Chromatogram surgery

A computer program is developed on a Hewlett-Packard 3354 B Laboratory Automation System to eliminate background in gas and liquid chromatograms. Moreover undesired peaks, such as solvent peaks and spikes, can be excluded by selecting appropriate method parameters or by application of the integrator-timed events directly affecting peak integration. Injudicious application of these codes deforms the chromatograms. Peaks can be labelled with retention times, areas or amounts.     

茶叶指纹谱的毛细管胶束电动色谱法研究

 用胶束电动色谱法建立了茶叶的色谱指纹谱并用于分析10种中国名茶。这种色谱指纹谱是由相对保留值(α)和相应的相对峰面积(Sr)组成的。该方法将色谱图转换成数据表,实现了图谱的数据化;并且以相对保留值表示各色谱峰的峰位,大大减少了各种操作条件对色谱相对保留值的影响,降低了色谱峰峰位变化的波动性,提高了样品间的可比性。这种色谱指纹谱在没有标准品的情况下也可得出可靠的、有意义的结果。优化后的色谱条件是:电泳电解质为硼砂0.02 mol/L 、十二烷基硫酸钠(SDS)浓度为0.025 mol/L 的溶液(pH     

离子色谱法测定氯化石蜡中的总氯量

采用氧瓶燃烧法处理氯化石蜡样品,用离子色谱测定吸收液中Cl^-的方法来确定氯化石蜡的总氯量。在Metrosep A SUPP5型阴离子分离柱上,以3．2mmol／LNa2CO3和1．0mmol／LNaHCO3混合溶液作为淋洗液,抑制型电导检测,检出限为0．87μg／L,线性范围0．1—4mg／L,相对标准偏差与回收率分别为1．71％～2．14％、94．4％-103．1％。该方法简便、快速,结果与国家标准法比较无显著性差异。     

栀子药材的指纹图谱整体性分析

建立了药材栀子水提部分的高效液相色谱指纹图谱,脂溶性成分和挥发油的气相色谱．质谱联用指纹图谱,并分别计算了此3部分指纹图谱的相似系数和总体相似系数,同产地结果RSD≤5％。通过比较不同产地栀子相似系数的关系,以及对9个主要药效成分定量结果的分析,对不同产地栀子的指纹图谱做了整体性评价,结果表明,只有全面测定成分及整体性评价后,药材的质量才能得到有效评价。     

葛根药材指纹图谱分析方法研究

以安徽产葛根药材为分析对象,选择Agilent ZORBAX SB-C18柱(4.6 mm×250 mm,5μm),甲醇-水梯度洗脱,流量为0.9 mL.min-1,检测波长为250 nm,柱温25℃,建立了葛根药材HPLC指纹图谱。结果表明,10批供试品的保留时间在60 min之内,共有18个典型的共有色谱峰。采用HPLC法获得的葛根药材指纹图谱稳定、可靠、重复性好,能较全面地反映葛根药材的内在质量,可用于葛根药材的质量控制。     

Fingerprint Chromatogram Analysis of Radix Glehniae by LC Coupled with Hierarchical Clustering Analysis

For the first time a validated liquid chromatography method coupled with hierarchical clustering analysis has been developed for the study of fingerprint chromatograms of extracts from the Radix Glehniae of Glehnia littorali. Liquid chromatography with gradient elution was performed on extracts from 23 plant samples collected from different geographical locations. Ten of twenty-three plant samples were selected using hierarchical clustering analysis and employed to establish the fingerprint. The fingerprint was established and ten chromatographic peaks were selected as characteristic peaks and panaxynol was used as reference standard compounds. The fingerprint chromatograms had a good stability, precision, and reproducibility. This method is a very reliable and useful method for assessment of the quality of Radix Glehniae.     

