化学计量学在过程分析中应用及进展

评述了化学计量学方法在生产过程分析中各个方面，如过程优化、过程模拟、仪器及仪器校正、过程监测等方面的应用，并展望了化学计量学在过程分析中的应用前景。     

《化学计量学方法》（第二版）简介

《化学计量学方法》（第二版）在第一版的基础上补充了最新出现的化学计量学研究方法和最新的研究成果。该书包括了化学计量学的主要内容，全书共分15章，分别为误差及与数理统计基础、回归分析、相关分析和数据平滑、最优化方法、主成分分析和因子分析、偏最小二乘方法、多元校正及分辨、小波分析、遗传算法和模拟退火算法、人工神经网络法及在化学中的应用、模拟识别方法、化合物结构表征和构效关系研究、组合化学、谱图库检索和结构解析专家系统及实验设计。此外，为方便读者查阅，该书还将常用数据信息列为附表。     

化学计量学在锕系元素分析中的应用

锕系元素的化学性质相似,各元素的分离和分析都很困难,用传统的数据解析手段,难以实现各元素的同时、快速分析。化学计量学是一种高效、功能强大的数据解析方法,对于样品复杂,基体干扰严重以及多组分样品的分析具有独特优势。将化学计量学应用于锕系元素的分析中,利用数学分离代替化学分离,可直接对样品进行测定。化学计量学方法也可用来指导试样的科学采集,进行实验设计、仪器分析操作条件选择等。从吸收光谱、ICP–AES及放射性测量3个方面综述了化学计量学在锕系元素分析中的应用,阐明了化学计量学在锕系元素分析中的应用难点及发展前景。     

超高效液相色谱法结合化学计量学分析评价4种商品人参的质量

建立了快速、灵敏、准确的超高效液相色谱方法,用来分析4种商品人参(人参、红参、人参叶、人参须)中12种人参皂苷的含量,并用化学计量学方法评价了商品人参的质量。采用ACQUITY UPLC^TM BEH C₁₈色谱柱(50 mm×2.1 mm, 1.7 μm),以乙腈-水为流动相进行梯度洗脱。对所建立的测定12种人参皂苷的UPLC方法进行了线性方程、准确度、重复性、回收率等方法学考察。采用聚类分析和主成分分析的化学计量学方法对4种商品人参进行分析,评价了其质量。结果表明聚类分析和主成分分析2种化学计量学方法非常适合大样本、多成分的中药材质量分析。     

化学计量学―光谱法在工农业生产中的应用

化学计量学是近几年发展迅速的化学量测方法。常用的化学计量学方法有小波变换、多元线性回归、偏最小二乘法、主成分分析、人工神经网络、遗传算法等。化学计量学方法与光谱法相结合广泛运用于工业生产、农业生产和环境监测等各个领域,体现出化学计量学在数据处理、信号解析等方面的重要作用。化学计量学―光谱法的建立为工、农业生产中多组分混合物的快速、准确测定及满足质量监控等要求提供了一条有效的途径。     

3-己炔-2, 5-二醇在镍电极上电还原反应研究

采用化学计量学中新近发展的二维数据分辨方法,直观推导式演进特征投影(HELP)算法,对3-己炔-2,5-二醇在镍电极上的电还原反应得到的混合物进行了定性定量研究,得到了各组分的纯物质质谱及浓度变化曲线,且可以得到反应动力学的合理解释。说明借助化学计量学可大大扩展色质联用分析的应用范畴。     

3-己炔-2, 5-二醇在镍电极上电还原反应研究

采用化学计量学中新近发展的二维数据分辨方法,直观推导式演进特征投影(HELP)算法,对3-己炔-2,5-二醇在镍电极上的电还原反应得到的混合物进行了定性定量研究,得到了各组分的纯物质质谱及浓度变化曲线,且可以得到反应动力学的合理解释。说明借助化学计量学可大大扩展色质联用分析的应用范畴。     

化学计量学在电分析化学中的应用

本文对化学计量学各种方法，诸如多元校正，因子分析，信号处理，参数估计，模式识别等电分析化学中的应用作了回顾及评述，指出了化学计量学电分析化学中应用的良好前景。     

《化学计量学方法》（第二版）简介

《化学计量学方法》(第二版)在第一版的基础上补充了最新出现的化学计量学研究方法和最新的研究成果。该书包括了化学计量学的主要内容,全书共分 15章,分别为误差及与数理统计基础、回归分析、相关分析和数据平滑、最优化方法、主成分分析和因子分析、偏最小二乘方法、多元校正及分辨、小波分析、遗传算法和模拟退火算法、人工神经网络法及在化学中的应用、模拟识别方法、化合物结构表征和构效关系研究、组合化学、谱图库检索和结构解析专家系统及实验设计。此外,为方便读者查阅,该书还将常用数据信息列为附表。《化学计量学方法》(第二…     

