone, in the eluate from mu-Bondapak phenyl column (300 x 3.9 mm I.D.) using 0.05% ammonium phosphate buffer (pH 7.1)-acetonitrile-methanol (100:55:15) as the mobile phase was mixed with NAD+ solution in the enzyme column at 30 degrees C to generate NADH, which was monitored by a fluorophotometric detector. Each steroid was measured at the 2.5 micrograms/dl at the highest sensitivity of the detector. The mean recoveries and reproducibilities were 91.5-108.2% with 0.9-6.5% (CV%).     

Identification of bromination products of chloro-substituted anilines in aqueous environment by gas chromatography

To reduce the detection limits of aniline and its various chloroderivatives (all isomers of mono- and dichloroanilines, 2,4,5 -, 2,4,6-, and 3,4,5-trichloroanilines, pentachloroaniline) in aqueous media we suggested bromination reaction, followed by gas chromatographic definition bromo derivatives of chloroanilines on a selective electron capture detector. To identify the products of bromination of chloroaniline in combination with mass-spectrometric data we used chromatographic retention indices on standard nonpolar polydimethylsiloxane stationary phase that was determined for 50 compounds in this class. The technique of identifying bromoderivatives of chloroaniline in water was developed at the gas-chromatographic analysis in the selective electron capture detector. To improve the reliability of the identification of additional bromoderivatives of chloroanilines we obtained their trifluoroacetyl derivatives.