内燃机油高效液相指纹图谱的建立

建立了内燃机油指纹图谱的高效液相色谱(HPLC)分析方法。采用反相C18柱,以乙腈-水为流动相梯度洗脱,检测波长280 nm,柱温30℃,进样体积10μL进行试验。考察结果表明,指纹图谱中各共有色谱峰的相对保留时间α和相对峰面积Sr的相对标准偏差(RSD)均小于2.4%,满足小于3%的指纹图谱研究技术要求。通过共有特征峰分析以及色谱峰重叠率、相似度的计算,可进一步鉴别和评价内燃机油的质量。该法与传统的内燃机油品质评价方法相比,节约了试验成本和时间,为内燃机油的快速鉴别和质量控制开拓了新领域。     

穿心莲药材高效液相色谱指纹图谱研究及其应用

应用反相高效液相色谱(RP-HPLC)法建立穿心莲药材指纹图谱。首先以穿心莲对照药材为对象建立其乙醇提取物特征色谱图,再用5种不同来源穿心莲药材的乙醇提取物验证色谱图的指纹特性。在穿心莲药材乙醇提取物特征色谱图中有共有峰10个,各共有峰的相对保留时间与相对峰面积的相对标准偏差(RSD)均小于4%。对照药材中共有峰峰面积占总峰面积的98.5%以上。该指纹图谱用于清火栀麦胶囊中穿心莲的鉴别专属性良好。     

平行五波长高效液相色谱指纹图谱全息整合法定量鉴定杞菊地黄丸的整体质量

建立了杞菊地黄丸(Qijudihuang Pill, QJDHP)平行五波长(PFW)高效液相色谱(HPLC)指纹图谱,并依据系统指纹定量法结合全息整合法定量鉴定了杞菊地黄丸的整体质量。采用反相HPLC法,以丹皮酚(POL)为参照物峰,分别于203、228、265、280和326 nm下检测,分别确定了51、49、52、49和47个共有指纹峰,建立了QJDHP的PFW-HPLC指纹图谱。分别以权重法、均值法和投影参数法整合5个波长下各样品的定性定量全信息,结果基于5个波长综合信息用系统指纹定量法鉴定11批QJDHP样品,其中有8批质量为好,1批为较好,质量一般为2批。评价时以均值法最为简捷和准确。本实验结果表明,平行多波长指纹图谱整合法是基于从全信息角度整体定性和定量鉴定中药质量的有效可信方法,是对HPLC-二极管阵列检测（DAD）三维指纹图谱的简化定量处理,其整体综合定量鉴定结果具有可靠性。     

大豆异黄酮指纹图谱中保留时间漂移的校正研究

选取5个极性不同的化合物作为标准样品,在不同仪器及不同色谱柱上采用已建立的大豆异黄酮高效液相色谱(HPLC)指纹图谱条件进行测定,以它们在不同色谱仪(或柱)上的保留时间进行线性回归,并用得到的线性方程对相同条件下测得的大豆异黄酮指纹谱中峰面积为总峰面积1.5%以上的色谱峰的保留时间进行校正,通过校正使保留时间的最大绝对误差由5.868 min减小为0.854 min。采用该方法可以校正相同色谱条件但不同实验室间指纹图谱保留时间的漂移,提高HPLC指纹图谱的重现性。     

基于水溶性浸出物及HPLC指纹图谱评价不同贮存年限半夏的品质

研究不同贮存年限半夏药材的浸出物,建立浸出物的HPLC特征指纹图谱,为半夏药材品质评控提供参考。浸出物测定方法采用药典法;HPLC指纹图谱的色谱条件:采用C_(18)色谱柱(150 mm×4.6 mm,5μm),以水–甲醇为流动相,梯度洗脱,流量为0.8 m L/min,检测波长为260 nm,柱温为25℃,进样体积为50μL。采用相似度评价及聚类分析技术揭示14批样品的相似性及差异性。14批半夏浸出物有12批合格,2批不合格。建立14批半夏浸出物样品的高效液相指纹图谱,确定了3个共有峰,共有峰保留时间的相对标准偏差小于2%,峰面积的相对标准偏差差异较大。1~#~7~#半夏样品有12个共有峰,共有峰保留时间的相对标准偏差小于1.5%,峰面积的相对标准偏差差异较大。各批次药材化学成分组成及含量均存在一定差异。以半夏浸出物数据与其高效液相色谱指纹图谱数据为基础,将指纹图谱相似度评价与聚类分析结合起来,用浸出物含量及评价软件测评结果对半夏品质进行综合评估,可以更精确地对半夏药材进行质量控制。     