生姜精油的超高效合相色谱特征图谱研究

应用超高效合相色谱(UPC~2)技术研究了生姜精油的特征图谱。生姜精油经正庚烷稀释,以超临界CO_2为流动相,乙腈为助溶剂,采用超高效合相色谱梯度洗脱分离,流速为0.8 mL/min,二极管阵列(PDA)检测器测定,建立了特征峰PDA光谱谱图库及安徽产生姜精油的标准对照特征图谱。通过特征峰PDA光谱图检索识别及色谱图相似度评价,10份安徽产生姜精油的样品谱图与标准对照特征图谱的相似度均大于0.9。各共有指纹峰相对保留时间和相对峰面积的相对标准偏差(RSD)均小于3.0%,方法精密度、重现性、稳定性良好,符合特征图谱评价要求。通过超高效合相色谱特征图谱采集,结合聚类分析、主成分分析,对20批不同来源的生姜精油样品成功进行了区分。该研究为生姜精油的质量控制及产地溯源提供了一种简便、快速的新方法。     

Bimodal Gel Permeation Chromatogram of Acrylonitrile-Styrene Copolymers

Abstract

Gel permeation chromatograms were recorded for an acrylonitrile-styrene copolymer in both dimethylforamide (DMF) and DMF-LiBr-H₂O as solvents. In the DMF solvent, a bimodal chromatogram was observed, while in the DMF-LiBr-H₂O solvent, monomodal behavior was observed for the same sample. In order to investigate the cause for such behavior, the molecular weight averages of the copolymer were determined in these solvents. Further, the chromatogram in the former solvent was corrected for observed nonlinearity of the calibration curve. We concluded that apparent differences in the chromatograms are due, at best in part, to the nonlinearity. General conditions for the appearance of bimodal chromatograms were examined based on this idea, using simulation techniques.     

Comparisons of Five Algorithms for Chromatogram Alignment

In this study, five frequently used warping algorithms [correlation optimized warping (COW), recursive alignment by fast Fourier transform (RAFFT), dynamic time warping, variable penalty dynamic warping, and parametric time warping (PTW)] are compared for their ability to align chromatograms with retention time shifts. Five datasets consisting of chromatograms of herbal medicines analyzed by high-performance liquid chromatography (HPLC) (Kudzuvine Root, White Paeony Root, Rehmannia Root, Ligusticum wallichii, Scutellaria baicalensis) are chosen to test these five alignment algorithms. The comparison shows all those five methods have misalignments with different degrees, but the correlations of the aligned data sets are all improved, especially for the data sets that are aligned by segment-wise: COW and RAFFT. After the comprehensive comparison, RAFFT wins the highest score, and then COW follows, whereas PTW is not preferable to align HPLC.     

全二维气相色谱谱图基线校正方法的研究

拟根据全二维气相色谱谱图的特点，以第一周期的信号为初值，通过计算各周期(第二维)谱图的基线水平及噪声，去除特异值后，利用三次样条分析对基线进行重构，达到对全谱图的基线校准。以石脑油样品的全二维气相色谱分析谱图为例进行评价，校准后基平面的标准偏差为0．114，系统漂移得到良好的扣除，同一诺图数据用商品化的Zoex软件处理，基平面的标准倔差为0.614，表明本文的方法具明显优越性，为全二维气相色谱峰的准确定量确立了良好的基础。     

伴大豆球蛋白亚基色谱分离和制备及结构表征

研究了色谱方法对伴大豆球蛋白组成3个亚基的分离纯化工艺条件,并利用圆二色光谱对纯化得到的3个亚基的二级结构和三级结构进行了表征.结果显示:利用离子交换色谱(DEAE-sepharose fast flow, DEAE为二乙氨乙基)和金属螯合层析(Immobilized metal affinity column, IMAC)相结合的方法,能将3个亚基组分完全分开,得到了能制备相对大量的3个亚基α′, α和β的稳定工艺,纯度为95%,回收率达75%.远紫外CD结果显示,在3个亚基的二级结构中, α螺旋较少,但都具有较高含量的β折叠和无规卷曲; 近紫外CD结果显示, 3个亚基在制备过程中因为尿素的变性作用,都已经散失了三级结构.     