多元分析的稳健方法

对统计学和化学计量学中发展迅速的多元稳健方法进行了系统的评述。这些稳健方法可用于化学计量学中的多元校正和模式识别。在对一些重要方法的主要思路进行了回顾的基础上，对它们的适应性和局限性本文也给出了必要的讨论。     

Flavonoids isolated from Draconis Resina

One new chalcone, 4,6-dihydroxy-2-methoxy-3-methyldihydrochalcone (4), together with four known compounds, dammaradienol (1), (-)-5-methoxyflavan-7-ol (2), 5-methoxy-6-methyl-2-phenyl-7H-chromen-7-one (3), and dracorhodin (5), were isolated from Draconis Resina. The structures of these compounds were determined by spectral methods. Among these five compounds, compounds 1, 2, and 3 exhibited cytotoxicity against KB and HepG2 cells.     

Identification of the Major Components of Resina Draconis Extract and Their Metabolites in Rat Urine by LC-ESI-MS n

The aim of our study was to employ a liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry (LC-ESI-MS ⁿ ) method for the identification of the major components of Resina Draconis extract (RDE) and their metabolites in rat urine. Based on the above, 18 compounds were tentatively identified from the RDE. Among them, 4 compounds were unambiguously characterized by the comparison of the retention time and mass spectra with those of reference compounds and 14 compounds were tentatively identified by comparing the mass spectra with those of literature. In vivo, 21 compounds, including 13 parent compounds and 8 metabolites, were detected in rat urine after oral administration of RDE. The results may be helpful for future research on traditional Chinese medicine.     

Differentiation of Resina Draconis from Sanguis Draconis by CE

A simple, accurate method based on capillary electrophoresis with electrochemical detection (CE–ED) has been developed to determine loureirin A, loureirin B and dracorhodin for differentiation of Resina Draconis from Sanguis Draconis. The effects of some important factors such as acidity and concentration of running buffer, separation voltage, injection time, and applied potential on the CE–ED working electrode were investigated. Under the optimum conditions, the three analytes could be well separated within 30 min in a 75 cm capillary at a separation voltage of 14 kV in a 80 mmol L^?1 borate buffer (pH 9.24). The working electrode was a 300-μm-diameter carbon disc electrode positioned opposite the outlet of the capillary in a wall-jet configuration and was set at a potential of 0.90 V (vs. SCE). Excellent linearity was established over two orders of magnitude with detection limits (S/N = 3) ranging from 3 × 10^?7 g mL^?1 to 1 × 10^?6 g mL^?1 for all three analytes. The relative standard deviations of peak current and migration times of loureirin A, loureirin B and dracorhodin were 2.1, 1.7, 4.4 and 2.9, 2.8, 3.3% (n = 5), respectively. The recoveries of three constituents ranged from 98.8 to 101.8%. The methodology has been successfully applied to analyze and differentiate the actual samples with satisfactory assay results.     

Analysis of the essential oils of Coriandrum sativum Using GC-MS coupled with chemometric resolution methods

The essential oils extracted from Coriandrum sativum L. were analyzed by GC-MS coupled with chemometric resolution methods. Through the chemometric resolution methods, peak clusters were uniquely resolved into the pure chromatographic profiles and mass spectra of each component. Qualitative analysis was performed by comparing the pure mass spectra with those in the NIST 05 mass spectral library. Quantitative analysis was performed using the total volume integration method. A total of 118 constituents were detected, of which 104 were identified, accounting for 97.27% of the total content. The results indicate that GC-MS combined with chemometric resolution methods can greatly enhance the capability of separation and the reliability of qualitative and quantitative results. The combined method is an economical and accurate approach for the rapid analysis of the complex essential oil samples in Coriandrum sativum L.     