原料奶在HPLC-MS负离子模式下的指纹图谱研究

采用高效液相色谱质谱联用技术,在负离子扫描模式下建立了原料奶的乙腈提取成分的指纹图谱。采用乙腈和0.1％的乙酸为流动相进行二元梯度洗脱,柱温30℃,分析时间为85 min。确定了11个共有峰,以7号峰为参照物,通过相对峰面积和相对保留时间进行了方法学考察。结果表明,本方法具有良好的重现性,各指纹峰相对保留时间的RSD<0.79％,相对峰面积的RSD<2.84％。在原料奶指纹图谱基础上,选取有代表性有害物如防腐剂苯甲酸等进行了标准添加,建立了添加图谱,对沈阳地区超市的50个纯牛奶样品进行了筛查,取得初步应用结果。     

原料奶的高效液相色谱指纹图谱的建立

采用高效液相色谱-质谱联用(HPLC-MS)技术,在负离子扫描模式下建立了原料奶的乙腈提取成分的指纹图谱。采用乙腈和0.1%的乙酸水溶液为流动相进行二元梯度洗脱,柱温30℃,分析时间为85min。确定了11个共有峰,以其中的7号峰为参照物,通过相对峰面积和相对保留时间进行了方法学考察。结果表明,本方法具有良好的重现性,各指纹峰相对保留时间的相对标准偏差(RSD)小于0.79%,相对峰面积的RSD小于2.84%。在原料奶指纹图谱基础上,选取有代表性的危害物如防腐剂苯甲酸等进行了添加,建立了危害物添加图谱,对沈阳地区超市的50个纯牛奶样品进行了筛查,取得初步的应用结果。     

色谱指纹图谱在苹果酒质量评价中的应用

采用反相高效液相色谱-电化学检测法研究了14种苹果酒样品的指纹图谱。以标准品绿原酸进行定位,通过对图谱分析和相对保留时间计算,确定了8个共有峰。根据共有峰的峰面积用相关系数法和向量夹角余弦法计算相似度,两种方法的计算结果一致。实验结果表明同一厂家生产的苹果酒相似度较好。该法为苹果酒的产品分析提供了有效的微观信息,为苹果酒的质量控制、新产品的研发以及苹果酒行业标准的制定提供一种可行思路。     

高效液相色谱指纹图谱在中药芦根上的应用

利用现代分离分析技术如高效液相色谱(HPLC)与气相色谱(GC),能够获得中草药的色谱指纹图谱。本实验报道了高效液相指纹图谱应用于快速检测中草药提取物以及应用于研究、开发与生产中的质量控制体系中,利用HPLC建立芦根的色谱指纹图谱。实验条件为反相C18柱,流速为1．0mL／min,紫外检测器(λ=230nm)。通过分析比较色谱指纹图谱中的相对保留值α以及相对面积St对不同产地的芦根进行对比研究。这种基于HPLC的分析策略为中草药的精确鉴定和质量控制提供了有效的信息,并为HPLC在复杂组分样品中的应用开拓了新的领域。     

加压毛细管电色谱法用于银杏叶的指纹图谱研究

采用反相加压毛细管电色谱(pCEC)法,建立了银杏叶的pCEC指纹图谱.以芦丁为内标,确定银杏叶的pCEC指纹峰为29个.测定了10个产地银杏叶的pCEC指纹图谱,其中9个产地的指纹图谱相似度系数为0.900～0.991.本方法具有较好的精密度,各指纹峰相对迁移时间的相对标准偏差(RSD)< 2.6 % ,相对峰面积的RSD≤3.5%.此方法样品和试剂用量少少,对复杂样品分离能力强,可用于银杏叶药材的质量控制.     

Fingerprint Studies of Radix Scutellariae by Capillary Electrophoresis and High Performance Liquid Chromatography

Two methods based on capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) are described to establish fingerprints of Radix Scutellariae simultaneously. In order to choose an appropriate extraction method, Radix Scutellariae samples extracted by different methods were determined by HPLC. The contents of baicalin, the quality marker of Radix Scutellariae, as well as the number of peaks in the chromatograms were determined to evaluate the extraction methods. 10 batches of Radix Scutellariae collected from different regions in China were applied to establish the fingerprints. Eleven common peaks were isolated within 12 min by CE. The fingerprints obtained with HPLC consisted of 14 common peaks within 40 min. The two proposed methods demonstrated good stability and reproducibility with RSD less than 4% for relative migration time in CE and retention time in HPLC. Finally, the data from the 10 batches of Radix Scutellariae by CE and HPLC were all processed with two kinds of mathematical methods including correlation coefficient and the included angle cosine. The fingerprints of Radix Scutellariae established with CE and HPLC are suitable to identify and differentiate samples by geographical origin and can used for quality control.     