遗传算法在色谱谱图解析中的应用

将遗传算法引入色谱峰解析程序 ,结合色谱峰EMG模型及峰形经验公式 ,实现了恒温色谱谱图的全自动解析。对模拟谱图和实验谱图进行了解析 ,取得了满意的结果。本文对遗传算法的运算控制及运算效率进行了研究和讨论     

A Statistical Evaluation of Methods of Chromatogram Interpretation-GPC

Abstract

Herein is reported a statistical evaluation of two common methods of determining the molecular weight calibration curve using broad molecular weight distribution standards. A Monte-Carlo simulation technique was employed to investigate and compare error propagation in these methods. It has been common practice to evaluate methods of chromatogram interpretation on an entirely theoretical basis without consideration of error propagation in the calculation procedures employed in the various methods. It is possible for a method which has a sounder theoretical basis to give less reliable results because of excessive error propagation. A statistical evaluation of error propagation also identifies the steps in calculation procedures where serious error propagation occurs leading perhaps to alternate and improved calculation paths.

The analysis of several sources of error is presented in detail including propagation errors due to errors in the molecular weight averages of the broad molecular weight distribution standards and chromatogram replication error.     

基于小波和轮廓提取的色谱基线算法研究

把基于小波和轮廓提取的基线算法引入了色谱基线提取领域;基于轮廓提取的算法为:通过构造一个滑动窗,沿着色谱数据滑动求窗内的最小值。把这些最小值插值平滑就获得了色谱基线。基于小波和轮廓提取的算法为:先用小波初步提取基线,然后把色谱数据减去小波提取的基线后再用轮廓提取算法获得基线,把小波提取的基线和轮廓提取的基线相加即为原数据的基线。对这两个算法进行了比较实验研究,结果表明:基于小波和轮廓提取的算法比轮廓提取的算法效果好,能更准确地提取色谱基线。     

用毛细管色谱分离非对映体化合物的研究

不对称合成反应的迅速发展使各种对映异构体和非对映异构体的分离及纯度测定显得越来越重要。由于这些化合物只是个别原子空间排列不同,分子式和原子连接方式均相同,所以分离较困难。虽然高分辨核磁共振仪可以分析非对映异构体,但它有要求1mg以上纯品才能测定的缺点。而用毛细管色谱测定分子量较低的非对映异构体时,只需要微量的粗品就能快速、直观地看出异构体的相对含量。因此我们在用毛细管色谱分离几何异构体的基础     

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。     

指纹图谱法在参麦注射液质控中的应用

 中医药理论和实践要求综合评价中药的质量 ,指纹图谱法是对中药制剂进行综合宏观分析的可行手段之一 ,因此采用反相高效液相建立了参麦注射液的特征指纹图谱。条件 :Hypersil C18(4 6mmi d × 2 5 0mm ,5 μm)反相柱 ,流动相由水 (A)和乙腈 (B)组成 ,B的体积分数在 5 0min内由 5 %线性增长到 95 % ,流速为1 0mL/min ;紫外检测 ,波长为 2 0 2nm。 2 3个特征指纹峰与内标 (联苯 )的峰面积比作为指标 ,结合主成分分析 投影判别法比较了同一厂家不同批次产品和不同厂家同类产品的化学指纹差异。     

Mathematical simulation of the evaporation in operation area of a bubble evaporator

Simulation of evaporation in operation area of an evaporator is considered. We obtained a formalized model of this process and optimum conditions of an engineering system on the basis on the analysis.     

Photooxidation and reproduction of pentacene derivatives substituted by aromatic groups

Pentacene derivatives substituted by aromatic groups at the 6,13-positions were prepared and investigated for their electronic properties and the photoaddition reaction with oxygen. The pentacene derivatives substituted by 2-thienyl and phenyl groups reacted with oxygen in solution under light and afforded their endoperoxides. These first-order kinetic constants were evaluated to be 1.5×10⁻³ s⁻¹ and 2.7×10⁻³ s⁻¹. The pentacene derivative with pentafluorophenyl groups was relatively stable in solution. The thermolysis and photolysis of the endoperoxide with 2-thienyl groups in solution afforded the pentacene derivative with yields of 30 and 44%, respectively. In addition, UV irradiation (254 nm) of the thin film of the endoperoxide was studied, which indicated the reproduction of the pentacene derivative.