Investigation of the acid-base properties of mononitro-calix[4]arene with chemometric methods

The acid-base properties of mononitro-calix[4]arene was studied with chemometric methods by measurement of its UV absorbance under different pH. The chemometric method-iterative target transformation factor (ITTFA) was employed to resolve the acid-base fraction curves. Combining with other chemometric methods-principal component analysis (PCA) and evolving factor analysis (EFA), the proton dissociation behavior of the derivative was investigated in detail. The pK(a) values of the derivative were determined and the fraction curves and pure absorbing spectra of each absorbing component were obtained.     

Chemometrics in near-infrared spectroscopy

Spectroscopy methods of chemical analysis are excellent for the application of chemometric methods, because the measurements at many different wavelengths provide inherently multivariate data. The chemist generally requires three categories of information from specimens under investigation: quantitative data, qualitative data, and fundamental information on the properties of the material. Spectroscopy has long been used for all three purposes; the recent application of chemometric algorithms has assisted greatly in these endeavors. Although there is some overlap, three chemometric methods correspond to the three types of information: multiple regression, discriminant analysis, and principal components analysis. The basis of these chemometric methods and some of their strengths and limitations in application to near-infrared spectroscopy are discussed.     

Chemometric approaches in environmental problems concerning PCDD and PCDF. Data interpretation and source correlation. Mechanisms of formation and destruction in MSW combustion process

Summary The role of multivariate analysis methods in evaluating, rationalizing, and working out complex environmental problems is discussed. The discussion is organized in two sections; a literature analysis of the application of chemometric methods to PCDD/PCDF data interpretation and source correlation and a review of the role of chemometric methods in analysing the results obtained by the Authors studying PCDD/PCDF formation and destruction mechanisms in MSW combustion processes.     

Determination of volatile components in peptic powder by gas chromatography-mass spectrometry and chemometric resolution

Gas chromatography-mass spectrometry (GC-MS) coupled with chemometric resolution upon two-dimensional data was proposed as a method for the analysis of volatile components in a traditional Chinese medicinal preparation peptic powder which contains Rhizoma Atractylodis, Pericarpium Citri Reticulatae, Cortex Magnoliae Officinalis and Radix Glycyrrhizae. Ninety-three components were separated and 65 of them were qualitatively and quantitatively analyzed which represented about 90.28% of the total content. With the help of chemometric resolution, the data were resolved into a pure chromatogram and a mass spectrum of each chemical component. The accuracy of qualitative and quantitative results was greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra. The example showed that chemometric resolution could greatly enhance separation ability. This makes it possible to analyze complicated practical systems like traditional Chinese medicinal preparations with the help of coupled instruments and chemometric resolution methods.     

Simultaneous Determination of Guaifenesin and Theophylline by Chemometrics Methods

In this study, simultaneous spectrophotometry determination of guaifenesin and theophylline in pharmaceuticals by chemometric approaches has been reported. Spectra of mixtures of these drugs were recorded and corresponding first derivatives were calculated. Partial least squares regression (PLS) alone and ant colony optimization (ACO) coupled with PLS were used in analysis of the data. Ant colony system (ACS) as an efficient ACO algorithm was used. In addition, ACS was combined to genetic algorithm (GA) to produce better results. The analytical performances of these chemometric methods were characterized by relative prediction errors. These methods were successfully applied to pharmaceutical formulation.     

Simultaneous spectrophotometric determination of paracetamol, ibuprofen and caffeine in pharmaceuticals by chemometric methods

In this study, the simultaneous determination of paracetamol, ibuprofen and caffeine in pharmaceuticals by chemometric approaches using UV spectrophotometry has been reported as a simple alternative to using separate models for each component. Spectra of paracetamol, ibuprofen and caffeine were recorded at several concentrations within their linear ranges and were used to compute the calibration mixture between wavelengths 200 and 400 nm at an interval of 1 nm in methanol:0.1 HCl (3:1). Partial least squares regression (PLS), genetic algorithm coupled with PLS (GA-PLS), and principal component-artificial neural network (PC-ANN) were used for chemometric analysis of data and the parameters of the chemometric procedures were optimized. The analytical performances of these chemometric methods were characterized by relative prediction errors and recoveries (%) and were compared with each other. The GA-PLS shows superiority over other applied multivariate methods due to the wavelength selection in PLS calibration using a genetic algorithm without loss of prediction capacity. Although the components show an important degree of spectral overlap, they have been determined simultaneously and rapidly requiring no separation step. These three methods were successfully applied to pharmaceutical formulation, capsule, with no interference from excipients as indicated by the recovery study results. The proposed methods are simple and rapid and can be easily used in the quality control of drugs as alternative analysis tools.