Chromatographic methods for determination of S-substituted cysteine derivatives—A comparative study

A novel HPLC method for determination of a wide variety of S-substituted cysteine derivatives in Allium species has been developed and validated. This method allows simultaneous separation and quantification of S-alk(en)ylcysteine S-oxides, γ-glutamyl-S-alk(en)ylcysteines and γ-glutamyl-S-alk(en)ylcysteine S-oxides in a single run. The procedure is based on extraction of these amino acids and dipeptides by methanol, their derivatization by dansyl chloride and subsequent separation by reversed phase HPLC. The main advantages of the new method are simplicity, excellent stability of derivatives, high sensitivity, specificity and the ability to simultaneously analyze the whole range of S-substituted cysteine derivatives. This method was critically compared with other chromatographic procedures used for quantification of S-substituted cysteine derivatives, namely with two other HPLC methods (derivatization by o-phthaldialdehyde/tert-butylthiol and fluorenylmethyl chloroformate), and with determination by gas chromatography or capillary electrophoresis. Major advantages and drawbacks of these analytical procedures are discussed. Employing these various chromatographic methods, the content and relative proportions of individual S-substituted cysteine derivatives were determined in four most frequently consumed alliaceous vegetables (garlic, onion, shallot, and leek).     

Ganoderma species discrimination by dual-mode chromatographic fingerprinting: A study on stationary phase effects in hydrophilic interaction chromatography and reduction of sample misclassification rate by additional use of reversed-phase chromatography

Acetonitrile–water extracts of several Ganoderma species – a mushroom being used in Traditional Chinese Medicine – were analysed by liquid chromatography–UV detection in hydrophilic interaction chromatography (HILIC) and reversed-phase (RP) elution modes. A set of six polar stationary phases was used for HILIC runs. These columns had remarkably different separation properties under binary gradient conditions as evinced by hierarchical cluster analysis on retention patterns of seven test compounds. Complementary measurements of RP chromatograms were carried out on a C₁₈ packing. Injection precision (n = 5) and intra-day precision (n = 5) were each <2.0% RSD (HILIC) and <0.7% RSD (RP) for relative retention times of main characteristic peaks of a sample extract while for relative peak areas RSD values were max. 6.8%. Repetitive analysis (n = 7) of a processed sample stored in the autosampler tray for 48 h was used to confirm within-sequence sample stability. Eleven Ganoderma lucidum samples served as training set for the construction of column-specific simulated mean chromatograms. Validation with twelve samples comprising G. lucidum, Ganoderma sinense, Ganoderma atrum, and Ganoderma tsugae by correlation coefficient based similarity evaluation of peak patterns showed that a discrimination of G. lucidum from other Ganoderma species by means of chromatographic fingerprints is conceptually possible on all columns, except of a bare silica packing. The importance of the combined use of RP and HILIC fingerprints to improve the rate of correct sample classification was demonstrated by the fact that each one G. sinense specimen was wrongly assigned being G. lucidum by all HILIC fingerprints but not the RP fingerprint and vice versa. The present data revealed that (i) the analysis of complex biological materials by quasi orthogonal chromatographic modes such as HILIC and RP may deliver more discriminative information than single-mode approaches which strengthens the reliability of fingerprint-based sample classification and (ii) different retention and selectivity characteristics of polar bonded silica packings in the HILIC elution mode may only have a minor impact on chemometric sample discrimination capabilities in such kind of pattern-oriented metabolomics separation problems.     

Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (π^*) and hydrogen-bond basicity (β), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents.     

Application of perfluorinated acids as ion-pairing reagents for reversed-phase chromatography and retention-hydrophobicity relationships studies of selected β-blockers

The addition of the homologous series of perfluorinated acids-trifluoroacetic acid (TFAA), pentafluoropropionic acid (PFPA), heptafluorobutyric acid (HFBA) to mobile phases for reversed-phase high-performance liquid chromatography (RP-HPLC) of β-blockers was tested. Acidic modifiers were responsible for acidification of mobile phase (pH 3) ensuring the protonation of the β-blockers and further ion pairs creation. The effect of the type and concentration of mobile phase additives on retention parameters, the efficiency of the peaks, their symmetry and separation selectivity of the β-blockers mixture were all studied. It appeared that at increasing acid concentration, the retention factor, for all compounds investigated, increased to varying degrees. It should be stressed that the presence of acids more significantly affected the retention of the most hydrophobic β-blockers. Differences in hydrophobicity of drugs can be maximized through variation of the hydrophobicity of additives. Thus, the relative increase in the retention depends on either concentration and hydrophobicity of the anionic mobile phase additive or hydrophobicity of analytes. According to QSRR (quantitative structure retention relationship) methodology, chromatographic lipophilicity parameters: isocratic log k and log k_w values (extrapolated retention to pure water) were correlated with the molecular (log P_o/w) and apparent (log P_app) octanol–water partition coefficients obtained experimentally by countercurrent chromatography (CCC) or predicted by Pallas software. The obtained, satisfactory retention-hydrophobicity correlations indicate that, in the case of the basic drugs examined in RP-HPLC systems modified with perfluorinated acids, the retention is mainly governed by their hydrophobicity.     

Quantitative TLC Analysis of Steroid Drug Intermediates Formed During Bioconversion of Soysterols

A simple, rapid, and accurate method based on thin-layer chromatography (TLC) combined with image-analysis software has been developed for analysis of steroid drug intermediates formed during bioconversion of soysterols. The results obtained have been compared with those from LC. The method has been used to monitor the accumulation of widely used steroid drug intermediates androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD), formed during the bioconversion of soysterols by Mycobacterium sp. NRRL B-3805 and Mycobacterium sp. NRRL B-3683. The percentage error between TLC and LC ranged between ?0.79 to +4.50 for AD and ?0.61 to +2.48 for ADD. Maximum conversion of soysterols to AD and ADD by Mycobacterium sp. NRRL B-3805 was 49.83 and 9.36 mol%, respectively, after incubation for 144 h, whereas conversion of soysterols by Mycobacterium sp. NRRL B-3683 after incubation 288 h was 41.90 mol% for AD and 37.79 mol% for ADD.     

Fingerprint Analysis of Flos Carthami by Pressurized CEC and LC

A fingerprint analysis of Flos Carthami was performed using a standardized capillary electrochromatography (CEC) procedure. This procedure was first used to establish the electrochromatographic profile of genuine Flos Carthami from Tacheng, Xinjiang, China. This Flos Carthami fingerprint was then used to identify and assess the consistency of raw herbs from different sources in China. The study of a limited number of samples from ten different sources demonstrated a reasonable consistency among their CEC fingerprints relative to that of the genuine sample. Using this technique, we can readily distinguish the fingerprint of Flos Carthami from that of Stigma Croci, a possible substitute in traditional Chinese medicine, and Flos Hemerocallis, a commercial adulterant. A method based on high performance liquid chromatography (HPLC) is described to establish fingerprints of Flos Carthami simultaneously. The fingerprints obtained with HPLC consist of 21 common peaks within 65 min while 43 common peaks obtained with CEC. CEC showed better performance on fingerprinting of hydroxysaffloryellow A and its neighboring peaks, which contained more chemical information than that of HPLC. It was proven that CEC could be a feasible and effective method for development of fingerprint of TCM based on the comparison with HPLC.     

A biomimetic approach to the synthesis of a mycolic acid motif

A new method for the stereoselective synthesis of the (R,R)-β-hydroxy-α-alkyl fatty acid fragment of mycolic acids, via an asymmetric anti-aldol reaction is reported. The ‘mycolic acid motif’ fragment was prepared in three steps and >98% ee.     

Potential antioxidant compounds in Mallotus species fingerprints. Part II: Fingerprint alignment,data analysis and peak identification

Some Mallotus species are commonly used as traditional medicine (TM) ingredients in Vietnam and China, but only a few are studied for their activities. In Part I, high-performance liquid chromatography (HPLC) fingerprints of 39 Mallotus samples (17 species) were developed and, because of the complexity of and the large differences between the samples, it was chosen to analyse the unaligned fingerprints. The peaks, potentially responsible for the antioxidant activity in given Mallotus species, were indicated by the regression coefficients from an orthogonal projections to latent structures (O-PLS) model. In the present study, an in depth discussion on the need for alignment of the Mallotus fingerprints for the indication of the potentially active compounds is made, as well as an experimental analysis and identification of the previously indicated peaks by HPLC–mass spectrometry (HPLC–MS). Additionally, to thoroughly study and discuss the alignment problem, the modelling and prediction of the antioxidant activity of green tea samples based on HPLC fingerprints were also considered.